WorldWideScience

Sample records for subject image sequences

  1. 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.)

  2. 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 ...

  3. Region segmentation along image sequence

    Energy Technology Data Exchange (ETDEWEB)

    Monchal, L.; Aubry, P.

    1995-12-31

    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.

  4. Coronary magnetic resonance vein imaging: imaging contrast, sequence, and timing.

    Science.gov (United States)

    Nezafat, Reza; Han, Yuchi; Peters, Dana C; Herzka, Daniel A; Wylie, John V; Goddu, Beth; Kissinger, Kraig K; Yeon, Susan B; Zimetbaum, Peter J; Manning, Warren J

    2007-12-01

    Recently, there has been increased interest in imaging the coronary vein anatomy to guide interventional cardiovascular procedures such as cardiac resynchronization therapy (CRT), a device therapy for congestive heart failure (CHF). With CRT the lateral wall of the left ventricle is electrically paced using a transvenous coronary sinus lead or surgically placed epicardial lead. Proper transvenous lead placement is facilitated by the knowledge of the coronary vein anatomy. Cardiovascular MR (CMR) has the potential to image the coronary veins. In this study we propose and test CMR techniques and protocols for imaging the coronary venous anatomy. Three aspects of design of imaging sequence were studied: magnetization preparation schemes (T(2) preparation and magnetization transfer), imaging sequences (gradient-echo (GRE) and steady-state free precession (SSFP)), and imaging time during the cardiac cycle. Numerical and in vivo studies both in healthy and CHF subjects were performed to optimize and demonstrate the utility of CMR for coronary vein imaging. Magnetization transfer was superior to T(2) preparation for contrast enhancement. Both GRE and SSFP were viable imaging sequences, although GRE provided more robust results with better contrast. Imaging during the end-systolic quiescent period was preferable as it coincided with the maximum size of the coronary veins. (c) 2007 Wiley-Liss, Inc.

  5. Multiple Image Arrangement for Subjective Quality Assessment

    Science.gov (United States)

    Wang, Yan; Zhai, Guangtao

    2017-12-01

    Subjective quality assessment serves as the foundation for almost all visual quality related researches. Size of the image quality databases has expanded from dozens to thousands in the last decades. Since each subjective rating therein has to be averaged over quite a few participants, the ever-increasing overall size of those databases calls for an evolution of existing subjective test methods. Traditional single/double stimulus based approaches are being replaced by multiple image tests, where several distorted versions of the original one are displayed and rated at once. And this naturally brings upon the question of how to arrange those multiple images on screen during the test. In this paper, we answer this question by performing subjective viewing test with eye tracker for different types arrangements. Our research indicates that isometric arrangement imposes less duress on participants and has more uniform distribution of eye fixations and movements and therefore is expected to generate more reliable subjective ratings.

  6. Infrared thermal facial image sequence registration analysis and verification

    Science.gov (United States)

    Chen, Chieh-Li; Jian, Bo-Lin

    2015-03-01

    To study the emotional responses of subjects to the International Affective Picture System (IAPS), infrared thermal facial image sequence is preprocessed for registration before further analysis such that the variance caused by minor and irregular subject movements is reduced. Without affecting the comfort level and inducing minimal harm, this study proposes an infrared thermal facial image sequence registration process that will reduce the deviations caused by the unconscious head shaking of the subjects. A fixed image for registration is produced through the localization of the centroid of the eye region as well as image translation and rotation processes. Thermal image sequencing will then be automatically registered using the two-stage genetic algorithm proposed. The deviation before and after image registration will be demonstrated by image quality indices. The results show that the infrared thermal image sequence registration process proposed in this study is effective in localizing facial images accurately, which will be beneficial to the correlation analysis of psychological information related to the facial area.

  7. Image enhancement and moving target detection in IR image sequences

    NARCIS (Netherlands)

    Beck, W.

    1993-01-01

    Results are presented of noise reduction by motion compensated temporal filtering in a noisy IR image sequence and of moving target detection in an air-to-ground IR image sequence. In the case of motion compensated temporal filtering our approach consists of estimating the optical flow between

  8. Retinal Image Simulation of Subjective Refraction Techniques.

    Science.gov (United States)

    Perches, Sara; Collados, M Victoria; Ares, Jorge

    2016-01-01

    Refraction techniques make it possible to determine the most appropriate sphero-cylindrical lens prescription to achieve the best possible visual quality. Among these techniques, subjective refraction (i.e., patient's response-guided refraction) is the most commonly used approach. In this context, this paper's main goal is to present a simulation software that implements in a virtual manner various subjective-refraction techniques--including Jackson's Cross-Cylinder test (JCC)--relying all on the observation of computer-generated retinal images. This software has also been used to evaluate visual quality when the JCC test is performed in multifocal-contact-lens wearers. The results reveal this software's usefulness to simulate the retinal image quality that a particular visual compensation provides. Moreover, it can help to gain a deeper insight and to improve existing refraction techniques and it can be used for simulated training.

  9. Fractal-based image sequence compression scheme

    Science.gov (United States)

    Li, Haibo; Novak, Mirek; Forchheimer, Robert

    1993-07-01

    The dominant image transformation used in the existing fractal coding schemes is the affine function. Although an affine transformation is easy to compute and understand, its linear approximation ability limits the employment of larger range blocks, that is, it limits further improvement in compression efficiency. We generalize the image transformation from the usual affine form to the more general quadratic form, and provide theoretical requirements for the generalized transformation to be contractive. Based on the self-transformation system (STS) model, an image sequence coding scheme--fractal-based image sequence coding--is proposed. In this coding scheme, our generalized transformation is used to model the self- transformation is used to model the self-transformation from the domain block to its range blocks. Experimental results on a real image sequence show that for the same size of blocks, the SNR can be improved by 10 dB, or, for the same SNR of the decoded image sequence, the compression ratio is raised twofold when the new generalized transformation is used to replace the usual affine transformation. In addition, due to the utilization of the STS model, the computational complexity is only linearly related to the size of the 3-D blocks. This provides for fast encoding and decoding.

  10. Image correlation method for DNA sequence alignment.

    Directory of Open Access Journals (Sweden)

    Millaray Curilem Saldías

    Full Text Available 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.

  11. 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

  12. 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.

  13. Open source database of images DEIMOS: extension for large-scale subjective image quality assessment

    Science.gov (United States)

    Vítek, Stanislav

    2014-09-01

    DEIMOS (Database of Images: Open Source) is an open-source database of images and video sequences for testing, verification and comparison of various image and/or video processing techniques such as compression, reconstruction and enhancement. This paper deals with extension of the database allowing performing large-scale web-based subjective image quality assessment. Extension implements both administrative and client interface. The proposed system is aimed mainly at mobile communication devices, taking into account advantages of HTML5 technology; it means that participants don't need to install any application and assessment could be performed using web browser. The assessment campaign administrator can select images from the large database and then apply rules defined by various test procedure recommendations. The standard test procedures may be fully customized and saved as a template. Alternatively the administrator can define a custom test, using images from the pool and other components, such as evaluating forms and ongoing questionnaires. Image sequence is delivered to the online client, e.g. smartphone or tablet, as a fully automated assessment sequence or viewer can decide on timing of the assessment if required. Environmental data and viewing conditions (e.g. illumination, vibrations, GPS coordinates, etc.), may be collected and subsequently analyzed.

  14. 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.

  15. Hippocampal surface deformation accuracy in T1-weighted volumetric MRI sequences in subjects with epilepsy.

    Science.gov (United States)

    Hogan, R Edward; Moseley, Emily D; Maccotta, Luigi

    2015-01-01

    To demonstrate the accuracy across different acquisition and analysis methods, we evaluated the variability in hippocampal volumetric and surface displacement measurements resulting from two different MRI (magnetic resonance imaging) acquisition protocols. Nine epilepsy patients underwent two independent T1-weighted magnetization prepared spoiled gradient sequences during a single 3T MRI session. Using high-dimension mapping-large deformation (HDM-LD) segmentation, we calculated volumetric estimates and generated a vector-based 3-dimensional surface model of each subject's hippocampi, and evaluated volume and surface changes, the latter using a cluster-based noise estimation model. Mean hippocampal volumes and standard deviations for the left hippocampi were 2,750 (826) mm3 and 2,782 (859) mm3 (P = .13), and for the right hippocampi were 2,558 (750) mm3 and 2,547 (692) mm3 (P = .76), respectively for the MPR1 and MPR2 sequences. Average Dice coefficient comparing overlap for segmentations was 86%. There was no significant effect of MRI sequence on volume estimates and no significant hippocampal surface change between sequences. Statistical comparison of hippocampal volumes and statistically thresholded HDM-LD surfaces in TLE patients showed no differences between the segmentations obtained in the two MRI acquisition sequences. This validates the robustness across MRI sequences of the HDM-LD technique for estimating volume and surface changes in subjects with epilepsy. Copyright © 2014 by the American Society of Neuroimaging.

  16. Space debris detection in optical image sequences.

    Science.gov (United States)

    Xi, Jiangbo; Wen, Desheng; Ersoy, Okan K; Yi, Hongwei; Yao, Dalei; Song, Zongxi; Xi, Shaobo

    2016-10-01

    We present a high-accuracy, low false-alarm rate, and low computational-cost methodology for removing stars and noise and detecting space debris with low signal-to-noise ratio (SNR) in optical image sequences. First, time-index filtering and bright star intensity enhancement are implemented to remove stars and noise effectively. Then, a multistage quasi-hypothesis-testing method is proposed to detect the pieces of space debris with continuous and discontinuous trajectories. For this purpose, a time-index image is defined and generated. Experimental results show that the proposed method can detect space debris effectively without any false alarms. When the SNR is higher than or equal to 1.5, the detection probability can reach 100%, and when the SNR is as low as 1.3, 1.2, and 1, it can still achieve 99%, 97%, and 85% detection probabilities, respectively. Additionally, two large sets of image sequences are tested to show that the proposed method performs stably and effectively.

  17. Disparity estimation from monocular image sequence

    Science.gov (United States)

    Zhang, Qieshi; Kamata, Sei-ichiro

    2015-02-01

    This paper proposes a novel method for estimating disparity accurately. To achieve the ideal result, an optimal adjusting framework is proposed to address the noise, occlusions, and outliners. Different from the typical multi-view stereo (MVS) methods, the proposed approach not only use the color constraint, but also use the geometric constraint associating multiple frame from the image sequence. The result shows the disparity with a good visual quality that most of the noise is eliminated, the errors in occlusion area are suppressed and the details of scene objects are preserved.

  18. Perceptual distortion measure for edgelike artifacts in image sequences

    Science.gov (United States)

    Yeh, Edmund M.; Kokaram, Anil C.; Kingsbury, Nick G.

    1998-07-01

    This paper presents an objective perceptual distortion measure quantifying the visibility of edge-like blocking artifacts in coded image sequences resulting from popular transform coding techniques. The prime motivation for this work is the awareness that properties of the human visual system should be central to the design and evaluation of image coding algorithms. The perceptual metric is the output of a visual model incorporating both the spatial and temporal characteristics of the visual system. Parameters of the model are based on results from a number of visual experiments in which sensitivities to simulated blocking artifacts were measured under various spatio-temporal background conditions. The visual model takes a pair of original and distorted sequences as inputs. Distortions are calculated along the vertical and horizontal directions. Visibility dependencies on spatial, temporal and motion activities of the background are incorporated using linear filtering and motion estimation. Pixel-based distortions are combined over local spatial and temporal regions to generate an overall distortion measure for each orientation. The final model output is the sum of the vertical and horizontal distortion measures. The model was applied to coded image sequences and the resulting distortion measures were compared to outcomes of subjective ranking tests. Results indicate that the perceptual distortion measure agrees well with human evaluation.

  19. Interpolation of missing data in image sequences.

    Science.gov (United States)

    Kokaram, A C; Morris, R D; Fitzgerald, W J; Rayner, P W

    1995-01-01

    This paper presents a number of model based interpolation schemes tailored to the problem of interpolating missing regions in image sequences. These missing regions may be of arbitrary size and of random, but known, location. This problem occurs regularly with archived film material. The film is abraded or obscured in patches, giving rise to bright and dark flashes, known as "dirt and sparkle" in the motion picture industry. Both 3-D autoregressive models and 3-D Markov random fields are considered in the formulation of the different reconstruction processes. The models act along motion directions estimated using a multiresolution block matching scheme. It is possible to address this sort of impulsive noise suppression problem with median filters, and comparisons with earlier work using multilevel median filters are performed. These comparisons demonstrate the higher reconstruction fidelity of the new interpolators.

  20. A multi-plane scout sequence using flash imaging.

    Science.gov (United States)

    Wright, S M; Wright, R M

    1988-01-01

    A new pulse sequence is presented for multi-plane imaging which simultaneously acquires images in the axial, coronal, and sagittal planes. Combined with FLASH imaging or other similar techniques, T1- and T2-weighted images in all three planes can be acquired in approximately 12 and 30 seconds, respectively. The sequence is easily implemented by modifying a multi-slice sequence to provide a rotation of gradient assignments between slice excitations. This sequence has been used extensively as a rapid "scout" scan. Several clinical examples are included.

  1. Objective and Subjective Assessment of Digital Pathology Image Quality

    Directory of Open Access Journals (Sweden)

    Prarthana Shrestha

    2015-03-01

    Full Text Available The quality of an image produced by the Whole Slide Imaging (WSI scanners is of critical importance for using the image in clinical diagnosis. Therefore, it is very important to monitor and ensure the quality of images. Since subjective image quality assessments by pathologists are very time-consuming, expensive and difficult to reproduce, we propose a method for objective assessment based on clinically relevant and perceptual image parameters: sharpness, contrast, brightness, uniform illumination and color separation; derived from a survey of pathologists. We developed techniques to quantify the parameters based on content-dependent absolute pixel performance and to manipulate the parameters in a predefined range resulting in images with content-independent relative quality measures. The method does not require a prior reference model. A subjective assessment of the image quality is performed involving 69 pathologists and 372 images (including 12 optimal quality images and their distorted versions per parameter at 6 different levels. To address the inter-reader variability, a representative rating is determined as a one-tailed 95% confidence interval of the mean rating. The results of the subjective assessment support the validity of the proposed objective image quality assessment method to model the readers’ perception of image quality. The subjective assessment also provides thresholds for determining the acceptable level of objective quality per parameter. The images for both the subjective and objective quality assessment are based on the HercepTestTM slides scanned by the Philips Ultra Fast Scanners, developed at Philips Digital Pathology Solutions. However, the method is applicable also to other types of slides and scanners.

  2. Subjectivity

    Directory of Open Access Journals (Sweden)

    Jesús Vega Encabo

    2015-11-01

    Full Text Available In this paper, I claim that subjectivity is a way of being that is constituted through a set of practices in which the self is subject to the dangers of fictionalizing and plotting her life and self-image. I examine some ways of becoming subject through narratives and through theatrical performance before others. Through these practices, a real and active subjectivity is revealed, capable of self-knowledge and self-transformation. 

  3. Subjective matters: from image quality to image psychology

    Science.gov (United States)

    Fedorovskaya, Elena A.; De Ridder, Huib

    2013-03-01

    From the advent of digital imaging through several decades of studies, the human vision research community systematically focused on perceived image quality and digital artifacts due to resolution, compression, gamma, dynamic range, capture and reproduction noise, blur, etc., to help overcome existing technological challenges and shortcomings. Technological advances made digital images and digital multimedia nearly flawless in quality, and ubiquitous and pervasive in usage, provide us with the exciting but at the same time demanding possibility to turn to the domain of human experience including higher psychological functions, such as cognition, emotion, awareness, social interaction, consciousness and Self. In this paper we will outline the evolution of human centered multidisciplinary studies related to imaging and propose steps and potential foci of future research.

  4. Based on photogrammetry methodological sequence image 3D movement comparisons

    Science.gov (United States)

    Zhang, Chunsen; He, Shaojun

    2005-10-01

    The sequence image 3D movement analysis is method that estimates 3D movement parameter from 2D image sequence or 3D "image" (object side) sequence. In theory, monocular and binocular sequence image all can fulfill the three dimensions movement analyses, but there are distinctions in the complexity of computing and accuracy of computing result. In order to compare the accuracy of estimates 3D movement parameter from 2D image sequence or 3D "image" sequence, the article uses ideas of "relative orientation" and "space similitude transform" in photogrammetry for reference, presents an approach that connects the image data with real three dimensions space by making use of the result of calibration and other additional conditions to unify the computing result of monocular and binocular sequence image to object side coordinate system which origin point is one fixed point in object side, this make it possible to compare their results. The experiment results of real data, which use the method, are given.

  5. Feasibility of conductivity imaging using subject eddy currents induced by switching of MRI gradients.

    Science.gov (United States)

    Oran, Omer Faruk; Ider, Yusuf Ziya

    2017-05-01

    To investigate the feasibility of low-frequency conductivity imaging based on measuring the magnetic field due to subject eddy currents induced by switching of MRI z-gradients. We developed a simulation model for calculating subject eddy currents and the magnetic fields they generate (subject eddy fields). The inverse problem of obtaining conductivity distribution from subject eddy fields was formulated as a convection-reaction partial differential equation. For measuring subject eddy fields, a modified spin-echo pulse sequence was used to determine the contribution of subject eddy fields to MR phase images. In the simulations, successful conductivity reconstructions were obtained by solving the derived convection-reaction equation, suggesting that the proposed reconstruction algorithm performs well under ideal conditions. However, the level of the calculated phase due to the subject eddy field in a representative object indicates that this phase is below the noise level and cannot be measured with an uncertainty sufficiently low for accurate conductivity reconstruction. Furthermore, some artifacts other than random noise were observed in the measured phases, which are discussed in relation to the effects of system imperfections during readout. Low-frequency conductivity imaging does not seem feasible using basic pulse sequences such as spin-echo on a clinical MRI scanner. Magn Reson Med 77:1926-1937, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  6. Quality Assessment of Mapping Building Textures from Infrared Image Sequences

    Science.gov (United States)

    Hoegner, L.; Iwaszczuk, D.; Stilla, U.

    2012-07-01

    Generation and texturing of building models is a fast developing field of research. Several techniques have been developed to extract building geometry and textures from multiple images and image sequences. In this paper, these techniques are discussed and extended to automatically add new textures from infrared (IR) image sequences to existing building models. In contrast to existing work, geometry and textures are not generated together from the same dataset but the textures are extracted from the image sequence and matched to an existing geo-referenced 3D building model. The texture generation is divided in two main parts. The first part deals with the estimation and refinement of the exterior camera orientation. Feature points are extracted in the images and used as tie points in the sequence. A recorded exterior orientation of the camera s added to these homologous points and a bundle adjustment is performed starting on image pairs and combining the hole sequence. A given 3d model of the observed building is additionally added to introduce further constraint as ground control points in the bundle adjustment. The second part includes the extraction of textures from the images and the combination of textures from different images of the sequence. Using the reconstructed exterior camera orientation for every image of the sequence, the visible facades are projected into the image and texture is extracted. These textures normally contain only parts of the facade. The partial textures extracted from all images are combined to one facade texture. This texture is stored with a 3D reference to the corresponding facade. This allows searching for features in textures and localising those features in 3D space. It will be shown, that the proposed strategy allows texture extraction and mapping even for big building complexes with restricted viewing possibilities and for images with low optical resolution.

  7. Cross-utilizing hyperchaotic and DNA sequences for image encryption

    Science.gov (United States)

    Zhan, Kun; Wei, Dong; Shi, Jinhui; Yu, Jun

    2017-01-01

    The hyperchaotic sequence and the DNA sequence are utilized jointly for image encryption. A four-dimensional hyperchaotic system is used to generate a pseudorandom sequence. The main idea is to apply the hyperchaotic sequence to almost all steps of the encryption. All intensity values of an input image are converted to a serial binary digit stream, and the bitstream is scrambled globally by the hyperchaotic sequence. DNA algebraic operation and complementation are performed between the hyperchaotic sequence and the DNA sequence to obtain a robust encryption performance. The experiment results demonstrate that the encryption algorithm achieves the performance of the state-of-the-art methods in term of quality, security, and robustness against noise and cropping attack.

  8. Safety Assessment of Advanced Imaging Sequences I: Measurements

    DEFF Research Database (Denmark)

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

    2016-01-01

    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 tru...

  9. Fast Registration of Terrestrial LIDAR Point Cloud and Sequence Images

    Science.gov (United States)

    Shao, J.; Zhang, W.; Zhu, Y.; Shen, A.

    2017-09-01

    Image has rich color information, and it can help to promote recognition and classification of point cloud. The registration is an important step in the application of image and point cloud. In order to give the rich texture and color information for LiDAR point cloud, the paper researched a fast registration method of point cloud and sequence images based on the ground-based LiDAR system. First, calculating transformation matrix of one of sequence images based on 2D image and LiDAR point cloud; second, using the relationships of position and attitude information among multi-angle sequence images to calculate all transformation matrixes in the horizontal direction; last, completing the registration of point cloud and sequence images based on the collinear condition of image point, projective center and LiDAR point. The experimental results show that the method is simple and fast, and the stitching error between adjacent images is litter; meanwhile, the overall registration accuracy is high, and the method can be used in engineering application.

  10. Symbolic representation and visual querying of left ventricular image sequences.

    Science.gov (United States)

    Baroni, M; Del Bimbo, A; Evangelist, A; Vicario, E

    1999-01-01

    In the evaluation of regional left ventricular function, relevant cardiac disorders manifest themselves not only in static features, such as shape descriptors and motion excursion in end-diastolic and end-systolic frames, but also in their temporal evolution. In common diagnostic practice, such dynamic patterns are analysed by direct inspection of frame sequences through the use of a moviola. This permits only a subjective and poorly defined evaluation of functional parameters, and definitely prevents a systematic and reproducible analysis of large sets of reports. Retrieval by contents techniques may overcome this limitation by permitting the automatic comparison of the reports in a database against queries expressing descriptive properties related to significant pathological conditions. A system is presented which is aimed at investigating the potential of this approach by supporting retrieval by contents from a database of cineangiographic or echocardiographic images. The system relies on a symbolic description of both geometrical and temporal properties of left ventricular contours. This is derived automatically by an image processing and interpretation module and associated with the report at its storage time. In the retrieval stage, queries are expressed by means of an iconic visual language which describes searched content properties over a computer screen. The system automatically interprets iconic statements and compares them against concrete descriptions in the database. This enables medical users to interact with the system to search for motion and shape abnormalities on a regional basis, in single or homogeneous groups of reports, so as to enable both prospective and retrospective diagnosis.

  11. Vibration Response Imaging: evaluation of rater agreement in healthy subjects and subjects with pneumonia

    Directory of Open Access Journals (Sweden)

    Makris Demosthenes

    2010-03-01

    Full Text Available Abstract Background We evaluated pulmonologists variability in the interpretation of Vibration response imaging (VRI obtained from healthy subjects and patients hospitalized for community acquired pneumonia. Methods The present is a prospective study conducted in a tertiary university hospital. Twenty healthy subjects and twenty three pneumonia cases were included in this study. Six pulmonologists blindly analyzed images of normal subjects and pneumonia cases and evaluated different aspects of VRI images related to the quality of data aquisition, synchronization of the progression of breath sound distribution and agreement between the maximal energy frame (MEF of VRI (which is the maximal geographical area of lung vibrations produced at maximal inspiration and chest radiography. For qualitative assessment of VRI images, the raters' evaluations were analyzed by degree of consistency and agreement. Results The average value for overall identical evaluations of twelve features of the VRI image evaluation, ranged from 87% to 95% per rater (94% to 97% in control cases and from 79% to 93% per rater in pneumonia cases. Inter-rater median (IQR agreement was 91% (82-96. The level of agreement according to VRI feature evaluated was in most cases over 80%; intra-class correlation (ICC obtained by using a model of subject/rater for the averaged features was overall 0.86 (0.92 in normal and 0.73 in pneumonia cases. Conclusions Our findings suggest good agreement in the interpretation of VRI data between different raters. In this respect, VRI might be helpful as a radiation free diagnostic tool for the management of pneumonia.

  12. An efficient image cryptosystem based on wolfram sequence and RNS

    African Journals Online (AJOL)

    In this paper we propose a novel encryption algorithm for digital images using the moduli set {2n+2, 2n+1, 2n}. The technique uses the Wolfram sequence for resizing, bitwise-XOR for pixel scrambling and modulus operation for pixel encoding. In the proposed scheme, a digital image is first segmented into many parts.

  13. Preparation of 2D sequences of corneal images for 3D model building.

    Science.gov (United States)

    Elbita, Abdulhakim; Qahwaji, Rami; Ipson, Stanley; Sharif, Mhd Saeed; Ghanchi, Faruque

    2014-04-01

    A confocal microscope provides a sequence of images, at incremental depths, of the various corneal layers and structures. From these, medical practioners can extract clinical information on the state of health of the patient's cornea. In this work we are addressing problems associated with capturing and processing these images including blurring, non-uniform illumination and noise, as well as the displacement of images laterally and in the anterior-posterior direction caused by subject movement. The latter may cause some of the captured images to be out of sequence in terms of depth. In this paper we introduce automated algorithms for classification, reordering, registration and segmentation to solve these problems. The successful implementation of these algorithms could open the door for another interesting development, which is the 3D modelling of these sequences. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  14. Noisy images-JPEG compressed: subjective and objective image quality evaluation

    Science.gov (United States)

    Corchs, Silvia; Gasparini, Francesca; Schettini, Raimondo

    2014-01-01

    The aim of this work is to study image quality of both single and multiply distorted images. We address the case of images corrupted by Gaussian noise or JPEG compressed as single distortion cases and images corrupted by Gaussian noise and then JPEG compressed, as multiply distortion case. Subjective studies were conducted in two parts to obtain human judgments on the single and multiply distorted images. We study how these subjective data correlate with No Reference state-of-the-art quality metrics. We also investigate proper combining of No Reference metrics to achieve better performance. Results are analyzed and compared in terms of correlation coefficients.

  15. Estimation of visual motion in image sequences

    DEFF Research Database (Denmark)

    Larsen, Rasmus

    1994-01-01

    are given. In particular we have investigated the use of smoothness of the second order derivatives, and the use of edge model and prior destributions for the field that favor discontinuities to characterize the motion field. A succesful implementation of a temporal interpolation in a sequence of weather...... of motion under an assumption of translatory motion has been considered. Furthermore we have described methods for quantifying the directional certainty with which we have measured the local displacement. A method based on local estimation of the spatio temporal orientation is generalized to give...

  16. Image-based temporal alignment of echocardiographic sequences

    Science.gov (United States)

    Danudibroto, Adriyana; Bersvendsen, Jørn; Mirea, Oana; Gerard, Olivier; D'hooge, Jan; Samset, Eigil

    2016-04-01

    Temporal alignment of echocardiographic sequences enables fair comparisons of multiple cardiac sequences by showing corresponding frames at given time points in the cardiac cycle. It is also essential for spatial registration of echo volumes where several acquisitions are combined for enhancement of image quality or forming larger field of view. In this study, three different image-based temporal alignment methods were investigated. First, a method based on dynamic time warping (DTW). Second, a spline-based method that optimized the similarity between temporal characteristic curves of the cardiac cycle using 1D cubic B-spline interpolation. Third, a method based on the spline-based method with piecewise modification. These methods were tested on in-vivo data sets of 19 echo sequences. For each sequence, the mitral valve opening (MVO) time was manually annotated. The results showed that the average MVO timing error for all methods are well under the time resolution of the sequences.

  17. Images and bodies subject: sexuality in advertising campaign be stupid

    Directory of Open Access Journals (Sweden)

    Douglas Luiz Menegazzi

    2013-08-01

    Full Text Available This paper discusses the portrayal of sexuality and gender in contemporary advertising by the image and it focuses on visual analysis of the case study of the campaign Be Stupid, the clothing brand Diesel. Examines some of the ads clearer suggestions to the theme of sexuality, about fifteen images, running between 2010 and 2011em many countries, including Brazil, having won the controversial impact of media such as magazines, billboards and especially the Internet. Perform a survey of theoretical and methodological aspects that facilitate the action of reading and deciphering the images, mainly based on the theory Flusser conceptions of technical image, apparatus, with a view to focus on media production, broadcasting, and formats distribution. These advertising images as visual anthropological objects who discourse through the triad body, image and media conditions of power and surveillance, eroticism, stereotypes and cultural life of the spectacle. Contextualizes the scenario analysis within the postmodern perspective, the society of advanced capitalism and diffuse power and media, marked by profound changes in the scale of the feeling of their individual identities unstable. With an emphasis on Foucauldian theory, discusses the concepts of identity, gender intelligible and cultural practices of subjection of the individual mechanisms for language and sexuality. Discusses how is the construction of visual messages of sexuality and gender roles specified by the images and search on it, demonstrating the wider aspects of visual advertising messages today.

  18. 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.

  19. 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.

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

    Science.gov (United States)

    Caron, James N; Montes, Marcos J; Obermark, Jerome L

    2016-06-01

    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. Safety Assessment of Advanced Imaging Sequences I: Measurements.

    Science.gov (United States)

    Jensen, Jorgen Arendt; Rasmussen, Morten Fischer; Pihl, Michael Johannes; Holbek, Simon; Hoyos, Carlos Armando Villagómez; Bradway, David P; Stuart, Matthias Bo; Tomov, Borislav Gueorguiev

    2016-01-01

    A method for rapid measurement of intensities (I(spta)), 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 distributions. The method is several orders of magnitude faster than approaches using an oscilloscope, and it also facilitates validating the emitted pressure field and the scanner's emission sequence software. It has been implemented using the experimental synthetic aperture real-time ultrasound system (SARUS) scanner and the Onda AIMS III intensity 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 SA duplex flow sequence. A BK8820e (BK Medical, Herlev, Denmark) convex array probe is used for the first three sequences and a BK8670 linear array probe for the SA sequence. The method is shown to give the same intensity values within 0.24% of the AIMS III Soniq 5.0 (Onda Corporation, Sunnyvale, CA, USA) commercial intensity measurement program. The approach can measure and store data for a full imaging sequence in 3.8-8.2 s per spatial position. Based on I(spta), MI, and probe surface temperature, the method gives the ability to determine whether a sequence is within U.S. FDA limits, or alternatively indicate how to scale it to be within limits.

  2. Research on hyperspectral dynamic scene and image sequence simulation

    Science.gov (United States)

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

    2016-10-01

    This paper presents a simulation method of hyper-spectral dynamic scene and image sequence for hyper-spectral equipment evaluation and target detection algorithm. Because of high spectral resolution, strong band continuity, anti-interference and other advantages, in recent years, hyper-spectral 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 hyper-spectral 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 hyper-spectral 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, hyper-spectral 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 hyper-spectral images are consistent with the theoretical analysis results.

  3. Face reconstruction from image sequences for forensic face comparison

    NARCIS (Netherlands)

    van Dam, C.; Veldhuis, Raymond N.J.; Spreeuwers, Lieuwe Jan

    2016-01-01

    The authors explore the possibilities of a dense model-free three-dimensional (3D) face reconstruction method, based on image sequences from a single camera, to improve the current state of forensic face comparison. They propose a new model-free 3D reconstruction method for faces, based on the

  4. Safety Assessment of Advanced Imaging Sequences II: Simulations

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt

    2016-01-01

    An automatic approach for simulating the emitted pressure, intensity, and MI of advanced ultrasound imaging sequences is presented. It is based on a linear simulation of pressure fields using Field II, and it is hypothesized that linear simulation can attain the needed accuracy for predicting Mec...

  5. Finding trajectories of feature points in a monocular image sequence.

    Science.gov (United States)

    Sethi, I K; Jain, R

    1987-01-01

    Identifying the same physical point in more than one image, the correspondence problem, is vital in motion analysis. Most research for establishing correspondence uses only two frames of a sequence to solve this problem. By using a sequence of frames, it is possible to exploit the fact that due to inertia the motion of an object cannot change instantaneously. By using smoothness of motion, it is possible to solve the correspondence problem for arbitrary motion of several nonrigid objects in a scene. We formulate the correspondence problem as an optimization problem and propose an iterative algorithm to find trajectories of points in a monocular image sequence. A modified form of this algorithm is useful in case of occlusion also. We demonstrate the efficacy of this approach considering synthetic, laboratory, and real scenes.

  6. Congruence analysis of point clouds from unstable stereo image sequences

    Directory of Open Access Journals (Sweden)

    C. Jepping

    2014-06-01

    Full Text Available This paper deals with the correction of exterior orientation parameters of stereo image sequences over deformed free-form surfaces without control points. Such imaging situation can occur, for example, during photogrammetric car crash test recordings where onboard high-speed stereo cameras are used to measure 3D surfaces. As a result of such measurements 3D point clouds of deformed surfaces are generated for a complete stereo sequence. The first objective of this research focusses on the development and investigation of methods for the detection of corresponding spatial and temporal tie points within the stereo image sequences (by stereo image matching and 3D point tracking that are robust enough for a reliable handling of occlusions and other disturbances that may occur. The second objective of this research is the analysis of object deformations in order to detect stable areas (congruence analysis. For this purpose a RANSAC-based method for congruence analysis has been developed. This process is based on the sequential transformation of randomly selected point groups from one epoch to another by using a 3D similarity transformation. The paper gives a detailed description of the congruence analysis. The approach has been tested successfully on synthetic and real image data.

  7. 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.

  8. Innovative anisotropic phantoms for calibration of diffusion tensor imaging sequences.

    Science.gov (United States)

    Kłodowski, Krzysztof; Krzyżak, Artur Tadeusz

    2016-05-01

    The paper describes a novel type of anisotropic phantoms designed for b-matrix spatial distribution diffusion tensor imaging (BSD-DTI). Cubic plate anisotropic phantom, cylinder capillary phantom and water reference phantom are described as a complete set necessary for calibration, validation and normalization of BSD-DTI. An innovative design of the phantoms basing on enclosing the anisotropic cores in glass balls filled with liquid made for the first time possible BSD calibration with usage of echo planar imaging (EPI) sequence. Susceptibility artifacts prone to occur in EPI sequences were visibly reduced in the central region of the phantoms. The phantoms were designed for usage in a clinical scanner's head coil, but can be scaled for other coil or scanner types. The phantoms can be also used for a pre-calibration of imaging of other types of phantoms having more specific applications. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Sequences for real-time magnetic particle imaging

    Directory of Open Access Journals (Sweden)

    Weber Matthias

    2015-09-01

    Full Text Available Magnetic Particle Imaging (MPI is a new imaging modality with the potential to be a new medical tool for angiographic diagnostics. It is capable of visualizing the spatial distribution of super-paramagnetic nanoparticles in high temporal and spatial resolution. Furthermore, the new spatial encoding scheme of a field free line (FFL promises a ten-fold higher sensitivity. So far, all know imaging devices featuring this new technique feature slow data acquisition and thus, are far away from real-time imaging capability. An actual real-time approach requires a complex field generator and an application of currents with very precise amplitude and phase. Here, we present the first implementation and calibration of a dynamic FFL field sequence enabling the acquisition of 50 MPI images per second in a mouse sized scanner.

  10. Automatic tissue segmentation of neonate brain MR Images with subject-specific atlases

    Science.gov (United States)

    Cherel, Marie; Budin, Francois; Prastawa, Marcel; Gerig, Guido; Lee, Kevin; Buss, Claudia; Lyall, Amanda; Zaldarriaga Consing, Kirsten; Styner, Martin

    2015-03-01

    Automatic tissue segmentation of the neonate brain using Magnetic Resonance Images (MRI) is extremely important to study brain development and perform early diagnostics but is challenging due to high variability and inhomogeneity in contrast throughout the image due to incomplete myelination of the white matter tracts. For these reasons, current methods often totally fail or give unsatisfying results. Furthermore, most of the subcortical midbrain structures are misclassified due to a lack of contrast in these regions. We have developed a novel method that creates a probabilistic subject-specific atlas based on a population atlas currently containing a number of manually segmented cases. The generated subject-specific atlas is sharp and adapted to the subject that is being processed. We then segment brain tissue classes using the newly created atlas with a single-atlas expectation maximization based method. Our proposed method leads to a much lower failure rate in our experiments. The overall segmentation results are considerably improved when compared to using a non-subject-specific, population average atlas. Additionally, we have incorporated diffusion information obtained from Diffusion Tensor Images (DTI) to improve the detection of white matter that is not visible at this early age in structural MRI (sMRI) due to a lack of myelination. Although this necessitates the acquisition of an additional sequence, the diffusion information improves the white matter segmentation throughout the brain, especially for the mid-brain structures such as the corpus callosum and the internal capsule.

  11. Radar image sequence analysis of inhomogeneous water surfaces

    Science.gov (United States)

    Seemann, Joerg; Senet, Christian M.; Dankert, Heiko; Hatten, Helge; Ziemer, Friedwart

    1999-10-01

    The radar backscatter from the ocean surface, called sea clutter, is modulated by the surface wave field. A method was developed to estimate the near-surface current, the water depth and calibrated surface wave spectra from nautical radar image sequences. The algorithm is based on the three- dimensional Fast Fourier Transformation (FFT) of the spatio- temporal sea clutter pattern in the wavenumber-frequency domain. The dispersion relation is used to define a filter to separate the spectral signal of the imaged waves from the background noise component caused by speckle noise. The signal-to-noise ratio (SNR) contains information about the significant wave height. The method has been proved to be reliable for the analysis of homogeneous water surfaces in offshore installations. Radar images are inhomogeneous because of the dependency of the image transfer function (ITF) on the azimuth angle between the wave propagation and the antenna viewing direction. The inhomogeneity of radar imaging is analyzed using image sequences of a homogeneous deep-water surface sampled by a ship-borne radar. Changing water depths in shallow-water regions induce horizontal gradients of the tidal current. Wave refraction occurs due to the spatial variability of the current and water depth. These areas cannot be investigated with the standard method. A new method, based on local wavenumber estimation with the multiple-signal classification (MUSIC) algorithm, is outlined. The MUSIC algorithm provides superior wavenumber resolution on local spatial scales. First results, retrieved from a radar image sequence taken from an installation at a coastal site, are presented.

  12. Segmentation of medical image sequence by parallel active contour.

    Science.gov (United States)

    Fekir, Abdelkader; Benamrane, Nacéra

    2011-01-01

    This paper presents an original approach for detecting and tracking of objects in medical image sequence. We propose a multi-agent system (MAS) based on NetLogo platform for implementing parametric contour active model or snake. In NetLogo, mobile agents (turtles) move over a grid of stationary agents (patches). In our proposed MAS, each mobile agent represents a point of snake (snaxel) and it minimizes, in parallel with other turtles, the energy functional attached to its snaxel. Then, these turtles move over the image represented by a grid of patches. The set of these agents is supervised by Observer, the NetLogo global agent. In addition, Observer loads successively the frames of sequence and initializes the turtles in the first frame. The efficiency of our system is shown through some experimental results.

  13. Analysis of the cryptography security and steganography in images sequences

    OpenAIRE

    Fábio Borges de Oliveira

    2007-01-01

    Information security is being considered of great importance to the private and governamental institutions. For this reason, we opted to conduct a study of security in this dissertation. We started with an introduction to the information theory, and then we proposed a new kind of Perfect Secrecy cryptographic and finally made a study of steganography in an image sequence, in which we suggest a more aggressive steganography in coefficients of the discrete cosine transform. A segurança da in...

  14. Quality evaluation of edge detection in a road image sequences

    Directory of Open Access Journals (Sweden)

    Rodrigo B. de A. Gallis

    2004-12-01

    Full Text Available Terrestrial mobile mapping systems map interest features along roads such as poles, traffic signs, curb lines, garbage cans etc. The lab work, concerned to the object reconstruction, consists of transforming the video into still images on which homologous points and features of the road sequence are selected and measured. By means of photogrammetric intersection the object coordinates of these features and points are computed for 3D reconstruction. Using Canny algorithm for the automatic edge detection in a road image sequence the article initially focuses on the empiric determination of the required parameters (standard deviation s and high Ta and low Tb threshold. Then it presents the quality in terms of displacement of the automatically detected edges similar to those visually (manually selected straight features extracted by a human operator that takes them as correct, therefore, as reference for the automatic extraction comparison and the quality evaluation. The results of the tests are discussed and show that the quality of the automatic detection – measured by a quantity of rights and wrongs – vary accordingly to the empirically determined standard deviation and high and low thresholds and also to the image sequence environment (street or road.

  15. Ultrasound fusion image error correction using subject-specific liver motion model and automatic image registration.

    Science.gov (United States)

    Yang, Minglei; Ding, Hui; Zhu, Lei; Wang, Guangzhi

    2016-12-01

    Ultrasound fusion imaging is an emerging tool and benefits a variety of clinical applications, such as image-guided diagnosis and treatment of hepatocellular carcinoma and unresectable liver metastases. However, respiratory liver motion-induced misalignment of multimodal images (i.e., fusion error) compromises the effectiveness and practicability of this method. The purpose of this paper is to develop a subject-specific liver motion model and automatic registration-based method to correct the fusion error. An online-built subject-specific motion model and automatic image registration method for 2D ultrasound-3D magnetic resonance (MR) images were combined to compensate for the respiratory liver motion. The key steps included: 1) Build a subject-specific liver motion model for current subject online and perform the initial registration of pre-acquired 3D MR and intra-operative ultrasound images; 2) During fusion imaging, compensate for liver motion first using the motion model, and then using an automatic registration method to further correct the respiratory fusion error. Evaluation experiments were conducted on liver phantom and five subjects. In the phantom study, the fusion error (superior-inferior axis) was reduced from 13.90±2.38mm to 4.26±0.78mm by using the motion model only. The fusion error further decreased to 0.63±0.53mm by using the registration method. The registration method also decreased the rotation error from 7.06±0.21° to 1.18±0.66°. In the clinical study, the fusion error was reduced from 12.90±9.58mm to 6.12±2.90mm by using the motion model alone. Moreover, the fusion error decreased to 1.96±0.33mm by using the registration method. The proposed method can effectively correct the respiration-induced fusion error to improve the fusion image quality. This method can also reduce the error correction dependency on the initial registration of ultrasound and MR images. Overall, the proposed method can improve the clinical practicability of

  16. Non-rigid consistent registration of 2D image sequences

    Energy Technology Data Exchange (ETDEWEB)

    Arganda-Carreras, I; Sorzano, C O S; Marabini, R; Carazo, J M [Biocomputing Unit, National Centre for Biotechnology, CSIC, Darwin 3, Universidad Autonoma de Madrid, 28049 Madrid (Spain); Thevenaz, P [Biomedical Imaging Group, Ecole polytechnique federale de Lausanne (EPFL) (Switzerland); Munoz-Barrutia, A; Ortiz-de Solorzano, C [Cancer Imaging Laboratory, Centre for Applied Medical Research, University of Navarra, Pamplona (Spain); Kybic, J, E-mail: iarganda@cnb.csic.e [Center for Machine Perception, Czech Technical University, Prague (Czech Republic)

    2010-10-21

    We present a novel algorithm for the registration of 2D image sequences that combines the principles of multiresolution B-spline-based elastic registration and those of bidirectional consistent registration. In our method, consecutive triples of images are iteratively registered to gradually extend the information through the set of images of the entire sequence. The intermediate results are reused for the registration of the following triple. We choose to interpolate the images and model the deformation fields using B-spline multiresolution pyramids. Novel boundary conditions are introduced to better characterize the deformations at the boundaries. In the experimental section, we quantitatively show that our method recovers from barrel/pincushion and fish-eye deformations with subpixel error. Moreover, it is more robust against outliers-occasional strong noise and large rotations-than the state-of-the-art methods. Finally, we show that our method can be used to realign series of histological serial sections, which are often heavily distorted due to folding and tearing of the tissues.

  17. Non-rigid consistent registration of 2D image sequences

    Science.gov (United States)

    Arganda-Carreras, I.; Sorzano, C. O. S.; Thévenaz, P.; Muñoz-Barrutia, A.; Kybic, J.; Marabini, R.; Carazo, J. M.; Ortiz-de Solorzano, C.

    2010-10-01

    We present a novel algorithm for the registration of 2D image sequences that combines the principles of multiresolution B-spline-based elastic registration and those of bidirectional consistent registration. In our method, consecutive triples of images are iteratively registered to gradually extend the information through the set of images of the entire sequence. The intermediate results are reused for the registration of the following triple. We choose to interpolate the images and model the deformation fields using B-spline multiresolution pyramids. Novel boundary conditions are introduced to better characterize the deformations at the boundaries. In the experimental section, we quantitatively show that our method recovers from barrel/pincushion and fish-eye deformations with subpixel error. Moreover, it is more robust against outliers—occasional strong noise and large rotations—than the state-of-the-art methods. Finally, we show that our method can be used to realign series of histological serial sections, which are often heavily distorted due to folding and tearing of the tissues.

  18. Safety Assessment of Advanced Imaging Sequences II: Simulations.

    Science.gov (United States)

    Jensen, Jørgen Arendt

    2016-01-01

    An automatic approach for simulating the emitted pressure, intensity, and mechanical index (MI) of advanced ultrasound imaging sequences is presented. It is based on a linear simulation of pressure fields using Field II, and it is hypothesized that linear simulation can attain the needed accuracy for predicting MI and I(spta.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 nonlinear fields. The simulation time is between 0.67 and 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% and 52.3% and for I(spta.3) between -38.6% and 62.6%, when using the impulse response of the probe estimated from an independent measurement. The accuracy is increased to between -22% and 24.5% for MI and between -33.2% and 27.0% for I(spta.3), when using the pressure response measured at a single point to scale the simulation. The spatial distribution of MI and I(ta.3) closely matches that for the measurement, and simulations can, therefore, be used to select the region for measuring the intensities, resulting in a significant reduction in measurement time. It can validate emission sequences by showing symmetry of emitted pressure fields, focal position, and intensity distribution.

  19. Silhouette extraction from human gait images sequence using cosegmentation

    Science.gov (United States)

    Chen, Jinyan; Zhang, Yi

    2012-11-01

    Gait based human identification is very useful for automatic person recognize through visual surveillance and has attracted more and more researchers. A key step in gait based human identification is to extract human silhouette from images sequence. Current silhouette extraction methods are mainly based on simple color subtraction. These methods have a very poor performance when the color of some body parts is similar to the background. In this paper a cosegmentation based human silhouette extraction method is proposed. Cosegmentation is typically defined as the task of jointly segmenting "something similar" in a given set of images. We can divide the human gait images sequence into several step cycles and every step cycle consist of 10-15 frames. The frames in human gait images sequence have following similarity: every frame is similar to the next or previous frame; every frame is similar to the corresponding frame in the next or previous step cycle; every pixel can find similar pixel in other frames. The progress of cosegmentation based human silhouette extraction can be described as follows: Initially only points which have high contrast to background are used as foreground kernel points, the points in the background are used as background kernel points, then points similar to foreground points will be added to foreground points set and the points similar to background points will be added to background points set. The definition of the similarity consider the context of the point. Experimental result shows that our method has a better performance comparing to traditional human silhouette extraction methods. Keywords: Human gait

  20. 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....

  1. Outward-looking circular motion analysis of large image sequences.

    Science.gov (United States)

    Jiang, Guang; Wei, Yichen; Quan, Long; Tsui, Hung-tat; Shum, Heung Yeung

    2005-02-01

    This paper presents a novel and simple method of analyzing the motion of a large image sequence captured by a calibrated outward-looking video camera moving on a circular trajectory for large-scale environment applications. Previous circular motion algorithms mainly focus on inward-looking turntable-like setups. They are not suitable for outward-looking motion where the conic trajectory of corresponding points degenerates to straight lines. The circular motion of a calibrated camera essentially has only one unknown rotation angle for each frame. The motion recovery for the entire sequence computes only one fundamental matrix of a pair of frames to extract the angular motion of the pair using Laguerre's formula and then propagates the computation of the unknown rotation angles to the other frames by tracking one point over at least three frames. Finally, a maximum-likelihood estimation is developed for the optimization of the whole sequence. Extensive experiments demonstrate the validity of the method and the feasibility of the application in image-based rendering.

  2. Evaluating auditory stream segregation of SAM tone sequences by subjective and objective psychoacoustical tasks, and brain activity

    Directory of Open Access Journals (Sweden)

    Lena-Vanessa eDollezal

    2014-06-01

    Full Text Available Auditory stream segregation refers to a segregated percept of signal streams with different acoustic features. Different approaches have been pursued in studies of stream segregation. In psychoacoustics, stream segregation has mostly been investigated with a subjective task asking the subjects to report their percept. Few studies have applied an objective task in which stream segregation is evaluated indirectly by determining thresholds for a percept that depends on whether auditory streams are segregated or not. Furthermore, both perceptual measures and physiological measures of brain activity have been employed but only little is known about their relation. How the results from different tasks and measures are related is evaluated in the present study using examples relying on the ABA- stimulation paradigm that apply the same stimuli. We presented A and B signals that were sinusoidally amplitude modulated (SAM tones providing purely temporal, spectral or both types of cues to evaluate perceptual stream segregation and its physiological correlate. Which types of cues are most prominent was determined by the choice of carrier and modulation frequencies (fmod of the signals. In the subjective task subjects reported their percept and in the objective task we measured their sensitivity for detecting time-shifts of B signals in an ABA- sequence. As a further measure of processes underlying stream segregation we employed functional magnetic resonance imaging (fMRI. SAM tone parameters were chosen to evoke an integrated (1-stream, a segregated (2-stream or an ambiguous percept by adjusting the fmod difference between A and B tones (∆fmod. The results of both psychoacoustical tasks are significantly correlated. BOLD responses in fMRI depend on ∆fmod between A and B SAM tones. The effect of ∆fmod, however, differs between auditory cortex and frontal regions suggesting differences in representation related to the degree of perceptual ambiguity of

  3. 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...... a random variable can be decomposed into a sequence of binary decisions, each of which is coded using optimal context quantization designed for the corresponding binary random variable. This optimized coding scheme is applied to digital maps and /spl alpha-/plane sequences. The proposed optimal context...

  4. Dynamical Segmentation of the Left Ventricle in Echocardiographic Image Sequences

    Science.gov (United States)

    2001-10-25

    1 DYNAMICAL SEGMENTATION OF THE LEFT VENTRICLE IN ECHOCARDIOGRAPHIC IMAGE SEQUENCES A. Bosnjak1,2, V. Burdin 1, V. Torrealba 2, G. Montilla 2, B...V, Bosnjak A, Acuña M, Hernández L, Roux C, Montilla G. “3D Dynamics Echocardiography. Workstation for the Acquisition, Reconstruction and...Torrealba V., Hernández L., Acuña M., Montilla G., Bosnjak A., Roux C. “Interpolación Espacial de Imágenes Médicas 3D basada en movimiento”. Avances

  5. Comparison of optical flow algorithms performance on flame image sequences

    Science.gov (United States)

    Tanaś, J.; Kotyra, A.

    2017-08-01

    Analyzing flame image sequences of co-combusting pulverized coal and biomass can be used to determine the state of this very complex process. Considering dynamic changes between successive frames of such video streams the optical flow algorithms could be applied for di-agnostic purposes. The paper discusses effectiveness and performance of two approaches (sparse and dense optical flow) applied for several video streams of co-combusting biomass and pulverized coal, recorded with different combustion settings with a high-speed camera at the laboratory stand.

  6. LUM Smoother with Smooth Control for Noisy Image Sequences

    Directory of Open Access Journals (Sweden)

    Lukàč Rastislav

    2001-01-01

    Full Text Available This paper focuses on adaptive structure of LUM (lower-upper-middle smoothers for noisy image sequences. For the balance between noise suppression and signal-detail preservation, the LUM smoothers are widely used in smoothing applications. The amount of smoothing done by LUM smoothers is controlled by tuning parameter. However, the smoothing level is fixed for whole image. Thus, the excessive or insufficient smoothing can be performed. This problem is solved by a new method based on the adaptive controlled level of smoothing. A new method has excellent performance of the noise reduction in the environments corrupted by the impulse noise. In addition, minimal signal-detail and motion blurring can be observed. The performance of proposed method is evaluated through objective criteria and compared with traditional temporal, spatial, and spatiotemporal LUM smoothers.

  7. 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 Impact factor: 2.773, year: 2016

  8. A phase field method for joint denoising, edge detection, and motion estimation in image sequence processing

    NARCIS (Netherlands)

    Preusser, T.; Droske, M.; Garbe, C. S.; Telea, A.; Rumpf, M.

    2007-01-01

    The estimation of optical flow fields from image sequences is incorporated in a Mumford-Shah approach for image denoising and edge detection. Possibly noisy image sequences are considered as input and a piecewise smooth image intensity, a piecewise smooth motion field, and a joint discontinuity set

  9. [Images of Alu-sequence in 7 DNA clones from the human genome].

    Science.gov (United States)

    Korotkov, E V

    1987-01-01

    Information theory methods were used for computer search of Alu-like sequences in human DNA and RNA. Eight new regions related to the Alu repeat sequence was revealed in 85 clones from the EMBL-5 data bank. Some of these regions are purine-pyrimidine images of Alu repeats sequence, the rest are more complex images of Alu repeat sequence. A new definition for the likeness of different sequences--information image of sequence--was introduced. This information theory application greatly increases the power of DNA sequences computer analysis.

  10. The wide genetic landscape of clinical frontotemporal dementia: systematic combined sequencing of 121 consecutive subjects.

    Science.gov (United States)

    Blauwendraat, Cornelis; Wilke, Carlo; Simón-Sánchez, Javier; Jansen, Iris E; Reifschneider, Anika; Capell, Anja; Haass, Christian; Castillo-Lizardo, Melissa; Biskup, Saskia; Maetzler, Walter; Rizzu, Patrizia; Heutink, Peter; Synofzik, Matthis

    2017-07-27

    PurposeTo define the genetic spectrum and relative gene frequencies underlying clinical frontotemporal dementia (FTD).MethodsWe investigated the frequencies and mutations in neurodegenerative disease genes in 121 consecutive FTD subjects using an unbiased, combined sequencing approach, complemented by cerebrospinal fluid Aβ1-42 and serum progranulin measurements. Subjects were screened for C9orf72 repeat expansions, GRN and MAPT mutations, and, if negative, mutations in other neurodegenerative disease genes, by whole-exome sequencing (WES) (n = 108), including WES-based copy-number variant (CNV) analysis.ResultsPathogenic and likely pathogenic mutations were identified in 19% of the subjects, including mutations in C9orf72 (n = 8), GRN (n = 7, one 11-exon macro-deletion) and, more rarely, CHCHD10, TARDBP, SQSTM1 and UBQLN2 (each n = 1), but not in MAPT or TBK1. WES also unraveled pathogenic mutations in genes not commonly linked to FTD, including mutations in Alzheimer (PSEN1, PSEN2), lysosomal (CTSF, 7-exon macro-deletion) and cholesterol homeostasis pathways (CYP27A1).ConclusionOur unbiased approach reveals a wide genetic spectrum underlying clinical FTD, including 11% of seemingly sporadic FTD. It unravels several mutations and CNVs in genes and pathways hitherto not linked to FTD. This suggests that clinical FTD might be the converging downstream result of a delicate susceptibility of frontotemporal brain networks to insults in various pathways.Genetics in Medicine advance online publication, 27 July 2017; doi:10.1038/gim.2017.102.

  11. Experience with magnetic resonance imaging of human subjects with passive implants and tattoos at 7 T: a retrospective study.

    Science.gov (United States)

    Noureddine, Yacine; Bitz, Andreas K; Ladd, Mark E; Thürling, Markus; Ladd, Susanne C; Schaefers, Gregor; Kraff, Oliver

    2015-12-01

    Over the last decade, the number of clinical MRI studies at 7 T has increased dramatically. Since only limited information about the safety of implants/tattoos is available at 7 T, many centers either conservatively exclude all subjects with implants/tattoos or have started to perform dedicated tests for selected implants. This work presents our experience in imaging volunteers with implants/tattoos at 7 T over the last seven and a half years. 1796 questionnaires were analyzed retrospectively to identify subjects with implants/tattoos imaged at 7 T. For a total of 230 subjects, the type of local transmit/receive RF coil used for examination, imaging sequences, acquisition time, and the type of implants/tattoos and their location with respect to the field of view were documented. These subjects had undergone examination after careful consideration by an internal safety panel consisting of three experts in MR safety and physics. None of the subjects reported sensations of heat or force before, during, or after the examination. None expressed any discomfort related to implants/tattoos. Artifacts were reported in 52% of subjects with dental implants; all artifacts were restricted to the mouth area and did not affect image quality in the brain parenchyma. Our initial experience at 7 T indicates that a strict rejection of subjects with tattoos and/or implants is not justified. Imaging can be conditionally performed in carefully selected subjects after collection of substantial safety information and evaluation of the detailed exposure scenario (RF coil/type and position of implant). Among the assessed subjects with tattoos, no side effects from the exposure to 7 T MRI were reported.

  12. Probabilistic multi-person localisation and tracking in image sequences

    Science.gov (United States)

    Klinger, T.; Rottensteiner, F.; Heipke, C.

    2017-05-01

    The localisation and tracking of persons in image sequences in commonly guided by recursive filters. Especially in a multi-object tracking environment, where mutual occlusions are inherent, the predictive model is prone to drift away from the actual target position when not taking context into account. Further, if the image-based observations are imprecise, the trajectory is prone to be updated towards a wrong position. In this work we address both these problems by using a new predictive model on the basis of Gaussian Process Regression, and by using generic object detection, as well as instance-specific classification, for refined localisation. The predictive model takes into account the motion of every tracked pedestrian in the scene and the prediction is executed with respect to the velocities of neighbouring persons. In contrast to existing methods our approach uses a Dynamic Bayesian Network in which the state vector of a recursive Bayes filter, as well as the location of the tracked object in the image, are modelled as unknowns. This allows the detection to be corrected before it is incorporated into the recursive filter. Our method is evaluated on a publicly available benchmark dataset and outperforms related methods in terms of geometric precision and tracking accuracy.

  13. Diffusion tensor magnetic resonance imaging for single subject diagnosis in neurodegenerative diseases

    National Research Council Canada - National Science Library

    Sajjadi, Seyed A; Acosta-Cabronero, Julio; Patterson, Karalyn; Diaz-de-Grenu, Lara Z; Williams, Guy B; Nestor, Peter J

    2013-01-01

    .... This report presents evidence to indicate that corticobasal degeneration and progressive supranuclear palsy, in particular, might be identifiable at a single subject level with diffusion tensor imaging...

  14. The genealogy of sequences containing multiple sites subject to strong selection in a subdivided population.

    Science.gov (United States)

    Nordborg, Magnus; Innan, Hideki

    2003-03-01

    A stochastic model for the genealogy of a sample of recombining sequences containing one or more sites subject to selection in a subdivided population is described. Selection is incorporated by dividing the population into allelic classes and then conditioning on the past sizes of these classes. The past allele frequencies at the selected sites are thus treated as parameters rather than as random variables. The purpose of the model is not to investigate the dynamics of selection, but to investigate effects of linkage to the selected sites on the genealogy of the surrounding chromosomal region. This approach is useful for modeling strong selection, when it is natural to parameterize the past allele frequencies at the selected sites. Several models of strong balancing selection are used as examples, and the effects on the pattern of neutral polymorphism in the chromosomal region are discussed. We focus in particular on the statistical power to detect balancing selection when it is present.

  15. Images and bodies subject: sexuality in advertising campaign be stupid

    National Research Council Canada - National Science Library

    Douglas Luiz Menegazzi

    2013-01-01

    This paper discusses the portrayal of sexuality and gender in contemporary advertising by the image and it focuses on visual analysis of the case study of the campaign Be Stupid, the clothing brand Diesel...

  16. Submillimeter Imaging of Dust Around Main Sequence Stars

    Science.gov (United States)

    Jewitt, David

    1998-01-01

    This grant was to image circumstellar dust disks surrounding main-sequence stars. The delivery of the SCUBA detector we had planned to use for this work was delayed repeatedly, leading us to undertake a majority of the observations with the UKT14 submillimeter detector at the JCMT (James Clerk Maxwell Telescope) and optical imagers and a coronagraph at the University of Hawaii 2.2-m telescope. Major findings under this grant include: (1) We discovered 5 asymmetries in the beta Pictoris regenerated dust disk. The discovery of these asymmetries was a surprise, since smearing due to Keplerian shear should eliminate most such features on timescales of a few thousand years. One exception is the "wing tilt" asymmetry, which we interpret as due to the scattering phase function of dust disk particles. From the wing tilt and a model of the phase function, we find a disk plane inclination to the line of sight of JCMT). It is possible, for instance, that the main 850 micro-m blob is merely a galaxy or other high-z source projected onto the beta Pic mid-plane.

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

    Energy Technology Data Exchange (ETDEWEB)

    Park, Kwang Bo; Lee, Moon Gyu; Lim, Tae Hwan; Jeong, Yoong Ki; Ha, Hyun Kwon; Kim, Pyo Nyun; Auh, Yong Ho [Ulsan Univ. College of Medicine, Asan Medical Center, Seoul (Korea, Republic of)

    1999-11-01

    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.

  18. Destabilising the subject: examining identity through the moving image

    OpenAIRE

    Rosetzky, David

    2017-01-01

    This studio-based PhD is an enquiry into contemporary subjectivity. Through video art, it explores issues of self and how identity is informed. It questions whether or not there is an essential core to our being by examining if we are self-determined, ever-shifting, creatures of change? Or, whether we are fixed to a prescribed subject position that is wholly determined by others, cultural context and language? Through a discussion of my working methodologies including my collaboration wit...

  19. 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.

  20. Visual Images of Subjective Perception of Time in a Literary Text

    Science.gov (United States)

    Nesterik, Ella V.; Issina, Gaukhar I.; Pecherskikh, Taliya F.; Belikova, Oxana V.

    2016-01-01

    The article is devoted to the subjective perception of time, or psychological time, as a text category and a literary image. It focuses on the visual images that are characteristic of different types of literary time--accelerated, decelerated and frozen (vanished). The research is based on the assumption that the category of subjective perception…

  1. 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.

  2. Absorption spectrum of a two-level system subjected to a periodic pulse sequence

    Science.gov (United States)

    Fotso, H. F.; Dobrovitski, V. V.

    2017-06-01

    We investigate how the quantum control of a two-level system (TLS) coupled to photons can modify and tune the TLS's photon absorption spectrum. Tuning and controlling the emission and the absorption are of great interest, e.g., for the development of efficient interfaces between stationary and flying qubits in modern architectures for quantum computation and quantum communication. We consider periodic pulse control, where the TLS is subjected to a periodic sequence of the near-resonant Rabi driving pulses, each pulse implementing a 180∘ rotation. For small interpulse delays, the absorption spectrum features a pronounced peak of stimulated emission at the pulse frequency, similar satellite peaks with smaller spectral weights, and the net absorption peaks on the sides. As long as the detuning between the carrier frequency of the driving and the TLS transition frequency remains moderate, this spectral shape shows little change. Therefore, the pulse control allows shifting the absorption peak to a desired position and locks the overall absorption spectrum to the carrier frequency of the driving pulses. A detailed description of the spectrum and its evolution as a function time, the interpulse spacing, and the detuning is presented.

  3. 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...

  4. Determination of exterior parameters for video image sequences from helicopter by block adjustment with combined vertical and oblique images

    Science.gov (United States)

    Zhang, Jianqing; Zhang, Yong; Zhang, Zuxun

    2003-09-01

    Determination of image exterior parameters is a key aspect for the realization of automatic texture mapping of buildings in the reconstruction of real 3D city models. This paper reports about an application of automatic aerial triangulation on a block with three video image sequences, one vertical image sequence to buildings' roofs and two oblique image sequences to buildings' walls. A new process procedure is developed in order to auto matching homologous points between images in oblique and vertical images. Two strategies are tested. One is treating three strips as independent blocks and executing strip block adjustment respectively, the other is creating a block with three strips, using the new image matching procedure to extract large number of tie points and executing block adjustment. The block adjustment results of these two strategies are also compared.

  5. Computer Vision Tools for Finding Images and Video Sequences.

    Science.gov (United States)

    Forsyth, D. A.

    1999-01-01

    Computer vision offers a variety of techniques for searching for pictures in large collections of images. Appearance methods compare images based on the overall content of the image using certain criteria. Finding methods concentrate on matching subparts of images, defined in a variety of ways, in hope of finding particular objects. These ideas…

  6. [Body image and participation in physical activities by obese subjects].

    Science.gov (United States)

    Marcellini, Anne; Perera, Éric; Rodhain, Angélique; Férez, Sylvain

    2016-06-08

    From a sociological perspective, physical activity and diet are perceived as social and cultural practices, constructed and transmitted within human societies. The body is then thought of as a social construct, a sign and foundation of individual and collective identities. In this context, this article was designed to highlight some social processes underlying the obesity epidemic. Clarifying issues about a medical definition of obesity in an obesogenic society, and theoretical approaches to the meanings of the obesity epidemic are proposed. Individual stories of a gradual shift towards obesity are presented to illustrate the variety of trajectories that can lead to obesity in adulthood but also the variety of subjective experiences about the situation of obesity. In particular, the relationship to the body and experiences in terms of physical activity are investigated in order to understand how obesity is associated with non-commitment, low commitment or abandonment of physical activity. The issue of configurations in which commitment or re-commitments in regular exercise for sedentary populations can be possible are discussed. The discussion shows that although commitment to regular and sustainable physical activity requires a profound transformation of lifestyle for the persons concerned, the collective dimension of this change is rarely taken into account..

  7. An unsupervised approach for measuring myocardial perfusion in MR image sequences

    Science.gov (United States)

    Discher, Antoine; Rougon, Nicolas; Preteux, Francoise

    2005-08-01

    Quantitatively assessing myocardial perfusion is a key issue for the diagnosis, therapeutic planning and patient follow-up of cardio-vascular diseases. To this end, perfusion MRI (p-MRI) has emerged as a valuable clinical investigation tool thanks to its ability of dynamically imaging the first pass of a contrast bolus in the framework of stress/rest exams. However, reliable techniques for automatically computing regional first pass curves from 2D short-axis cardiac p-MRI sequences remain to be elaborated. We address this problem and develop an unsupervised four-step approach comprising: (i) a coarse spatio-temporal segmentation step, allowing to automatically detect a region of interest for the heart over the whole sequence, and to select a reference frame with maximal myocardium contrast; (ii) a model-based variational segmentation step of the reference frame, yielding a bi-ventricular partition of the heart into left ventricle, right ventricle and myocardium components; (iii) a respiratory/cardiac motion artifacts compensation step using a novel region-driven intensity-based non rigid registration technique, allowing to elastically propagate the reference bi-ventricular segmentation over the whole sequence; (iv) a measurement step, delivering first-pass curves over each region of a segmental model of the myocardium. The performance of this approach is assessed over a database of 15 normal and pathological subjects, and compared with perfusion measurements delivered by a MRI manufacturer software package based on manual delineations by a medical expert.

  8. Quantitative sodium imaging with a flexible twisted projection pulse sequence

    National Research Council Canada - National Science Library

    Lu, Aiming; Atkinson, Ian C; Claiborne, Theodore C; Damen, Frederick C; Thulborn, Keith R

    2010-01-01

    The quantification of sodium MR images from an arbitrary intensity scale into a bioscale fosters image interpretation in terms of the spatially resolved biochemical process of sodium ion homeostasis...

  9. Image motion and context: a between- and within-subjects comparison.

    Science.gov (United States)

    Simons, R F; Detenber, B H; Reiss, J E; Shults, C W

    2000-09-01

    In two previous experiments, we studied how stimulus motion affects both the self-report of emotion experience and the physiological sequelae of emotion. In both studies, image motion intensified emotional responding, and the effect of motion was relatively specific to the arousal dimension of the emotion; there was little evidence that image motion altered the valence of the image. Moving images also appeared to sustain the attention of the participants for a longer period of time than did the still images. In these two experiments, however, image motion was manipulated within participants. In the present experiment, we used a between-subjects manipulation of image motion and found a nearly identical pattern of results. These data indicate that motion inherently increments the arousal value of an image and that this increment is not dependent on the context in which motion is introduced.

  10. 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

    2017-07-21

    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; Pbody coil 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.

  11. Spatiotonal adaptivity in super-resolution of under-sampled image sequences

    NARCIS (Netherlands)

    Pham, T.Q.

    2006-01-01

    This thesis concerns the use of spatial and tonal adaptivity in improving the resolution of aliased image sequences under scene or camera motion. Each of the five content chapters focuses on a different subtopic of super-resolution: image registration (chapter 2), image fusion (chapter 3 and 4),

  12. 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

  13. 4D spiral imaging of flows in stenotic phantoms and subjects with aortic stenosis.

    Science.gov (United States)

    Negahdar, M J; Kadbi, Mo; Kendrick, Michael; Stoddard, Marcus F; Amini, Amir A

    2016-03-01

    time = 3:44 min. The conventional sequence achieved TE = 2.9 ms and scan time = 5:23 min. In subjects with aortic stenosis, we also compared both MRI methods with Doppler ultrasound (US) in the measurement of peak velocity, time to peak systolic velocity, and eject time. Bland-Altman analysis revealed that, when comparing peak velocities, the discrepancy between Doppler US and 4D spiral flow was significantly less than the discrepancy between Doppler and 4D Cartesian flow (2.75 cm/s vs. 10.25 cm/s), whereas the two MR methods were comparable (-5.75 s vs. -6 s) for time to peak. However, for the estimation of eject time, relative to Doppler US, the discrepancy for 4D conventional flow was smaller than that of 4D spiral flow (-16.25 s vs. -20 s). Relative to conventional 4D flow, 4D spiral flow achieves substantial reductions in both the TE and scan times; therefore, utility for it should be sought in a variety of in vivo and complex flow imaging applications. © 2015 Wiley Periodicals, Inc.

  14. Molecular identification of bacteria by total sequence screening: determining the cause of death in ancient human subjects.

    Directory of Open Access Journals (Sweden)

    Catherine Thèves

    Full Text Available Research of ancient pathogens in ancient human skeletons has been mainly carried out on the basis of one essential historical or archaeological observation, permitting specific pathogens to be targeted. Detection of ancient human pathogens without such evidence is more difficult, since the quantity and quality of ancient DNA, as well as the environmental bacteria potentially present in the sample, limit the analyses possible. Using human lung tissue and/or teeth samples from burials in eastern Siberia, dating from the end of 17(th to the 19(th century, we propose a methodology that includes the: 1 amplification of all 16S rDNA gene sequences present in each sample; 2 identification of all bacterial DNA sequences with a degree of identity ≥ 95%, according to quality criteria; 3 identification and confirmation of bacterial pathogens by the amplification of the rpoB gene; and 4 establishment of authenticity criteria for ancient DNA. This study demonstrates that from teeth samples originating from ancient human subjects, we can realise: 1 the correct identification of bacterial molecular sequence signatures by quality criteria; 2 the separation of environmental and pathogenic bacterial 16S rDNA sequences; 3 the distribution of bacterial species for each subject and for each burial; and 4 the characterisation of bacteria specific to the permafrost. Moreover, we identified three pathogens in different teeth samples by 16S rDNA sequence amplification: Bordetella sp., Streptococcus pneumoniae and Shigella dysenteriae. We tested for the presence of these pathogens by amplifying the rpoB gene. For the first time, we confirmed sequences from Bordetella pertussis in the lungs of an ancient male Siberian subject, whose grave dated from the end of the 17(th century to the early 18(th century.

  15. Comparing subjective and objective quality assessment of HDR images compressed with JPEG-XT

    DEFF Research Database (Denmark)

    Mantel, Claire; Ferchiu, Stefan Catalin; Forchhammer, Søren

    2014-01-01

    In this paper a subjective test in which participants evaluate the quality of JPEG-XT compressed HDR images is presented. Results show that for the selected test images and display, the subjective quality reached its saturation point starting around 3bpp. Objective evaluations are obtained by app...... the best performance with the limit that it does not capture the quality saturation. The usage of the gamma correction prior to applying metrics depends on the characteristics of each objective metric.......In this paper a subjective test in which participants evaluate the quality of JPEG-XT compressed HDR images is presented. Results show that for the selected test images and display, the subjective quality reached its saturation point starting around 3bpp. Objective evaluations are obtained...... by applying a model of the display and providing the modeled images to three objective metrics dedicated to HDR content. Objective grades are compared with subjective data both in physical domain and using a gamma correction to approximate perceptually uniform luminance coding. The MRSE metric obtains...

  16. Subjective Ratings of Beauty and Aesthetics: Correlations With Statistical Image Properties in Western Oil Paintings

    Science.gov (United States)

    Lehmann, Thomas; Redies, Christoph

    2017-01-01

    For centuries, oil paintings have been a major segment of the visual arts. The JenAesthetics data set consists of a large number of high-quality images of oil paintings of Western provenance from different art periods. With this database, we studied the relationship between objective image measures and subjective evaluations of the images, especially evaluations on aesthetics (defined as artistic value) and beauty (defined as individual liking). The objective measures represented low-level statistical image properties that have been associated with aesthetic value in previous research. Subjective rating scores on aesthetics and beauty correlated not only with each other but also with different combinations of the objective measures. Furthermore, we found that paintings from different art periods vary with regard to the objective measures, that is, they exhibit specific patterns of statistical image properties. In addition, clusters of participants preferred different combinations of these properties. In conclusion, the results of the present study provide evidence that statistical image properties vary between art periods and subject matters and, in addition, they correlate with the subjective evaluation of paintings by the participants. PMID:28694958

  17. CT image sequence restoration based on sparse and low-rank decomposition.

    Directory of Open Access Journals (Sweden)

    Shuiping Gou

    Full Text Available 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.

  18. 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.

  19. 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

    It is investigated how linear simulation can be used to predict both the magnitude of the intensities as well as the placement of the peak values. An ultrasound sequence is defined through the normal setup routines for the experimental SARUS scanner, and Field II is then used automatically on the...

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

    Energy Technology Data Exchange (ETDEWEB)

    Lavdas, E.; Zaloni, E. [Technological Education Institute of Athens, Greece, Department of Medical Radiological Technologists, Athens (Greece); Vlychou, M.; Vassiou, K.; Fezoulidis, I. [University of Thessaly, Department of Radiology, Faculty of Medicine, Larissa (Greece); Tsagkalis, A. [IASO Hospital, Department of Orthopedics, Larissa (Greece); Dailiana, Z. [University of Thessaly, Department of Orthopedics, Faculty of Medicine, Larissa (Greece)

    2015-11-15

    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.)

  1. 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.

  2. Investigating the visual inspection subjectivity on the contrast-detail evaluation in digital mammography images

    Science.gov (United States)

    Sousa, Maria A. Z.; Medeiros, Regina B.; Schiabel, Homero

    2014-03-01

    A major difficulty in the interpretation of mammographic images is the low contrast and, in the case of early detection of breast cancer, the reduced size of the features of malignancy on findings such as microcalcifications. Furthermore, image assessment is subject to significant reliance of the capacity of observation of the expert that will perform it, compromising the final diagnosis accuracy. Thinking about this aspect, this study evaluated the subjectivity of visual inspection to assess the contrast-detail in mammographic images. For this, we compared the human readings of images generated with the CDMAM phantom performed by four observers, enabling to determining a threshold of contrast visibility in each diameter disks present in the phantom. These thresholds were compared graphically and by statistical measures allowing us to build a strategy for use of contrast and detail (dimensions) as parameters of quality in mammography.

  3. Usefulness of the SPACE pulse sequence at 1.5T MR cholangiography: comparison of image quality and image acquisition time with conventional 3D-TSE sequence.

    Science.gov (United States)

    Nakaura, Takeshi; Kidoh, Masafumi; Maruyama, Natsuki; Kawahara, Tetsuya; Namimoto, Tomohiro; Sakai, Yoshinari; Harada, Kazunori; Yamashita, Yasuyuki

    2013-11-01

    To prospectively evaluate the image quality and image acquisition time at 3D magnetic resonance cholangiopancreatography (MRCP) using sampling perfection with application optimized contrasts (SPACE) and conventional turbo-spin-echo (TSE) sequences. We acquired navigator-triggered SPACE and conventional 3D-TSE MRCP images using the same parameters where possible for 30 patients and compared the image acquisition time, contrast, and contrast-to-noise ratio (CNR) of the common bile duct (CBD). Two radiologists performed qualitative analyses using a 4-point scale. Image acquisition time was 31% shorter with the SPACE than the conventional TSE sequence (248.9 ± 73.0 sec vs. 360.5 ± 99.9 sec, P TSE (39.4 ± 14.7 vs. 33.5 ± 14.2, P TSE sequence; there was a significant difference in motion artifacts and the depiction of the CBD and the left hepatic and main pancreatic duct (P TSE. Copyright © 2013 Wiley Periodicals, Inc.

  4. EEG Sequence Imaging: A Markov Prior for the Variational Garrote

    DEFF Research Database (Denmark)

    Hansen, Sofie Therese; Hansen, Lars Kai

    2013-01-01

    We propose the following generalization of the Variational Garrote for sequential EEG imaging: A Markov prior to promote sparse, but temporally smooth source dynamics. We derive a set of modied Variational Garrote updates and analyze the role of the prior's hyperparameters. An experimental...

  5. 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...

  6. Subjective quality of video sequences rendered on LCD with local backlight dimming at different lighting conditions

    DEFF Research Database (Denmark)

    Mantel, Claire; Korhonen, Jari; Pedersen, Jesper Mørkhøj

    2015-01-01

    This paper focuses on the influence of ambient light on the perceived quality of videos displayed on Liquid Crystal Display (LCD) with local backlight dimming. A subjective test assessing the quality of videos with two backlight dimming methods and three lighting conditions, i.e. no light, low...

  7. Rapid Measurements of Intensities for Safety Assessment of Advanced Imaging Sequences

    DEFF Research Database (Denmark)

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

    2014-01-01

    FDA requires that intensity and safety parameters are measured for all imaging schemes for clinical imaging. This is often cumbersome, since the scan sequence has to broken apart, measurements conducted for the individually emitted beams, and the nal intensity levels calculated by combining the i...

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

    Science.gov (United States)

    Park, Cesc; Kim, Youngjin; Kim, Gunhee

    2017-05-02

    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 22K unique blog posts with 170K 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.

  9. The concept of body image disturbance in anorexia nervosa: an empirical inquiry utilizing patients' subjective experiences.

    Science.gov (United States)

    Espeset, Ester M S; Nordbø, Ragnfrid H S; Gulliksen, Kjersti S; Skårderud, Finn; Geller, Josie; Holte, Arne

    2011-01-01

    We explored the concept body image disturbance (BID) by utilizing the subjective experience of 32 women (aged 20-39 years) diagnosed with AN (DSM-V). Using methods from Grounded Theory we identified four phenotypes of BID-"Integration," "Denial," "Dissociation," and "Delusion"-which differed according to whether the patients overestimated their own body size ("Subjective reality"), and whether they acknowledged the objective truth that they were underweight ("Objective reality"). The results suggest that BID should be conceptualized as a dynamic failure to integrate subjective experiences of one's own body appearance with an objective appraisal of the body. Conceptual, diagnostic and clinical implications are discussed.

  10. MRI-based elastic-mapping method for inter-subject comparison of brain FDG-PET images

    Energy Technology Data Exchange (ETDEWEB)

    Yang, J.; Huang, S.C.; Lin, K.P.; Small, G.; Phelps, M.E. [UCLA School of Medicine, Los Angeles, CA (United States)] [and others

    1996-12-31

    Inter-subject anatomic differences prohibits direct image-wise statistical evaluation of brain FDG-PET images of Alzheimer`s disease (AD) patients. In this study, we propose a MRI-based elastic-mapping method which enables image-wise evaluation. The method involves intra-subject MR-PET registration, 3-D elastic mapping of two set of MR images, and elastically transforming the co-registered PET images. The MR-PET registration used simulated PET images, which were based on segmentation of MR images. In the 3-D elastic mapping stage, first a global linear scaling was applied to compensate for brain size difference, then a deformation field was obtained by minimizing the regional sum of squared difference between the two sets of MR images. Two groups (AD patient and normal control), each with three subjects, were included in the current study. After processing, images from all subjects have similar shapes. Averaging the images across all subjects (either within the individual group or for both groups) give images indistinguishable from original single subject FDG images (i.e. without much spatial resolution loss), except with lower image noise level. The method is expected to allow statistical image-wise analysis to be performed across different subjects.

  11. Lossless image data sequence compression using optimal context quantization

    DEFF Research Database (Denmark)

    Forchhammer, Søren; WU, Xiaolin; Andersen, Jakob Dahl

    2001-01-01

    Context based entropy coding often faces the conflict of a desire for large templates and the problem of context dilution. We consider the problem of finding the quantizer Q that quantizes the K-dimensional causal context Ci=(X(i-t1), X(i-t2), …, X(i-tK)) of a source symbol Xi into one of M...... and context quantization for coding the binary decisions is presented and applied to digital maps and α-plane sequences. The optimal context quantization is also used to evaluate existing heuristic context quantizations....

  12. The #image and the #subject: the perception of image from Instagram

    Directory of Open Access Journals (Sweden)

    Thiago Guimarães Azevedo

    2015-06-01

    Full Text Available This paper is part of a dissertation submitted to the Graduate Program in Arts at UFPA. It aims to examine the relationship between image and memory on Instagram. Thereto, I have identified the universe of image and its interaction with the individual, by dialoguing with the modifications in regard to its constitution from the development of mobile devices such as smartphones and tablets, the most common means by which one can use Instagram. With this in mind, I have emphasized the relationship of people on social networks through these interconnection areas. However, we can perceive a path to an individualized relationship with other social actors, where the groups are assembled in a self-referential way. Thus, relationships become more fluid and less presential. The research highlights the issue of memory phenomenon beginning from the image and adopts phenomenology as its methodological approach since it represents the construction of an imaginary based on life experiences.

  13. Medical Image Processing for Fully Integrated Subject Specific Whole Brain Mesh Generation

    Directory of Open Access Journals (Sweden)

    Chih-Yang Hsu

    2015-05-01

    Full Text Available Currently, anatomically consistent segmentation of vascular trees acquired with magnetic resonance imaging requires the use of multiple image processing steps, which, in turn, depend on manual intervention. In effect, segmentation of vascular trees from medical images is time consuming and error prone due to the tortuous geometry and weak signal in small blood vessels. To overcome errors and accelerate the image processing time, we introduce an automatic image processing pipeline for constructing subject specific computational meshes for entire cerebral vasculature, including segmentation of ancillary structures; the grey and white matter, cerebrospinal fluid space, skull, and scalp. To demonstrate the validity of the new pipeline, we segmented the entire intracranial compartment with special attention of the angioarchitecture from magnetic resonance imaging acquired for two healthy volunteers. The raw images were processed through our pipeline for automatic segmentation and mesh generation. Due to partial volume effect and finite resolution, the computational meshes intersect with each other at respective interfaces. To eliminate anatomically inconsistent overlap, we utilized morphological operations to separate the structures with a physiologically sound gap spaces. The resulting meshes exhibit anatomically correct spatial extent and relative positions without intersections. For validation, we computed critical biometrics of the angioarchitecture, the cortical surfaces, ventricular system, and cerebrospinal fluid (CSF spaces and compared against literature values. Volumina and surface areas of the computational mesh were found to be in physiological ranges. In conclusion, we present an automatic image processing pipeline to automate the segmentation of the main intracranial compartments including a subject-specific vascular trees. These computational meshes can be used in 3D immersive visualization for diagnosis, surgery planning with haptics

  14. Efficacy and safety of OBI-1, an antihaemophilic factor VIII (recombinant), porcine sequence, in subjects with acquired haemophilia A.

    Science.gov (United States)

    Kruse-Jarres, R; St-Louis, J; Greist, A; Shapiro, A; Smith, H; Chowdary, P; Drebes, A; Gomperts, E; Bourgeois, C; Mo, M; Novack, A; Farin, H; Ewenstein, B

    2015-03-01

    Acquired haemophilia A (AHA) is a rare bleeding disorder caused by autoantibodies against human factor VIII (hFVIII). OBI-1 is an investigational, B-domain deleted, recombinant FVIII, porcine sequence, with low cross-reactivity to anti-hFVIII antibodies. Efficacy can be monitored with FVIII activity levels in addition to clinical assessments. This prospective, open label, phase 2/3 study was designed to evaluate the efficacy of OBI-1 treatment for bleeding episodes in subjects with AHA. After an initial dose of 200 U kg(-1) , OBI-1 was titrated to maintain target FVIII activity levels, in correlation with clinical assessments, throughout the treatment phase. All 28 subjects with AHA had a positive response to OBI-1 treatment 24 h after initiation despite inhibition of FVIII activity levels immediately after infusion in 10 subjects with baseline anti-porcine FVIII inhibitors. Control of the qualifying bleed was ultimately achieved in 24 of 28 subjects. No related serious adverse events, thrombotic events, allergic reactions or thrombocytopaenia occurred. The results of this study indicate that OBI-1 is safe and effective in treating bleeding episodes in subjects with AHA. The ability to safely and effectively titrate dosing based on FVIII activity levels in this study demonstrates that OBI-1 fulfils the unmet medical need to monitor the key coagulation parameter in AHA patients. © 2015 John Wiley & Sons Ltd.

  15. 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.

  16. 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.

  17. The sequence polymorphism of MnSOD gene in subjects with respiratory insufficiency in COPD.

    Science.gov (United States)

    Pietras, Tadeusz; Szemraj, Janusz; Witusik, Andrzej; Hołub, Monika; Panek, Michał; Wujcik, Radosław; Górski, Paweł

    2010-09-01

    Chronic obstructive pulmonary disease (COPD) is associated with the development of respiratory failure, which, in turn, exposes the tissues to oxidative stress, which is both a cause and a result of respiratory insufficiency. The first-line defense against oxidative stress is provided by the mitochondrial enzyme manganese superoxide dismutase (MnSOD), which is a superoxide anion scavenger. It is unknown whether genetic variability of the enzymes protecting against reactive oxygen species (ROS) can influence the development of respiratory failure in COPD patients. The aim of the study was to determine the correlation between polymorphism of MnSOD signal peptide and the occurrence of respiratory failure in the course of COPD. The study group consisted of 162 COPD patients (113 men and 49 women). The control group consisted of 63 subjects. Respiratory failure was diagnosed in 42 COPD patients. In all the examined subjects, the polymorphism resulting in alanine at residue 9 being replaced by valine and the expression of MnSOD in blood cells were determined. The Val/Val phenotype was demonstrated to occur in COPD patients more frequently than in the control group, as well as being associated with a lower expression level of MnSOD mRNA. Respiratory failure in the course of COPD also correlates with lower expression of MnSOD mRNA. The presence of valine at position 9 of the MnSOD signal peptide encoded by exon 2 is a risk factor for the occurrence of respiratory failure in the course of COPD in the Polish population.

  18. Periportal lymphatic system on post-hepatobiliary phase Gd-EOB-DTPA-enhanced MR imaging in normal subjects and patients with chronic hepatitis C.

    Science.gov (United States)

    Yamada, Yasunari; Matsumoto, Shunro; Mori, Hiromu; Takaji, Ryo; Kiyonaga, Maki; Hijiya, Naoki; Tanoue, Rika; Tomonari, Kenichiro; Tanoue, Shuichi; Hongo, Norio; Ohta, Masayuki; Seike, Masataka; Inomata, Masafumi; Murakami, Kazunari; Moriyama, Masatsugu

    2017-10-01

    We sought to evaluate visualization of periportal lymphatics and lymph nodes (lymphatic system) on Gd-EOB-DTPA-enhanced magnetic resonance (MR) images using a fat-suppressed T2-weighted sequence with 3-dimensional (3D) volume isotropic turbo spin echo acquisition (VISTA) at 3.0 T in normal subjects and patients with chronic hepatitis C. MR imaging was performed in 254 subjects between June 2013 and May 2016. After applying inclusion and exclusion criteria, the final population was 31 normal subjects and 34 patients with chronic hepatitis C. Images were acquired after the hepatobiliary phase following intravenous administration of Gd-EOB-DTPA, which causes signal loss in the bile ducts, to facilitate the visualization of the periportal lymphatic system. Two radiologists assessed the visualization of the periportal lymphatic system in 31 normal subjects. The axial dimensions of the main periportal lymphatic system in normal subjects were measured and compared with those of 34 patients with chronic hepatitis C using the Mann-Whitney U-test, and their correlation with a hepatic fibrosis marker, the Fibrosis-4 (FIB-4), was assessed using Spearman's rank correlation test. The periportal lymphatic system was detected as high signal intensity areas surrounding the portal vein up to the third branches by each reader in all normal subjects. The axial dimensions of the main periportal lymphatic system in patients with chronic hepatitis C were significantly larger than those in normal subjects (p system and the degree of hepatic fibrosis.

  19. Subjective and objective image differences in pediatric computed tomography cardiac angiography using lower iodine concentration

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Jae-Yeon [Pusan National University Yangsan Hospital, Department of Radiology, Yangsan-si, Gyeongsangnam-do (Korea, Republic of); Pusan National University Yangsan Hospital, Research Institute for Convergence of Biomedical Science and Technology, Yangsan-si, Gyeongsangnam-do (Korea, Republic of); Choo, Ki Seok; Choi, Yoon Young; Kim, Jin Hyeok; Ryu, Hwaseong; Kim, Yong-Woo; Jeon, Ung Bae; Nam, Kyung Jin [Pusan National University Yangsan Hospital, Department of Radiology, Yangsan-si, Gyeongsangnam-do (Korea, Republic of); Han, Junhee [Pusan National University Yangsan Hospital, Division of Biostatistics, Research Institute for Convergence of Biomedical Science and Technology, Yangsan-si, Gyeongsangnam-do (Korea, Republic of)

    2017-05-15

    Several recent studies showed the optimal contrast enhancement with a low-concentration and iso-osmolar contrast media in both adult and pediatric patients. However, low contrast media concentrations are not routinely used due to concerns of suboptimal enhancement of cardiac structures and small vessels. To evaluate the feasibility of using iso-osmolar contrast media containing a low iodine dose for CT cardiac angiography at 80 kilovolts (kVp) in neonates and infants. The iodixanol 270 group consisted of 79 CT scans and the iopromide 370 group of 62 CT scans in patients ≤1 year old. Objective measurement of the contrast enhancement was analyzed and contrast-to-noise ratios of the ascending aorta and left ventricle were calculated. Regarding subjective measurement, a four-point scale system was devised to evaluate degrees of contrast enhancement, image noise, motion artifact and overall image quality of each image set. Reader performance for correctly differentiating iodixanol 270 and iopromide 370 by visual assessment was evaluated. Group objective and subjective measurements were nonsignificantly different. Overall sensitivity, specificity and diagnostic accuracy for correctly differentiating iodixanol 270 and iopromide 370 by visual assessment were 42.8%, 59%, and 50%, respectively. The application of iodixanol 270 achieved optimal enhancement for performing pediatric cardiac CT angiography at 80 kVp in neonates and infants. Objective measurements of contrast enhancement and subjective image quality assessments were not statistically different in the iodixanol 270 and iopromide 370 groups. (orig.)

  20. The comparison of subjective image quality in conventional and digital panoramic radiography

    Directory of Open Access Journals (Sweden)

    Peker Ilkay

    2009-01-01

    Full Text Available Objective: The purpose of this study was to compare the subjective image quality of (1 regular intensifying screens with medium intensifying screens, (2 regular intensifying screens with digital radiography, and (3 medium intensifying screens with digital radiography for panoramic radiographs. Materials and Methods: Forty-five patients participated and a total of 90 radiographs were obtained in the study. The patients were divided into three groups (regular-medium intensifying screen, regular intensifying screen-digital radiography, and medium intensifying screen-digital radiography that consisted of 15 people each. All radiographs were assessed by three oral radiologists independently. The observers evaluated the images using a 3-point scale (1=well visible, 0=partly visible, -1=not or hardly visible for anatomical structures and pathological findings that are commonly found on panoramic radiographs. Subjective image quality of the groups and comparison of the observers were assessed by using non parametric Kruskal Wallis and Mann-Whitney U tests. Results: For all groups and observers, no statistically significant difference (p>0.05 was found for both anatomical structures and pathologies and between anatomical structures and pathologies according to the Mann Whitney U test. In comparison with observers, no statistically significant difference (p>0.05 was found for both anatomical structures and pathologies and between anatomical structures and pathologies for all groups according to the Kruskal Wallis test. Conclusion: The subjective image quality of medium and regular intensifying screens and conventional and digital panoramic radiographs were found statistically equal in this study.

  1. The comparison of subjective image quality in conventional and digital panoramic radiography.

    Science.gov (United States)

    Peker, Ilkay; Toraman, Alkurt M; Usalan, G; Altunkaynak, B

    2009-01-01

    The purpose of this study was to compare the subjective image quality of (1) regular intensifying screens with medium intensifying screens, (2) regular intensifying screens with digital radiography, and (3) medium intensifying screens with digital radiography for panoramic radiographs. Forty-five patients participated and a total of 90 radiographs were obtained in the study. The patients were divided into three groups (regular-medium intensifying screen, regular intensifying screen-digital radiography, and medium intensifying screen-digital radiography) that consisted of 15 people each. All radiographs were assessed by three oral radiologists independently. The observers evaluated the images using a 3-point scale (1=well visible, 0=partly visible, -1=not or hardly visible) for anatomical structures and pathological findings that are commonly found on panoramic radiographs. Subjective image quality of the groups and comparison of the observers were assessed by using non parametric Kruskal Wallis and Mann-Whitney U tests. For all groups and observers, no statistically significant difference (p>0.05) was found for both anatomical structures and pathologies and between anatomical structures and pathologies according to the Mann Whitney U test. In comparison with observers, no statistically significant difference (p>0.05) was found for both anatomical structures and pathologies and between anatomical structures and pathologies for all groups according to the Kruskal Wallis test. The subjective image quality of medium and regular intensifying screens and conventional and digital panoramic radiographs were found statistically equal in this study.

  2. Relevance of 3D magnetic resonance imaging sequences in diagnosing basal subarachnoid neurocysticercosis.

    Science.gov (United States)

    Carrillo Mezo, Roger; Lara García, Javier; Arroyo, Mariana; Fleury, Agnès

    2015-12-01

    Imagenological diagnosis of subarachnoid neurocysticercosis is usually difficult when classical magnetic resonance imaging (MRI) sequences are used. The purpose of this study was to evaluate the advantages of 3D MRI sequences (Fast Imaging Employing Steady-state Acquisition (FIESTA) and Spoiled Gradient Recalled Echo (SPGR)) with respect to classical sequences (Fluid Attenuation Inversion Recovery (FLAIR) and T1) in visualizing Taenia solium cyst in these locations. Forty-seven T. solium cysts located in the basal cisterns of the subarachnoid space were diagnosed in eighteen Mexican patients. A pre-treatment MRI was performed on all patients, and all four sequences (FIESTA, FLAIR, T1 SPGR, and T2) were evaluated independently by two neuroradiologists. The sensitivity of each sequence to detect the parasite membrane and scolex was evaluated, along with its capacity to detect differences in signal intensity between cerebrospinal fluid (CSF) and cysts. FIESTA sequences allowed the visualization of cyst membrane in 87.2% of the parasites evaluated, FLAIR in 38.3%, SPGR in 23.4%, and T2 in 17.0%. The superiority of FIESTA sequences over the other three imaging methods was statistically significant (P0.05). Differences in signal intensity between CSF and parasite cysts were significant in FIESTA (P<0.0001), SPGR (P<0.0001), and FLAIR (P=0.005) sequences. For the first time, the usefulness of 3D MRI sequences to diagnose T. solium cysts located in the basal cisterns of the subarachnoid space was demonstrated. The routine use of these sequences could favor an earlier diagnosis and greatly improve the prognosis of patients affected by this severe form of the disease. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Comparison of Computer Vision and Photogrammetric Approaches for Epipolar Resampling of Image Sequence.

    Science.gov (United States)

    Kim, Jae-In; Kim, Taejung

    2016-03-22

    Epipolar resampling is the procedure of eliminating vertical disparity between stereo images. Due to its importance, many methods have been developed in the computer vision and photogrammetry field. However, we argue that epipolar resampling of image sequences, instead of a single pair, has not been studied thoroughly. In this paper, we compare epipolar resampling methods developed in both fields for handling image sequences. Firstly we briefly review the uncalibrated and calibrated epipolar resampling methods developed in computer vision and photogrammetric epipolar resampling methods. While it is well known that epipolar resampling methods developed in computer vision and in photogrammetry are mathematically identical, we also point out differences in parameter estimation between them. Secondly, we tested representative resampling methods in both fields and performed an analysis. We showed that for epipolar resampling of a single image pair all uncalibrated and photogrammetric methods tested could be used. More importantly, we also showed that, for image sequences, all methods tested, except the photogrammetric Bayesian method, showed significant variations in epipolar resampling performance. Our results indicate that the Bayesian method is favorable for epipolar resampling of image sequences.

  4. Comparison of Computer Vision and Photogrammetric Approaches for Epipolar Resampling of Image Sequence

    Directory of Open Access Journals (Sweden)

    Jae-In Kim

    2016-03-01

    Full Text Available Epipolar resampling is the procedure of eliminating vertical disparity between stereo images. Due to its importance, many methods have been developed in the computer vision and photogrammetry field. However, we argue that epipolar resampling of image sequences, instead of a single pair, has not been studied thoroughly. In this paper, we compare epipolar resampling methods developed in both fields for handling image sequences. Firstly we briefly review the uncalibrated and calibrated epipolar resampling methods developed in computer vision and photogrammetric epipolar resampling methods. While it is well known that epipolar resampling methods developed in computer vision and in photogrammetry are mathematically identical, we also point out differences in parameter estimation between them. Secondly, we tested representative resampling methods in both fields and performed an analysis. We showed that for epipolar resampling of a single image pair all uncalibrated and photogrammetric methods tested could be used. More importantly, we also showed that, for image sequences, all methods tested, except the photogrammetric Bayesian method, showed significant variations in epipolar resampling performance. Our results indicate that the Bayesian method is favorable for epipolar resampling of image sequences.

  5. Understanding 3D TSE Sequences: Advantages, Disadvantages, and Application in MSK Imaging.

    Science.gov (United States)

    Glaser, Christian; D'Anastasi, Melvin; Theisen, Daniel; Notohamiprodjo, Mike; Horger, Wilhelm; Paul, Dominik; Horng, Annie

    2015-09-01

    Three-dimensional (3D) turbo-spin echo (TSE) sequences have outgrown the stage of mere sequence optimization and by now are clinically applicable. Image blurring and acquisition times have been reduced, and contrast for T1-, T2-, and moderately T2-weighted (or intermediate-weighted) fat-suppressed variants has been optimized. Data on sound-to-noise ratio efficiency and contrast are available for moderately T2-weighted fat-saturated sequence protocols. The 3-T MRI scanners help to better exploit isotropic spatial resolution and multiplanar reformatting. Imaging times range from 5 to 10 minutes, and they are shorter than the cumulative acquisition times of three separate orthogonal two-dimensional (2D) sequences. Recent suggestions go beyond secondary reformations by using online 3D rendering for image evaluation. Comparative clinical studies indicate that the diagnostic performance of 3D TSE for imaging of internal derangements of joints is at least comparable with conventional 2D TSE with potential advantages of 3D TSE for small highly curved structures. But such studies, especially those with direct arthroscopic correlation, are still sparse. Whether 3D TSE will succeed in entering clinical routine imaging on a broader scale will depend on further published clinical evidence, on further reduction of imaging time, and on improvement of its integration into daily practice. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  6. Microscopic imaging of slow flow and diffusion: a pulsed field gradient stimulated echo sequence combined with turbo spin echo imaging

    NARCIS (Netherlands)

    Scheenen, T.W.J.; Vergeldt, F.J.; Windt, C.W.; Jager, de P.A.; As, van H.

    2001-01-01

    In this paper we present a pulse sequence that combines a displacement-encoded stimulated echo with rapid sampling of k-space by means of turbo spin echo imaging. The stimulated echo enables the use of long observation times between the two pulsed field gradients that sample q-space completely.

  7. Noise-bound method for detecting shadow-free scene changes in image sequences.

    Science.gov (United States)

    Irie, Kenji; McKinnon, Alan; Unsworth, Keith; Woodhead, Ian

    2010-02-01

    Many image processing applications are confounded by both sensor noise and cast shadows. All image sensors add noise to a captured image that can reduce algorithm sensitivity and performance, and global filters or fixed thresholds are often applied to limit their effects. Cast shadows can appear as scene changes and are difficult to adequately detect and remove from images and image sequences. We couple image-noise statistics with a dual-illumination shadow-detection algorithm to provide a novel color-based method for shadow-free scene-change detection whose performance is bound by metamerism and image noise, and has only one variable--the desired confidence interval for noise separation.

  8. 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.

  9. 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)

  10. Breast MRI at Very Short TE (minTE): Image Analysis of minTE Sequences on Non-Fat-Saturated, Subtracted T1-Weighted Images.

    Science.gov (United States)

    Wenkel, Evelyn; Janka, Rolf; Geppert, Christian; Kaemmerer, Nadine; Hartmann, Arndt; Uder, Michael; Hammon, Matthias; Brand, Michael

    2017-02-01

    Purpose 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. Methods 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. Results 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 Image Analysis of minTE Sequences on Non-Fat-Saturated, Subtracted T1-Weighted Images. Fortschr Röntgenstr 2017; 189: 137 - 145. © Georg Thieme Verlag KG Stuttgart · New York.

  11. MR imaging with fluid attenuated inversion recovery sequence of childhood adrenoleukodystrophy : comparison with T2 weighted spin echo imaging

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Asiry; Seo, Jeong-Jin; Jeong, Gwang Woo; Chung, Tae Woong; Jeong, Yong Yeon; Kang, Heoung Keun; Kook, Hoon; Woo, Young Jong; Hwang, Tai Joo [Chonnam Univ. Medical School, Seoul (Korea, Republic of)

    1999-03-01

    The purpose of this study was to evaluate the usefulness of FLAIR(Fluid Attenuated Inversion Recovery) MR imaging in childhood adrenoleukodystrophy by comparing with those of T2-weighted FSE imaging, and to correlate MRI findings with clinical manifestations. Axial FLAIR images(TR/TE/TI=10004/123/2200) and T2-weighted FSE images(TR/TE=4000/104) of brain in six male patients(age range : 6-17 years, mean age : 10.2 years) with biochemically confirmed adrenoleukodystrophy were compared visually by two radiologists for detection, conspicuity, and the extent of lesion. Quantitatively, we compared lesion/CSF contrast, lesion/CSF contrast to noise ratio(CNR), lesion/white matter(WM) contrast, and lesion/WM CNR between FLAIR and T2 weighted image. We correlated MR findings with clinical manifestations of neurologic symptoms and evaluated whether MRI could detect white matter lesions in neurologically asymptomatic patients. Visual detection of lesions was better with FLAIR images in 2 of the 6 cases and it was equal in the remainders. Visual conspicuity and detection of the extent of lesion were superior on FLAIR images than T2-weighted images in all 6 cases. In the quantitative assessment of lesions, FLAIR was superior to T2-weighted image for lesion/CSF contrast and lesion/CSF CNR, but was inferior to T2 weighted image for lesion/WM contrast and lesion/WM CNR. In one case, FLAIR images distinguished the portion of encephalomalacic change from lesions. MR findings of adrenoleukodystrophy were correlated with clinical manifestations in symptomatic 4 cases, and also detected white matter lesions in asymptomatic 2 cases. MR imaging with FLAIR sequence provided images that were equal or superior to T2-weighted images in the evaluation of childhood adrenoleukodystrophy. MRI findings were well correlated with clinical manifestations and could detect white matter lesions in neurologically asymptomatic adrenoleukodystrophy patients.

  12. SU-F-207-02: Use of Postmortem Subjects for Subjective Image Quality Assessment in Abdominal CT Protocols with Iterative Reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Mench, A [Salem Hospital, Salem, OR (United States); Lipnharski, I; Carranza, C; Lamoureux, R; Smajdor, L; Cormack, B; Mohammed, T; Rill, L; Arreola, M [University of Florida, Gainesville, FL (United States); Sinclair, L [Oregon Health & Science University, Portland, OR (United States)

    2015-06-15

    Purpose: New radiation dose reduction technologies are emerging constantly in the medical imaging field. The latest of these technologies, iterative reconstruction (IR) in CT, presents the ability to reduce dose significantly and hence provides great opportunity for CT protocol optimization. However, without effective analysis of image quality, the reduction in radiation exposure becomes irrelevant. This work explores the use of postmortem subjects as an image quality assessment medium for protocol optimizations in abdominal CT. Methods: Three female postmortem subjects were scanned using the Abdomen-Pelvis (AP) protocol at reduced minimum tube current and target noise index (SD) settings of 12.5, 17.5, 20.0, and 25.0. Images were reconstructed using two strengths of iterative reconstruction. Radiologists and radiology residents from several subspecialties were asked to evaluate 8 AP image sets including the current facility default scan protocol and 7 scans with the parameters varied as listed above. Images were viewed in the soft tissue window and scored on a 3-point scale as acceptable, borderline acceptable, and unacceptable for diagnosis. The facility default AP scan was identified to the reviewer while the 7 remaining AP scans were randomized and de-identified of acquisition and reconstruction details. The observers were also asked to comment on the subjective image quality criteria they used for scoring images. This included visibility of specific anatomical structures and tissue textures. Results: Radiologists scored images as acceptable or borderline acceptable for target noise index settings of up to 20. Due to the postmortem subjects’ close representation of living human anatomy, readers were able to evaluate images as they would those of actual patients. Conclusion: Postmortem subjects have already been proven useful for direct CT organ dose measurements. This work illustrates the validity of their use for the crucial evaluation of image quality

  13. Approach for moving small target detection in infrared image sequence based on reinforcement learning

    Science.gov (United States)

    Wang, Chuanyun; Qin, Shiyin

    2016-09-01

    Addressing the problems of moving small target detection in infrared image sequence caused by background clutter and target size variation with time, an approach for moving small target detection is proposed under a pipeline framework with an optimization strategy based on reinforcement learning. The pipeline framework is composed by pipeline establishment, target-background images separation, and target confirmation, in which the pipeline is established by designating several successive images with temporal sliding window, target-background images separation is dealt with low-rank and sparse matrix decomposition via robust principal component analysis, and target confirmation is achieved by employing a voting mechanism over more than one separated target images of the same input image. For unremitting optimization of target-background images separation, the weighting parameter of low-rank and sparse matrix decomposition is dynamically regulated by the way of reinforcement learning in consecutive detection, in which the complexity evaluation from sequential infrared images and results assessment of moving small target detection are integrated. The experiment results over four infrared small target image sequences with different cloudy sky backgrounds demonstrate the effectiveness and advantages of the proposed approach in both background clutter suppression and small target detection.

  14. Iteration and superposition encryption scheme for image sequences based on multi-dimensional keys

    Science.gov (United States)

    Han, Chao; Shen, Yuzhen; Ma, Wenlin

    2017-12-01

    An iteration and superposition encryption scheme for image sequences based on multi-dimensional keys is proposed for high security, big capacity and low noise information transmission. Multiple images to be encrypted are transformed into phase-only images with the iterative algorithm and then are encrypted by different random phase, respectively. The encrypted phase-only images are performed by inverse Fourier transform, respectively, thus new object functions are generated. The new functions are located in different blocks and padded zero for a sparse distribution, then they propagate to a specific region at different distances by angular spectrum diffraction, respectively and are superposed in order to form a single image. The single image is multiplied with a random phase in the frequency domain and then the phase part of the frequency spectrums is truncated and the amplitude information is reserved. The random phase, propagation distances, truncated phase information in frequency domain are employed as multiple dimensional keys. The iteration processing and sparse distribution greatly reduce the crosstalk among the multiple encryption images. The superposition of image sequences greatly improves the capacity of encrypted information. Several numerical experiments based on a designed optical system demonstrate that the proposed scheme can enhance encrypted information capacity and make image transmission at a highly desired security level.

  15. Cryptanalysis of an Image Encryption Algorithm Based on DNA Sequence Operation and Hyper-chaotic System

    Science.gov (United States)

    Xu, Ming

    2017-06-01

    Recently, chaotic image cipher using DNA sequence operation has been studied extensively. However, corresponding cryptanalysis is lacking, which impedes its further development. This paper cryptanalyzes a newly proposed chaotic image cipher based on DNA sequence operation. In this paper, we firstly analyze the security defects of the proposal. Then by applying chosen-plaintext attack, we show that all the secret parameters can be revealed. The effectiveness of the proposed chosen-plaintext attack is supported both by rigorous theoretical analysis and experimental results.

  16. Ultrasonic Shear Wave Elasticity Imaging (SWEI) Sequencing and Data Processing Using a Verasonics Research Scanner.

    Science.gov (United States)

    Deng, Yufeng; Rouze, Ned C; Palmeri, Mark L; Nightingale, Kathryn R

    2016-10-03

    Ultrasound elasticity imaging has been developed over the last decade to estimate tissue stiffness. Shear wave elasticity imaging (SWEI) quantifies tissue stiffness by measuring the speed of propagating shear waves following acoustic radiation force excitation. This work presents the sequencing and data processing protocols of SWEI using a Verasonics system. The selection of the sequence parameters in a Verasonics programming script is discussed in detail. The data processing pipeline to calculate group shear wave speed (SWS), including tissue motion estimation, data filtering, and SWS estimation is demonstrated. In addition, the procedures for calibration of beam position, scanner timing, and transducer face heating are provided to avoid SWS measurement bias and transducer damage.

  17. Ultrasonic Shear Wave Elasticity Imaging Sequencing and Data Processing Using a Verasonics Research Scanner.

    Science.gov (United States)

    Deng, Yufeng; Rouze, Ned C; Palmeri, Mark L; Nightingale, Kathryn R

    2017-01-01

    Ultrasound elasticity imaging has been developed over the last decade to estimate tissue stiffness. Shear wave elasticity imaging (SWEI) quantifies tissue stiffness by measuring the speed of propagating shear waves following acoustic radiation force excitation. This paper presents the sequencing and data processing protocols of SWEI using a Verasonics system. The selection of the sequence parameters in a Verasonics programming script is discussed in detail. The data processing pipeline to calculate group shear wave speed (SWS), including tissue motion estimation, data filtering, and SWS estimation, is demonstrated. In addition, the procedures for calibration of beam position, scanner timing, and transducer face heating are provided to avoid SWS measurement bias and transducer damage.

  18. 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.

  19. 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.

  20. 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.

  1. Network, anatomical, and non-imaging measures for the prediction of ADHD diagnosis in individual subjects

    Directory of Open Access Journals (Sweden)

    Jason W Bohland

    2012-12-01

    Full Text Available Brain imaging methods have long held promise as diagnostic aids for neuropsychiatric conditions with complex behavioral phenotypes such as Attention-Deficit/Hyperactivity Disorder. This promise has largely been unrealized, at least partly due to the heterogeneity of clinical populations and the small sample size of many studies. A large, multi-center dataset provided by the ADHD-200 Consortium affords new opportunities to test methods for individual diagnosis based on MRI-observable structural brain attributes and functional interactions observable from resting state fMRI. In this study, we systematically calculated a large set of standard and new quantitative markers from individual subject datasets. These features (>12,000 per subject consisted of local anatomical attributes such as cortical thickness and structure volumes and both local and global resting state network measures. Three methods were used to compute graphs representing interdependencies between activations in different brain areas, and a full set of network features was derived from each. Of these, features derived from the inverse of the time series covariance matrix, under an L1-norm regularization penalty, proved most powerful. Anatomical and network feature sets were used individually, and combined with non-imaging phenotypic features from each subject. Machine learning algorithms were used to rank attributes, and performance was assessed under cross-validation and on a separate test set of 168 subjects for a variety of feature set combinations. While non-imaging features gave highest performance in cross-validation, the addition of imaging features in sufficient numbers led to improved generalization to new data. Stratification by gender also proved to be a fruitful strategy to improve classifier performance. We describe the overall approach used, compare the predictive power of different classes of features, and describe the most impactful features in relation to the

  2. The comparison of subjective image quality in conventional and digital panoramic radiography

    OpenAIRE

    Peker Ilkay; Toraman Alkurt; Usalan G; Altunkaynak B

    2009-01-01

    Objective: The purpose of this study was to compare the subjective image quality of (1) regular intensifying screens with medium intensifying screens, (2) regular intensifying screens with digital radiography, and (3) medium intensifying screens with digital radiography for panoramic radiographs. Materials and Methods: Forty-five patients participated and a total of 90 radiographs were obtained in the study. The patients were divided into three groups (regular-medium intensifying screen, r...

  3. Image driven subject-specific finite element models of spinal biomechanics.

    Science.gov (United States)

    Zanjani-Pour, Sahand; Winlove, C Peter; Smith, Christopher W; Meakin, Judith R

    2016-04-11

    Finite element (FE) modelling is an established technique for investigating spinal biomechanics. Using image data to produce FE models with subject-specific geometry and displacement boundary conditions may help extend their use to the assessment spinal loading in individuals. Lumbar spine magnetic resonance images from nine participants in the supine, standing and sitting postures were obtained and 2D poroelastic FE models of the lumbar spine were created from the supine data. The rigid body translation and rotation of the vertebral bodies as the participant moved to standing or sitting were applied to the model. The resulting pore pressure in the centre of the L4/L5 disc was determined and the sensitivity to the material properties and vertebral body displacements was assessed. Although the limitations of using a 2D model mean the predicted pore pressures are unlikely to be accurate, the results showed that subject-specific variation in geometry and motion during postural change leads to variation in pore pressure. The model was sensitive to the Young׳s modulus of the annulus matrix, the permeability of the nucleus, and the vertical translation of the vertebrae. This study demonstrates the feasibility of using image data to drive subject-specific lumbar spine FE models and indicates where further development is required to provide a method for assessing spinal biomechanics in a wide range of individuals. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Subjective quality and depth assessment in stereoscopic viewing of volume-rendered medical images

    Science.gov (United States)

    Rousson, Johanna; Couturou, Jeanne; Vetsuypens, Arnout; Platisa, Ljiljana; Kumcu, Asli; Kimpe, Tom; Philips, Wilfried

    2014-03-01

    No study to-date explored the relationship between perceived image quality (IQ) and perceived depth (DP) in stereoscopic medical images. However, this is crucial to design objective quality metrics suitable for stereoscopic medical images. This study examined this relationship using volume-rendered stereoscopic medical images for both dual- and single-view distortions. The reference image was modified to simulate common alterations occurring during the image acquisition stage or at the display side: added white Gaussian noise, Gaussian filtering, changes in luminance, brightness and contrast. We followed a double stimulus five-point quality scale methodology to conduct subjective tests with eight non-expert human observers. The results suggested that DP was very robust to luminance, contrast and brightness alterations and insensitive to noise distortions until standard deviation σ=20 and crosstalk rates of 7%. In contrast, IQ seemed sensitive to all distortions. Finally, for both DP and IQ, the Friedman test indicated that the quality scores for dual-view distortions were significantly worse than scores for single-view distortions for multiple blur levels and crosstalk impairments. No differences were found for most levels of brightness, contrast and noise distortions. So, DP and IQ didn't react equivalently to identical impairments, and both depended whether dual- or single-view distortions were applied.

  5. Estimation of temporal evolution of the helium plasmasphere based on a sequence of IMAGE/EUV images

    Science.gov (United States)

    Nakano, S.; Fok, M.-C.; Brandt, P. C.; Higuchi, T.

    2014-05-01

    We have developed a technique for estimating the temporal evolution of the plasmaspheric helium ion density based on a sequence of extreme ultraviolet (EUV) data obtained from the IMAGE satellite. In the proposed technique, the estimation is obtained by incorporating EUV images from IMAGE into a two-dimensional fluid model of the plasmasphere using a data assimilation approach based on the ensemble transform Kalman filter. Since the motion and the spatial structure of the helium plasmasphere is strongly controlled by the electric field in the inner magnetosphere, the electric field around the plasmapause can also be estimated using the ensemble transform Kalman filter. We performed an experiment using synthetic images that were generated from the same numerical model under a certain condition. It was confirmed that the condition that generated the synthetic images was successfully reproduced. We also present some results obtained using real EUV imaging data. Finally, we discuss the possibility of estimating the density profile along a magnetic field line. Since each EUV image was taken from a different direction due to the motion of the IMAGE satellite, we could obtain the information on the density profile along a field line by combining multiple images.

  6. 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.

  7. On the effect of subliminal priming on subjective perception of images: a machine learning approach.

    Science.gov (United States)

    Kumar, Parmod; Mahmood, Faisal; Mohan, Dhanya Menoth; Wong, Ken; Agrawal, Abhishek; Elgendi, Mohamed; Shukla, Rohit; Dauwels, Justin; Chan, Alice H D

    2014-01-01

    The research presented in this article investigates the influence of subliminal prime words on peoples' judgment about images, through electroencephalograms (EEGs). In this cross domain priming paradigm, the participants are asked to rate how much they like the stimulus images, on a 7-point Likert scale, after being subliminally exposed to masked lexical prime words, with EEG recorded simultaneously. Statistical analysis tools are used to analyze the effect of priming on behavior, and machine learning techniques to infer the primes from EEGs. The experiment reveals strong effects of subliminal priming on the participants' explicit rating of images. The subjective judgment affected by the priming makes visible change in event-related potentials (ERPs); results show larger ERP amplitude for the negative primes compared with positive and neutral primes. In addition, Support Vector Machine (SVM) based classifiers are proposed to infer the prime types from the average ERPs, which yields a classification rate of 70%.

  8. 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)

  9. Analysis of 16S rRNA gene sequences and circulating cell-free DNA from plasma of chronic fatigue syndrome and non-fatigued subjects

    Directory of Open Access Journals (Sweden)

    Unger Elizabeth R

    2002-12-01

    Full Text Available Abstract Background The association of an infectious agent with chronic fatigue syndrome (CFS has been difficult and is further complicated by the lack of a known lesion or diseased tissue. Cell-free plasma DNA could serve as a sentinel of infection and disease occurring throughout the body. This type of systemic sample coupled with broad-range amplification of bacterial sequences was used to determine whether a bacterial pathogen was associated with CFS. Plasma DNA from 34 CFS and 55 non-fatigued subjects was assessed to determine plasma DNA concentration and the presence of bacterial 16S ribosomal DNA (rDNA sequences. Results DNA was isolated from 81 (91% of 89 plasma samples. The 55 non-fatigued subjects had higher plasma DNA concentrations than those with CFS (average 151 versus 91 ng and more CFS subjects (6/34, 18% had no detectable plasma DNA than non-fatigued subjects (2/55, 4%, but these differences were not significant. Bacterial sequences were detected in 23 (26% of 89. Only 4 (14% CFS subjects had 16S rDNA sequences amplified from plasma compared with 17 (32% of the non-fatigued (P = 0.03. All but 1 of the 23 16S rDNA amplicon-positive subjects had five or more unique sequences present. Conclusions CFS subjects had slightly lower concentrations or no detectable plasma DNA than non-fatigued subjects. There was a diverse array of 16S rDNA sequences in plasma DNA from both CFS and non-fatigued subjects. There were no unique, previously uncharacterized or predominant 16S rDNA sequences in either CFS or non-fatigued subjects.

  10. Spatially Varying Image Based Lighting by Light Probe Sequences, Capture, Processing and Rendering

    OpenAIRE

    Unger, Jonas; Gustavson, Stefan; Ynnerman, Anders

    2007-01-01

    We present a novel technique for capturing spatially or temporally resolved light probe sequences, and using them for image based lighting. For this purpose we have designed and built a real-time light probe, a catadioptric imaging system that can capture the full dynamic range of the lighting incident at each point in space at video frame rates, while being moved through a scene. The real-time light probe uses a digital imaging system which we have programmed to capture high quality, photome...

  11. Image-model coupling: a simple information theoretic perspective for image sequences

    Directory of Open Access Journals (Sweden)

    N. D. Smith

    2009-03-01

    Full Text Available Images are widely used to visualise physical processes. Models may be developed which attempt to replicate those processes and their effects. The technique of coupling model output to images, which is here called "image-model coupling", may be used to help understand the underlying physical processes, and better understand the limitations of the models. An information theoretic framework is presented for image-model coupling in the context of communication along a discrete channel. The physical process may be regarded as a transmitter of images and the model as part of a receiver which decodes or recognises those images. Image-model coupling may therefore be interpreted as image recognition. Of interest are physical processes which exhibit "memory". The response of such a system is not only dependent on the current values of driver variables, but also on the recent history of drivers and/or system description. Examples of such systems in geophysics include the ionosphere and Earth's climate. The discrete channel model is used to help derive expressions for matching images and model output, and help analyse the coupling.

  12. Image-model coupling: a simple information theoretic perspective for image sequences

    Science.gov (United States)

    Smith, N. D.; Mitchell, C. N.; Budd, C. J.

    2009-03-01

    Images are widely used to visualise physical processes. Models may be developed which attempt to replicate those processes and their effects. The technique of coupling model output to images, which is here called "image-model coupling", may be used to help understand the underlying physical processes, and better understand the limitations of the models. An information theoretic framework is presented for image-model coupling in the context of communication along a discrete channel. The physical process may be regarded as a transmitter of images and the model as part of a receiver which decodes or recognises those images. Image-model coupling may therefore be interpreted as image recognition. Of interest are physical processes which exhibit "memory". The response of such a system is not only dependent on the current values of driver variables, but also on the recent history of drivers and/or system description. Examples of such systems in geophysics include the ionosphere and Earth's climate. The discrete channel model is used to help derive expressions for matching images and model output, and help analyse the coupling.

  13. Live cell imaging of repetitive DNA sequences via GFP-tagged polydactyl zinc finger proteins

    Science.gov (United States)

    Lindhout, Beatrice I.; Fransz, Paul; Tessadori, Federico; Meckel, Tobias; Hooykaas, Paul J.J.; van der Zaal, Bert J.

    2007-01-01

    Several techniques are available to study chromosomes or chromosomal domains in nuclei of chemically fixed or living cells. Current methods to detect DNA sequences in vivo are limited to trans interactions between a DNA sequence and a transcription factor from natural systems. Here, we expand live cell imaging tools using a novel approach based on zinc finger-DNA recognition codes. We constructed several polydactyl zinc finger (PZF) DNA-binding domains aimed to recognize specific DNA sequences in Arabidopsis and mouse and fused these with GFP. Plants and mouse cells expressing PZF:GFP proteins were subsequently analyzed by confocal microscopy. For Arabidopsis, we designed a PZF:GFP protein aimed to specifically recognize a 9-bp sequence within centromeric 180-bp repeat and monitored centromeres in living roots. Similarly, in mouse cells a PZF:GFP protein was targeted to a 9-bp sequence in the major satellite repeat. Both PZF:GFP proteins localized in chromocenters which represent heterochromatin domains containing centromere and other tandem repeats. The number of PZF:GFP molecules per centromere in Arabidopsis, quantified with near single-molecule precision, approximated the number of expected binding sites. Our data demonstrate that live cell imaging of specific DNA sequences can be achieved with artificial zinc finger proteins in different organisms. PMID:17704126

  14. 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.

  15. Single-heartbeat electromechanical wave imaging with optimal strain estimation using temporally unequispaced acquisition sequences.

    Science.gov (United States)

    Provost, Jean; Thiébaut, Stéphane; Luo, Jianwen; Konofagou, Elisa E

    2012-02-21

    Electromechanical Wave Imaging (EWI) is a non-invasive, ultrasound-based imaging method capable of mapping the electromechanical wave (EW) in vivo, i.e. the transient deformations occurring in response to the electrical activation of the heart. Optimal imaging frame rates, in terms of the elastographic signal-to-noise ratio, to capture the EW cannot be achieved due to the limitations of conventional imaging sequences, in which the frame rate is low and tied to the imaging parameters. To achieve higher frame rates, EWI is typically performed by combining sectors acquired during separate heartbeats, which are then combined into a single view. However, the frame rates achieved remain potentially sub-optimal and this approach precludes the study of non-periodic arrhythmias. This paper describes a temporally unequispaced acquisition sequence (TUAS) for which a wide range of frame rates are achievable independently of the imaging parameters, while maintaining a full view of the heart at high beam density. TUAS is first used to determine the optimal frame rate for EWI in a paced canine heart in vivo and then to image during ventricular fibrillation. These results indicate how EWI can be optimally performed within a single heartbeat, during free breathing and in real time, for both periodic and non-periodic cardiac events.

  16. Accuracy of ultrasound imaging technique for assessing lipoatrophy in HIV-infected subjects.

    Science.gov (United States)

    Ferraioli, Giovanna; Tinelli, Carmine; Scudeller, Luigia; Filice, Gaetano; Filice, Carlo

    2011-07-01

    To compare the accuracy of ultrasound imaging technique to that of clinical diagnosis in evaluating subcutaneous fat changes in HIV-infected subjects. HIV-uninfected control subjects (Group A), HIV-infected subjects with clinically assessed lipoatrophy (Group B), and HIV-infected subjects without clinical lipoatrophy (Group C) underwent ultrasound measurements of subcutaneous fat thickness at facial, brachial and thigh regions. ROC curve analyses were used to estimate ultrasound prediction accuracy and cut-off values of subcutaneous fat thickness. 228 subjects were enrolled: 78 in Group A, 73 in Group B, and 77 in Group C. Facial lipoatrophy: ROC curve analysis identified optimal cut-off value of 13.3 mm [sensitivity, 96.0%; specificity, 76.9% AUC 0.92], 5.0 mm [sensitivity, 71.4%; specificity, 92.3%; AUC 0.90] and 11.2 mm [sensitivity, 95.8%; specificity, 89.7%; AUC 0.97] for females and 12.05 mm [sensitivity, 51.2%; specificity, 87.2%; AUC 0.74], 4.1 mm [sensitivity, 76.2%; specificity, 89.7%; AUC 0.85] and 4.35 mm [sensitivity, 60.0%; specificity, 89.7%; AUC 0.82] for males in assessing facial, brachial and crural lipoatrophy respectively. Using this cut-off values, 12/25 (48%) females and 17/49 (34.7%) males, 12/28 (42.9%) females and 23/49 (46.9%) males, 19/28 (67.9%) females and 12/49 (24.5%) males in Group C would be classified as "sub-clinical" facial, brachial and crural lipoatrophy respectively. The results of our study show that in the assessment of subtle subcutaneous fat changes ultrasound is more accurate than clinical evaluation and confirm the usefulness of ultrasound imaging technique in identifying lipoatrophy at an early stage.

  17. SCALE-PWI: A pulse sequence for absolute quantitative cerebral perfusion imaging.

    Science.gov (United States)

    Srour, Jessy Mouannes; Shin, Wanyong; Shah, Saurabh; Sen, Anindya; Carroll, Timothy J

    2011-05-01

    The Bookend technique is a magnetic resonance imaging (MRI) dynamic susceptibility contrast method that provides reliable quantitative measurement of cerebral blood flow (CBF) and cerebral blood volume (CBV). The quantification is patient specific, is derived from a steady-state measurement of CBV, and is obtained from T(1) changes in the white matter and the blood pool after contrast agent injection. In the current implementation, the Bookend technique consists of three scanning steps requiring a cumulative scan time of 3 minutes 47 seconds, a well-trained technologist, and extra time for offline image reconstruction. We present an automation and acceleration of the multiscan Bookend protocol through a self-calibrating pulse sequence, namely Self-Calibrated Epi Perfusion-Weighted Imaging (SCALE-PWI). The SCALE-PWI is a single-shot echo-planar imaging pulse sequence with three modules and a total scan time of under 2 minutes. It provides the possibility of performing online, quantitative perfusion image reconstruction, which reduces the latency to obtain quantitative maps. A validation study in healthy volunteers (N=19) showed excellent agreement between SCALE-PWI and the conventional Bookend protocol (P>0.05 with Student's t-test, r=0.95/slope=0.98 for quantitative CBF, and r=0.91/slope=0.94 for quantitative CBV). A single MRI pulse sequence for absolute quantification of cerebral perfusion has been developed.

  18. 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

  19. [Subjective family image in anorexia nervosa and bulimia nervosa in adolescence: a controlled study].

    Science.gov (United States)

    Karwautz, A; Haidvogl, M; Wagner, G; Nobis, G; Wöber-Bingöl, C; Friedrich, M H

    2002-11-01

    The family environments of patients with eating disorders have been studied extensively in recent decades. The "Subjective Family Image Test" is an instrument developed especially to measure differential perceptions by family members. Assessments of subjective family image in families of adolescents by means of this test have been carried out in only a few samples. We aimed first to investigate subjective perceptions by adolescents of their family relations in a larger clinical sample of female adolescents (n = 118) suffering from anorexia nervosa of either subtype or from bulimia nervosa and to compare these perceptions with those of healthy controls (n = 96). Second we investigated intra-familial differences in perception. The main findings were that bulimia nervosa patients perceived lower individual autonomy and lower emotional connectedness than all other groups, the adolescents with bulimia perceived significantly lower autonomy and emotional connectedness within the family than their fathers, and the restrictive anorexia nervosa patients perceived higher connectedness than their fathers. The relevance of these findings for understanding family dynamics are discussed.

  20. Seven neurons memorizing sequences of alphabetical images via spike-timing dependent plasticity.

    Science.gov (United States)

    Osogami, Takayuki; Otsuka, Makoto

    2015-09-16

    An artificial neural network, such as a Boltzmann machine, can be trained with the Hebb rule so that it stores static patterns and retrieves a particular pattern when an associated cue is presented to it. Such a network, however, cannot effectively deal with dynamic patterns in the manner of living creatures. Here, we design a dynamic Boltzmann machine (DyBM) and a learning rule that has some of the properties of spike-timing dependent plasticity (STDP), which has been postulated for biological neural networks. We train a DyBM consisting of only seven neurons in a way that it memorizes the sequence of the bitmap patterns in an alphabetical image "SCIENCE" and its reverse sequence and retrieves either sequence when a partial sequence is presented as a cue. The DyBM is to STDP as the Boltzmann machine is to the Hebb rule.

  1. Magnetic resonance imaging of the Achilles tendon using ultrashort TE (UTE) pulse sequences

    Energy Technology Data Exchange (ETDEWEB)

    Robson, M.D.; Benjamin, M.; Gishen, P.; Bydder, G.M. E-mail: gbydder@ucsd.edu

    2004-08-01

    AIM: To assess the potential value of imaging the Achilles tendon with ultrashort echo time (UTE) pulse sequences. MATERIALS AND METHODS: Four normal controls and four patients with chronic Achilles tendinopathy were examined in the sagittal and transverse planes. Three of the patients were examined before and after intravenous gadodiamide. RESULTS: The fascicular pattern was clearly demonstrated within the tendon and detail of the three distinct fibrocartilaginous components of an 'enthesis organ' was well seen. T2* measurements showed two short T2* components. Increase in long T2 components with reduction in short T2 components was seen in tendinopathy. Contrast enhancement was much more extensive than with conventional sequences in two cases of tendinopathy but in a third case, there was a region of reduced enhancement. CONCLUSION: UTE pulse sequences provide anatomical detail not apparent with conventional sequences, demonstrate differences in T2* and show patterns of both increased and decreased enhancement in tendinopathy.

  2. Rapid Targeted Next-Generation Sequencing Platform for Molecular Screening and Clinical Genotyping in Subjects with Hemoglobinopathies

    Directory of Open Access Journals (Sweden)

    Xuan Shang

    2017-09-01

    Full Text Available Hemoglobinopathies are among the most common autosomal-recessive disorders worldwide. A comprehensive next-generation sequencing (NGS test would greatly facilitate screening and diagnosis of these disorders. An NGS panel targeting the coding regions of hemoglobin genes and four modifier genes was designed. We validated the assay by using 2522 subjects affected with hemoglobinopathies and applied it to carrier testing in a cohort of 10,111 couples who were also screened through traditional methods. In the clinical genotyping analysis of 1182 β-thalassemia subjects, we identified a group of additional variants that can be used for accurate diagnosis. In the molecular screening analysis of the 10,111 couples, we detected 4180 individuals in total who carried 4840 mutant alleles, and identified 186 couples at risk of having affected offspring. 12.1% of the pathogenic or likely pathogenic variants identified by our NGS assay, which were undetectable by traditional methods. Compared with the traditional methods, our assay identified an additional at-risk 35 couples. We describe a comprehensive NGS-based test that offers advantages over the traditional screening/molecular testing methods. To our knowledge, this is among the first large-scale population study to systematically evaluate the application of an NGS technique in carrier screening and molecular diagnosis of hemoglobinopathies.

  3. Multicenter study of subjective acceptance during magnetic resonance imaging at 7 and 9.4 T.

    Science.gov (United States)

    Rauschenberg, Jaane; Nagel, Armin M; Ladd, Susanne C; Theysohn, Jens M; Ladd, Mark E; Möller, Harald E; Trampel, Robert; Turner, Robert; Pohmann, Rolf; Scheffler, Klaus; Brechmann, André; Stadler, Jörg; Felder, Jörg; Shah, N Jon; Semmler, Wolfhard

    2014-05-01

    The aims of this study were to investigate the subjective discomfort and sensory side effects during ultrahigh field (UHF) magnetic resonance imaging (MRI) examinations in a large-scale study and to evaluate differences between magnetic resonance (MR) sites. Four MR sites with a 7-T MR system and 2 MR sites with a 9.4-T MR system participated in this multicenter study with a total number of 3457 completed questionnaires on causes of discomfort and sensations during the examination. For a pooled retrospective analysis of the results from the partially different questionnaires, all data were adapted to an answer option with a 4-point scale (0 = no discomfort/side effect, 3 = very unpleasant/very strong sensation). To differentiate effects evoked by the low-frequency time-varying magnetic fields due to movement through the static magnetic field, most questionnaires separated the manifestation of sensory side effects during movement on the patient table from manifestation while lying still in the isocenter. In general, a high acceptance of UHF examinations was found, where in 82% of the completed questionnaires, the subjects stated the examination to be at least tolerable. Although in 7.6% of the questionnaires, subjects felt discomfort during the examination, only 0.9% of the image acquisitions had to be terminated prematurely. No adverse events occurred in any of the examinations. Only 1% of the subjects were unwilling to undergo further UHF MRI examinations. Examination duration was the most complained cause of discomfort, followed by acoustic noise and lying still. All magnetic-field-related sensations were more pronounced when moving the patient table versus the isocenter position (19%/2% of the subjects felt unpleasant vertigo during the moving/stationary state). In general, vertigo was the most often stated sensory side effect and was more pronounced at 9.4 T compared with 7 T. However, the results varied substantially among the different sites. The high levels

  4. Myocardial T1: quantification by using an ECG-triggered radial single-shot inversion-recovery MR imaging sequence.

    Science.gov (United States)

    Gensler, Daniel; Mörchel, Philipp; Fidler, Florian; Ritter, Oliver; Quick, Harald H; Ladd, Mark E; Bauer, Wolfgang R; Ertl, Georg; Jakob, Peter M; Nordbeck, Peter

    2015-03-01

    To develop and validate a fast cardiac magnetic resonance imaging T1 mapping technique with high spatial resolution based on a radial inversion-recovery (IR) spoiled gradient-echo acquisition. Approval for the study was granted by the local institutional review board, and all subjects gave written informed consent. An electrocardiographically triggered radial single-shot IR (TRASSI) sequence was developed in conjunction with a custom-written fitting algorithm. The proposed imaging technique was validated in phantom measurements and then used for cardiac T1 mapping in 62 subjects with or without cardiac disease. The study population included 51 healthy subjects, three patients with arrhythmia, and eight patients with myocardial infarction. The potential heart rate dependency of the TRASSI method was tested by using linear regression analysis. Statistically significant differences between the sexes and various section orientations were analyzed with a Student t test for independent groups and a repeated-measures analysis of variance for dependent groups. High-spatial-resolution T1 maps (1.17 × 1.17 mm) without motion artifacts and without heart rate dependency (slope = -0.0303, R(2) = 0.0000887, P = .899) were acquired with an acquisition time of less than 6 seconds in all subjects. The mean T1 of healthy left ventricular myocardium across all examined subjects was 1031 msec ± 33 (standard deviation). Testing for reproducibility in three individuals with 34 repetitive measurements revealed a mean standard deviation of 4.1 msec (0.412%). Subacute and chronic myocardial infarction could be detected in all eight patients. T1 disturbances due to arrhythmia proved to be minimal in three patients (standard deviation, T1 mapping is feasible within a single-shot IR experiment.

  5. [Sexuality and the human body: the subject's view through video images].

    Science.gov (United States)

    Vargas, E; Siqueira, V H

    1999-11-01

    This study analyzes images of the body linked to sexual and reproductive behavior found in the communication processes mediated by so-called educational videos. In the relationship between subject and technology, the paper is intended to characterize the discourses and the view or perspective currently shaping health education practices. Focusing on the potential in the relationship between the enunciator and subjects represented in the text and the interaction between health professionals and messages, the study attempts to characterize the discourses and questions providing the basis for a given view of the body and sexuality. The study was conducted in the years 1996-1997 and focused on health professionals from the public health system. The results show a concept of sexuality that tends to generalize the meaning ascribed to sexual experience, ignoring the various ways by which different culturally defined groups attribute meaning to the body.

  6. Hierarchical Matching of Uncertain Building Models with Oblique View Airborne IR Image Sequences

    Science.gov (United States)

    Iwaszczuk, D.; Hoegner, L.; Schmitt, M.; Stilla, U.

    2012-07-01

    Thermal building textures can be used for detection of damaged and weak spots in the building structure. These textures can be extracted from airborne infrared (IR) image sequences by projecting the 3D building model into the images. However, the direct georeferencing is often not sufficiently accurate and the projected 3D model does not match the structures in the image. Thus we present a technique with the main goal to find the best fit between the existing 3D building model and the IR image sequence. For this purpose we developed a hierarchical approach consisting of two working stages. In the first stage we correct exterior orientation via line based matching. In the adjustment we consider both uncertainties: the ones of the model and the ones of the image. In the second stage we match each edge separately in its closest surrounding. Thanks to this approach a better fit between the 3D building model and the IR image was found. The originally unmodeled roof overlap was reconstructed.

  7. Current density imaging sequence for monitoring current distribution during delivery of electric pulses in irreversible electroporation.

    Science.gov (United States)

    Serša, Igor; Kranjc, Matej; Miklavčič, Damijan

    2015-01-01

    Electroporation is gaining its importance in everyday clinical practice of cancer treatment. For its success it is extremely important that coverage of the target tissue, i.e. treated tumor, with electric field is within the specified range. Therefore, an efficient tool for the electric field monitoring in the tumor during delivery of electroporation pulses is needed. The electric field can be reconstructed by the magnetic resonance electric impedance tomography method from current density distribution data. In this study, the use of current density imaging with MRI for monitoring current density distribution during delivery of irreversible electroporation pulses was demonstrated. Using a modified single-shot RARE sequence, where four 3000 V and 100 μs long pulses were included at the start, current distribution between a pair of electrodes inserted in a liver tissue sample was imaged. Two repetitions of the sequence with phases of refocusing radiofrequency pulses 90° apart were needed to acquire one current density image. For each sample in total 45 current density images were acquired to follow a standard protocol for irreversible electroporation where 90 electric pulses are delivered at 1 Hz. Acquired current density images showed that the current density in the middle of the sample increased from first to last electric pulses by 60%, i.e. from 8 kA/m2 to 13 kA/m2 and that direction of the current path did not change with repeated electric pulses significantly. The presented single-shot RARE-based current density imaging sequence was used successfully to image current distribution during delivery of short high-voltage electric pulses. The method has a potential to enable monitoring of tumor coverage by electric field during irreversible electroporation tissue ablation.

  8. Bilateral transfer phenomenon: A functional magnetic resonance imaging pilot study of healthy subjects.

    Science.gov (United States)

    Uggetti, Carla; Ausenda, Carlo D; Squarza, Silvia; Cadioli, Marcello; Grimoldi, Ludovico; Cerri, Cesare; Cariati, Maurizio

    2016-08-01

    The bilateral transfer of a motor skill is a physiological phenomenon: the development of a motor skill with one hand can trigger the development of the same ability of the other hand. The purpose of this study was to verify whether bilateral transfer is associated with a specific brain activation pattern using functional magnetic resonance imaging (fMRI). The motor task was implemented as the execution of the Nine Hole Peg Test. Fifteen healthy subjects (10 right-handers and five left-handers) underwent two identical fMRI runs performing the motor task with the non-dominant hand. Between the first and the second run, each subject was intensively trained for five minutes to perform the same motor task with the dominant hand. Comparing the two functional scans across the pool of subjects, a change of the motor activation pattern was observed. In particular, we observed, in the second run, a change in the activation pattern both in the cerebellum and in the cerebral cortex. We found activations in cortical areas involved in somatosensory integration, areas involved in procedural memory. Our study shows, in a small group of healthy subjects, the modification of the fMRI activation pathway of a motor task performed by the non-dominant hand after intensive exercise performing the same task with the dominant hand. © The Author(s) 2016.

  9. Magnetic resonance imaging of cerebral anomalies in subjects with resistance to thyroid hormone

    Energy Technology Data Exchange (ETDEWEB)

    Leonard, C.M. [Univ. of Florida Health Science Center, Gainesville, FL (United States); Hauser, P.; Weintraub, B.D. [National Institute of Mental Health, Bethesda, MD (United States)]|[Baltimore VA Medical Center, MD (United States)] [and others

    1995-06-19

    Resistance to thyroid hormone (RTH) is an autosomal dominant disease caused by mutations in the human thyroid receptor beta gene on chromosome 3. Individuals with RTH have an increased incidence of attention deficit hyperactivity disorder (ADHD). The purpose of this study was to search for developmental brain malformations associated with RTH. Forty-three subjects (20 affected males [AM], 23 affected females [AF]) with resistance to thyroid hormone and 32 unaffected first degree relatives (18 unaffected males [UM], 14 unaffected females [UF]) underwent MRI brain scans with a volumetric acquisition that provided 90 contiguous 2 mm thick sagittal images. Films of six contiguous images beginning at a standard sagittal position lateral to the insula were analyzed by an investigator who was blind with respect to subject characteristics. The presence of extra or missing gyri in the parietal bank of the Sylvian fissure (multimodal association cortex) and multiple Heschl`s transverse gyri (primary auditory cortex) were noted. There was a significantly increased frequency of anomalous Sylvian fissures in the left hemisphere in males with RTH (AM: 70%; AF: 30%; UM: 28% UF: 28%). Also, there was an increased frequency of anomalous Sylvian fissures on the left combined with multiple Heschl`s gyri in either hemisphere in males with RTH (AM: 50%; AF: 9%; UM: 6%; UF: 0%). However, RTH subjects with anomalies did not have an increased frequency of ADHD as compared with RTH subjects with no anomalies. Abnormal thyroid hormone action in the male fetus early during brain development may be associated with grossly observable cerebral anomalies of the left hemisphere. The effects of mutations in the thyroid receptor beta gene provide a model system for studying the complex interaction of genetic and non-genetic factors on brain and behavioral development. 19 refs., 2 figs., 2 tabs.

  10. A rapid Look-Locker imaging sequence for quantitative tissue oximetry

    Science.gov (United States)

    Vidya Shankar, Rohini; Kodibagkar, Vikram D.

    2015-03-01

    Tissue oximetry studies using magnetic resonance imaging are increasingly contributing to advances in the imaging and treatment of cancer. The non-invasive measurement of tissue oxygenation (pO2) may facilitate a better understanding of the pathophysiology and prognosis of diseases, particularly in the assessment of the extensive hypoxic regions associated with cancerous lesions. The availability of tumor hypoxia maps could help quantify and predict tumor response to intervention and therapy. The PISTOL (Proton Imaging of Siloxanes to map Tissue Oxygenation Levels) oximetry technique maps the T1 of administered hexamethyldisiloxane (HMDSO), an 1H NMR pO2 reporter molecule in about 3 ½ min. This allows us to subsequently monitor static and dynamic changes in the tissue pO2 (in response to intervention) at various locations due to the linear relationship between 1/T1 and pO2. In this work, an HMDSO-selective Look-Locker imaging sequence with EPI readout has been developed to enable faster PISTOL acquisitions. The new sequence incorporates the fast Look-Locker measurement method to enable T1, and hence, pO2 mapping of HMDSO in under one minute. To demonstrate the application of this pulse sequence in vivo, 50 μL of neat HMDSO was administered to the thigh muscle of a healthy rat (Fischer F344, n=4). Dynamic changes in the mean pO2 of the thigh muscle were measured using both PISTOL and the developed LL oximetry sequence in response to oxygen challenge and compared. Results demonstrate the efficacy of the new sequence in rapidly mapping the pO2 changes, leading to advances in fast quantitative 1H MR oximetry.

  11. 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

    Purpose: 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). Methods: The effects of imaging gradients...... 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...... in FEXI were observed on yeast cells. To analyze the AXR bias, signal evolution was calculated by applying matrix exponential operators. Results: 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...

  12. A motion correction framework for time series sequences in microscopy images.

    Science.gov (United States)

    Kumar, Ankur N; Short, Kurt W; Piston, David W

    2013-04-01

    With the advent of in vivo laser scanning fluorescence microscopy techniques, time-series and three-dimensional volumes of living tissue and vessels at micron scales can be acquired to firmly analyze vessel architecture and blood flow. Analysis of a large number of image stacks to extract architecture and track blood flow manually is cumbersome and prone to observer bias. Thus, an automated framework to accomplish these analytical tasks is imperative. The first initiative toward such a framework is to compensate for motion artifacts manifest in these microscopy images. Motion artifacts in in vivo microscopy images are caused by respiratory motion, heart beats, and other motions from the specimen. Consequently, the amount of motion present in these images can be large and hinders further analysis of these images. In this article, an algorithmic framework for the correction of time-series images is presented. The automated algorithm is comprised of a rigid and a nonrigid registration step based on shape contexts. The framework performs considerably well on time-series image sequences of the islets of Langerhans and provides for the pivotal step of motion correction in the further automatic analysis of microscopy images.

  13. Reconstructing Tone Sequences from Functional Magnetic Resonance Imaging Blood-Oxygen Level Dependent Responses within Human Primary Auditory Cortex

    Directory of Open Access Journals (Sweden)

    Kelly H. Chang

    2017-11-01

    Full Text Available Here we show that, using functional magnetic resonance imaging (fMRI blood-oxygen level dependent (BOLD responses in human primary auditory cortex, it is possible to reconstruct the sequence of tones that a person has been listening to over time. First, we characterized the tonotopic organization of each subject’s auditory cortex by measuring auditory responses to randomized pure tone stimuli and modeling the frequency tuning of each fMRI voxel as a Gaussian in log frequency space. Then, we tested our model by examining its ability to work in reverse. Auditory responses were re-collected in the same subjects, except this time they listened to sequences of frequencies taken from simple songs (e.g., “Somewhere Over the Rainbow”. By finding the frequency that minimized the difference between the model’s prediction of BOLD responses and actual BOLD responses, we were able to reconstruct tone sequences, with mean frequency estimation errors of half an octave or less, and little evidence of systematic biases.

  14. Single-Heartbeat Electromechanical Wave Imaging with Optimal Strain Estimation Using Temporally-Unequispaced Acquisition Sequences

    Science.gov (United States)

    Provost, Jean; Thiébaut, Stéphane; Luo, Jianwen; Konofagou, Elisa E.

    2014-01-01

    Electromechanical Wave Imaging (EWI) is a non-invasive, ultrasound-based imaging method capable of mapping the electromechanical wave (EW) in vivo, i.e., the transient deformations occurring in response to the electrical activation of the heart. Achieving the optimal imaging frame rates, in terms of the elastographic signal-to-noise ratio, to capture the EW in a full-view of the heart poses a technical challenge due to the limitations of conventional imaging sequences, in which the frame rate is low and tied to the imaging parameters. To achieve higher frame rates, EWI is typically performed in multiple small regions of interest acquired over separate heartbeats, which are then combined into a single view. However, the reliance on multiple heartbeats has previously precluded the method from its application in non-periodic arrhythmias such as fibrillation. Moreover, the frame rates achieved remain sub-optimal, because they are determined by the imaging parameters rather than being optimized to image the EW. In this paper, we develop a temporally-unequispaced acquisition sequence (TUAS) for which a wide range of frame rates are achievable independently of the imaging parameters, while maintaining a full view of the heart at high beam density. TUAS is first used to determine the optimal frame rate for EWI in a paced canine heart in vivo. The feasibility of performing single-heartbeat EWI during ventricular fibrillation is then demonstrated. These results indicate that EWI can be performed optimally, within a single heartbeat, during free breathing, and implemented in real time for periodic and non-periodic cardiac events. PMID:22297208

  15. Synthesis of image sequences for Korean sign language using 3D shape model

    Science.gov (United States)

    Hong, Mun-Ho; Choi, Chang-Seok; Kim, Chang-Seok; Jeon, Joon-Hyeon

    1995-05-01

    This paper proposes a method for offering information and realizing communication to the deaf-mute. The deaf-mute communicates with another person by means of sign language, but most people are unfamiliar with it. This method enables to convert text data into the corresponding image sequences for Korean sign language (KSL). Using a general 3D shape model of the upper body leads to generating the 3D motions of KSL. It is necessary to construct the general 3D shape model considering the anatomical structure of the human body. To obtain a personal 3D shape model, this general model is to adjust to the personal base images. Image synthesis for KSL consists of deforming a personal 3D shape model and texture-mapping the personal images onto the deformed model. The 3D motions for KSL have the facial expressions and the 3D movements of the head, trunk, arms and hands and are parameterized for easily deforming the model. These motion parameters of the upper body are extracted from a skilled signer's motion for each KSL and are stored to the database. Editing the parameters according to the inputs of text data yields to generate the image sequences of 3D motions.

  16. QUALITY ANALYSIS OF VEHICLE-BASED SEQUENCE IMAGES RELATIVE ORIENTATION BASED ON COMPUTER VISION

    Directory of Open Access Journals (Sweden)

    L. Yan

    2012-08-01

    Full Text Available Analyzed the quality and its influence factors of relative orientation of vehicle-based sequence images by comparing with the result obtained from Position & Orientation System using Direct Geo-referencing. Studies have shown that, under normal circumstances, the image Relative Orientation based on Computer vision is more robust, and under special conditions, it is more practical for analyzing and increasing the quality of vision measurement. Besides these, the method can be borrowed by many surveying and mapping related fields, taking indoor robot mobile environment awareness and unmanned automobile for instance.

  17. Position and Attitude Estimation from a Image Sequence of a Circle

    OpenAIRE

    佐藤, 真知子; Machiko, SATO; Tokyo Institute of Polytechnics Faculty of Engineering

    1995-01-01

    A method to estimate the position and attitude of a helicopter with respect to the landing site from a image sequence of a heliport is presented. The method use the circle of the heliport marking as the visual cue. The projection of the circle on the successive image taken by on board camera will change, therefore a Kalman filter can be build for the recursive estimation. The method needs to know just there is a circle ; The size of the circle is not necessary. The result of the experiment on...

  18. Comparison of Spoiled Gradient Echo and Steady-State Free-Precession Imaging for Native Myocardial T1 Mapping Using the Slice Interleaved T1 mapping (STONE) Sequence

    Science.gov (United States)

    Jang, Jihye; Bellm, Steven; Roujol, Sébastien; Basha, Tamer A.; Nezafat, Maryam; Kato, Shingo; Weingärtner, Sebastian; Nezafat, Reza

    2017-01-01

    Cardiac T1 mapping allows non-invasive imaging of interstitial diffuse fibrosis. Myocardial T1 is commonly calculated by voxel-wise fitting of the images acquired using balanced steady-state free precession (SSFP) after an inversion pulse. However, SSFP imaging is sensitive to B1 and B0 imperfection, which may result in additional artifacts. Gradient echo (GRE) imaging sequence has been used for myocardial T1 mapping, however its use has been limited to higher magnetic field to compensate for lower signal-to-noise ratio (SNR) of GRE vs. SSFP imaging. A slice-interleaved T1 mapping (STONE) sequence with SSFP readout (STONE-SSFP) has been recently proposed for native myocardial T1 mapping, which allows longer recovery of magnetization (>8 R-R) after each inversion pulse. In this study, we hypothesize that a longer recovery allows higher SNR and enables native myocardial T1 mapping using STONE with GRE imaging readout (STONE-GRE) at 1.5T. Numerical simulations, phantom and in-vivo imaging were performed to compare the performance of STONE-GRE and STONE-SSFP for native myocardial T1 mapping at 1.5T. In numerical simulations, STONE-SSFP shows sensitivity to both T2 and off-resonance. Despite insensitivity of GRE imaging to T2, STONE-GRE remains sensitive to T2 due to the dependence of the inversion pulse performance on T2. In the phantom study, STONE-GRE had inferior accuracy, precision, and similar repeatability as compared to STONE-SSFP. In in-vivo studies, STONE-GRE and STONE-SSFP had similar myocardial native T1 times, precision, repeatability and subjective T1 map quality. Despite lower SNR of GRE imaging readout compared to SSFP, STONE-GRE provides similar native myocardial T1 measurements, precision, repeatability and subjective image quality when compared to STONE-SSFP at 1.5T. PMID:27658506

  19. A wearable multi-channel fNIRS system for brain imaging in freely moving subjects.

    Science.gov (United States)

    Piper, Sophie K; Krueger, Arne; Koch, Stefan P; Mehnert, Jan; Habermehl, Christina; Steinbrink, Jens; Obrig, Hellmuth; Schmitz, Christoph H

    2014-01-15

    Functional near infrared spectroscopy (fNIRS) is a versatile neuroimaging tool with an increasing acceptance in the neuroimaging community. While often lauded for its portability, most of the fNIRS setups employed in neuroscientific research still impose usage in a laboratory environment. We present a wearable, multi-channel fNIRS imaging system for functional brain imaging in unrestrained settings. The system operates without optical fiber bundles, using eight dual wavelength light emitting diodes and eight electro-optical sensors, which can be placed freely on the subject's head for direct illumination and detection. Its performance is tested on N=8 subjects in a motor execution paradigm performed under three different exercising conditions: (i) during outdoor bicycle riding, (ii) while pedaling on a stationary training bicycle, and (iii) sitting still on the training bicycle. Following left hand gripping, we observe a significant decrease in the deoxyhemoglobin concentration over the contralateral motor cortex in all three conditions. A significant task-related ΔHbO2 increase was seen for the non-pedaling condition. Although the gross movements involved in pedaling and steering a bike induced more motion artifacts than carrying out the same task while sitting still, we found no significant differences in the shape or amplitude of the HbR time courses for outdoor or indoor cycling and sitting still. We demonstrate the general feasibility of using wearable multi-channel NIRS during strenuous exercise in natural, unrestrained settings and discuss the origins and effects of data artifacts. We provide quantitative guidelines for taking condition-dependent signal quality into account to allow the comparison of data across various levels of physical exercise. To the best of our knowledge, this is the first demonstration of functional NIRS brain imaging during an outdoor activity in a real life situation in humans. © 2013.

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

    Science.gov (United States)

    Nolte-Ernsting, C C; Tacke, J; Adam, G B; Haage, P; Jung, P; Jakse, G; Günther, R W

    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 urography, the entire pelvicaliceal system was imaged by acquisition of a fast single-slice sequence and the conventional 2D GRE technique provided superior morphological accuracy than 2D GRE EPI projection images (p excretory MR urography especially in old or critically ill patients unable to suspend breathing for more than 20 s. Conventional GRE sequences are superior to EPI in high-resolution detail MR urograms and in projection imaging.

  1. Rain or Snow Detection in Image Sequences through use of a Histogram of Orientation of Streaks

    OpenAIRE

    Bossu, Jérémie; Hautiere, Nicolas; TAREL, Jean Philippe

    2011-01-01

    The detection of bad weather conditions is crucial for meteorological centers, specially with demand for air, sea and ground traffic management. In this article, a system based on computer vision is presented which detects the presence of rain or snow. To separate the foreground from the background in image sequences, a classical Gaussian Mixture Model is used. The foreground model serves to detect rain and snow, since these are dynamic weather phenomena. Selection rules based on photometry a...

  2. 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 Impact factor: 2.225, year: 2016

  3. Prevalence of pathologic findings in asymptomatic knees of marathon runners before and after a competition in comparison with physically active subjects - a 3.0 T magnetic resonance imaging study

    Energy Technology Data Exchange (ETDEWEB)

    Stahl, Robert [University of California, San Francisco, Musculoskeletal and Quantitative Imaging Group, Department of Radiology, San Francisco, CA (United States); Ludwig Maximilians University of Munich, Department of Clinical Radiology, University Hospitals-Campus Grosshadern, Munich (Germany); Luke, Anthony [University of California, San Francisco, Department of Orthopedic Surgery, San Francisco, CA (United States); University of California, San Francisco, Department of Family and Community Medicine, San Francisco, CA (United States); Ma, C.B. [University of California, San Francisco, Department of Orthopedic Surgery, San Francisco, CA (United States); Krug, Roland; Steinbach, Lynne; Majumdar, Sharmila; Link, Thomas M. [University of California, San Francisco, Musculoskeletal and Quantitative Imaging Group, Department of Radiology, San Francisco, CA (United States)

    2008-07-15

    To determine the prevalence of pathologic findings in asymptomatic knees of marathon runners before and after a competition in comparison with physically active subjects. To compare the diagnostic performance of cartilage-dedicated magnetic resonance imaging (MRI) sequences at 3.0 T. Ten marathon runners underwent 3.0 T MRI 2-3 days before and after competition. Twelve physically active asymptomatic subjects not performing long-distance running were examined as controls. Pathologic condition was assessed with the whole-organ magnetic resonance imaging score (WORMS). Cartilage abnormalities and bone marrow edema pattern (BMEP) were quantified. Visualization of cartilage pathology was assessed with intermediate-weighted fast spin-echo (IM-w FSE), fast imaging employing steady-state acquisition (FIESTA) and T1-weighted three-dimensional (3D) high-spatial-resolution volumetric fat-suppressed spoiled gradient-echo (SPGR) MRI sequences. Eight of ten marathon runners and 7/12 controls showed knee abnormality. Slightly more and larger cartilage abnormalities, and BMEP, in marathon runners yielded higher but not significantly different WORMS (P > 0.05) than in controls. Running a single marathon did not alter MR findings substantially. Cartilage abnormalities were best visualized with IM-w FSE images (P < 0.05). A high prevalence of knee abnormalities was found in marathon runners and also in active subjects participating in other recreational sports. IM-w FSE sequences delineated more cartilage MR imaging abnormalities than did FIESTA and SPGR sequences. (orig.)

  4. Digitized hand-wrist radiographs: comparison of subjective and software-derived image quality at various compression ratios.

    Science.gov (United States)

    McCord, Layne K; Scarfe, William C; Naylor, Rachel H; Scheetz, James P; Silveira, Anibal; Gillespie, Kevin R

    2007-05-01

    The objectives of this study were to compare the effect of JPEG 2000 compression of hand-wrist radiographs on observer image quality qualitative assessment and to compare with a software-derived quantitative image quality index. Fifteen hand-wrist radiographs were digitized and saved as TIFF and JPEG 2000 images at 4 levels of compression (20:1, 40:1, 60:1, and 80:1). The images, including rereads, were viewed by 13 orthodontic residents who determined the image quality rating on a scale of 1 to 5. A quantitative analysis was also performed by using a readily available software based on the human visual system (Image Quality Measure Computer Program, version 6.2, Mitre, Bedford, Mass). ANOVA was used to determine the optimal compression level (P quality. When we used quantitative indexes, the JPEG 2000 images had lower quality at all compression ratios compared with the original TIFF images. There was excellent correlation (R2 >0.92) between qualitative and quantitative indexes. Image Quality Measure indexes are more sensitive than subjective image quality assessments in quantifying image degradation with compression. There is potential for this software-based quantitative method in determining the optimal compression ratio for any image without the use of subjective raters.

  5. Fully automated attenuation measurement and motion correction in FLIP image sequences.

    Science.gov (United States)

    van de Giessen, Martijn; van der Laan, Annelies; Hendriks, Emile A; Vidorreta, Marta; Reiber, Johan H C; Jost, Carolina R; Tanke, Hans J; Lelieveldt, Boudewijn P F

    2012-02-01

    Fluorescence loss in photobleaching (FLIP) is a method to study compartment connectivity in living cells. A FLIP sequence is obtained by alternatively bleaching a spot in a cell and acquiring an image of the complete cell. Connectivity is estimated by comparing fluorescence signal attenuation in different cell parts. The measurements of the fluorescence attenuation are hampered by the low signal to noise ratio of the FLIP sequences, by sudden sample shifts and by sample drift. This paper describes a method that estimates the attenuation by modeling photobleaching as exponentially decaying signals. Sudden motion artifacts are minimized by registering the frames of a FLIP sequence to target frames based on the estimated model and by removing frames that contain deformations. Linear motion (sample drift) is reduced by minimizing the entropy of the estimated attenuation coefficients. Experiments on 16 in vivo FLIP sequences of muscle cells in Drosophila show that the proposed method results in fluorescence attenuations similar to the manually identified gold standard, but with standard deviations of approximately 50 times smaller. As a result of this higher precision, cell compartment edges and details such as cell nuclei become clearly discernible. The main value of this method is that it uses a model of the bleaching process to correct motion and that the model based fluorescence intensity and attenuation estimates can be interpreted easily. The proposed method is fully automatic, and runs in approximately one minute per sequence, making it suitable for unsupervised batch processing of large data series.

  6. A Bayesian framework for human body pose tracking from depth image sequences.

    Science.gov (United States)

    Zhu, Youding; Fujimura, Kikuo

    2010-01-01

    This paper addresses the problem of accurate and robust tracking of 3D human body pose from depth image sequences. Recovering the large number of degrees of freedom in human body movements from a depth image sequence is challenging due to the need to resolve the depth ambiguity caused by self-occlusions and the difficulty to recover from tracking failure. Human body poses could be estimated through model fitting using dense correspondences between depth data and an articulated human model (local optimization method). Although it usually achieves a high accuracy due to dense correspondences, it may fail to recover from tracking failure. Alternately, human pose may be reconstructed by detecting and tracking human body anatomical landmarks (key-points) based on low-level depth image analysis. While this method (key-point based method) is robust and recovers from tracking failure, its pose estimation accuracy depends solely on image-based localization accuracy of key-points. To address these limitations, we present a flexible Bayesian framework for integrating pose estimation results obtained by methods based on key-points and local optimization. Experimental results are shown and performance comparison is presented to demonstrate the effectiveness of the proposed approach.

  7. A Bayesian Framework for Human Body Pose Tracking from Depth Image Sequences

    Directory of Open Access Journals (Sweden)

    Youding Zhu

    2010-05-01

    Full Text Available This paper addresses the problem of accurate and robust tracking of 3D human body pose from depth image sequences. Recovering the large number of degrees of freedom in human body movements from a depth image sequence is challenging due to the need to resolve the depth ambiguity caused by self-occlusions and the difficulty to recover from tracking failure. Human body poses could be estimated through model fitting using dense correspondences between depth data and an articulated human model (local optimization method. Although it usually achieves a high accuracy due to dense correspondences, it may fail to recover from tracking failure. Alternately, human pose may be reconstructed by detecting and tracking human body anatomical landmarks (key-points based on low-level depth image analysis. While this method (key-point based method is robust and recovers from tracking failure, its pose estimation accuracy depends solely on image-based localization accuracy of key-points. To address these limitations, we present a flexible Bayesian framework for integrating pose estimation results obtained by methods based on key-points and local optimization. Experimental results are shown and performance comparison is presented to demonstrate the effectiveness of the proposed approach.

  8. A Bayesian Framework for Human Body Pose Tracking from Depth Image Sequences

    Science.gov (United States)

    Zhu, Youding; Fujimura, Kikuo

    2010-01-01

    This paper addresses the problem of accurate and robust tracking of 3D human body pose from depth image sequences. Recovering the large number of degrees of freedom in human body movements from a depth image sequence is challenging due to the need to resolve the depth ambiguity caused by self-occlusions and the difficulty to recover from tracking failure. Human body poses could be estimated through model fitting using dense correspondences between depth data and an articulated human model (local optimization method). Although it usually achieves a high accuracy due to dense correspondences, it may fail to recover from tracking failure. Alternately, human pose may be reconstructed by detecting and tracking human body anatomical landmarks (key-points) based on low-level depth image analysis. While this method (key-point based method) is robust and recovers from tracking failure, its pose estimation accuracy depends solely on image-based localization accuracy of key-points. To address these limitations, we present a flexible Bayesian framework for integrating pose estimation results obtained by methods based on key-points and local optimization. Experimental results are shown and performance comparison is presented to demonstrate the effectiveness of the proposed approach. PMID:22399933

  9. Norms for name agreement, familiarity, subjective frequency, and imageability for 348 object names in Tunisian Arabic.

    Science.gov (United States)

    Boukadi, Mariem; Zouaidi, Cirine; Wilson, Maximiliano A

    2016-06-01

    Normative databases for pictorial stimuli are widely used in research on language processing in order to control for a number of psycholinguistic variables in the selected stimuli. Such resources are lacking for Arabic and its dialectal varieties. In the present study, we aimed to provide Tunisian Arabic (TA) normative data for 348 line drawings taken from Cycowicz, Friedman, Rothstein, and Snodgrass (1997), which include Snodgrass and Vanderwart's (1980) 260 pictures. Norms were collected for the following psycholinguistic variables: name agreement, familiarity, subjective frequency, and imageability. Word length data (in numbers of phonemes and syllables) are also listed in the database. We investigated the effects of these variables on word reading in TA. We found that word length and frequency were the best predictors of word-reading latencies in TA. Name agreement was also a significant predictor of word-reading latencies. A particularly interesting finding was that the semantic variables, imageability and familiarity, affected word-reading latencies in TA. Thus, it would seem that TA readers rely on semantics even when reading individual Arabic words that are transparent in terms of orthography-to-phonology mappings. This database represents a precious and much-needed psycholinguistic resource for researchers investigating language processing in Arabic-speaking populations.

  10. Prevalence of Sinusitis Detected by Magnetic Resonance Imaging in Subjects with Dementia or Alzheimer's Disease.

    Science.gov (United States)

    Yasue, Minori; Sugiura, Saiko; Uchida, Yasue; Otake, Hironao; Teranishi, Masaaki; Sakurai, Takashi; Toba, Kenji; Shimokata, Hiroshi; Ando, Fujiko; Otsuka, Rei; Nakashima, Tsutomu

    2015-01-01

    It has been reported that periodontitis is associated with Alzheimer's disease. However, the association between paranasal sinusitis and Alzheimer's disease has not been studied, although olfactory dysfunction frequently precedes the progress of dementia or Alzheimer's disease. We studied 783 patients (283 men, 500 women; mean age 77.0 ± 7.9 years) who visited the Center for Comprehensive Care and Research on Memory Disorders, National Center for Geriatrics and Gerontology, and 2139 control subjects who participated in a population-based study conducted by the National Institute for Longevity Sciences - Longitudinal Study of Aging (NILS-LSA) in Japan. Sinusitis was evaluated using magnetic resonance imaging (MRI) according to the Lund-Mackay scoring system. A sinusitis score of ≥ 4 was classified as positive and a score of ≤ 3 was classified as negative. The prevalence of positive sinusitis was 6.3% in patients with a mini-mental state examination (MMSE) score of sinusitis was7.2% in the control group. The prevalence of sinusitis was not significantly different between normal controls and patients with dementia or Alzheimer's disease after adjustments for age and sex. The rate of positive sinusitis was higher in male than in female subjects in both groups. The prevalence of sinusitis in patients with Alzheimer's disease or dementia was not higher than in the general population.

  11. Serum lipidomics meets cardiac magnetic resonance imaging: profiling of subjects at risk of dilated cardiomyopathy.

    Directory of Open Access Journals (Sweden)

    Marko Sysi-Aho

    Full Text Available Dilated cardiomyopathy (DCM, characterized by left ventricular dilatation and systolic dysfunction, constitutes a significant cause for heart failure, sudden cardiac death or need for heart transplantation. Lamin A/C gene (LMNA on chromosome 1p12 is the most significant disease gene causing DCM and has been reported to cause 7-9% of DCM leading to cardiac transplantation. We have previously performed cardiac magnetic resonance imaging (MRI to LMNA carriers to describe the early phenotype. Clinically, early recognition of subjects at risk of developing DCM would be important but is often difficult. Thus we have earlier used the MRI findings of these LMNA carriers for creating a model by which LMNA carriers could be identified from the controls at an asymptomatic stage. Some LMNA mutations may cause lipodystrophy. To characterize possible effects of LMNA mutations on lipid profile, we set out to apply global serum lipidomics using Ultra Performance Liquid Chromatography coupled to mass spectrometry in the same LMNA carriers, DCM patients without LMNA mutation and controls. All DCM patients, with or without LMNA mutation, differed from controls in regard to distinct serum lipidomic profile dominated by diminished odd-chain triglycerides and lipid ratios related to desaturation. Furthermore, we introduce a novel approach to identify associations between the molecular lipids from serum and the MR images from the LMNA carriers. The association analysis using dependency network and regression approaches also helped us to obtain novel insights into how the affected lipids might relate to cardiac shape and volume changes. Our study provides a framework for linking serum derived molecular markers not only with clinical endpoints, but also with the more subtle intermediate phenotypes, as derived from medical imaging, of potential pathophysiological relevance.

  12. Independent component model for cognitive functions of multiple subjects using [15O]H2O PET images.

    Science.gov (United States)

    Park, Hae-Jeong; Kim, Jae-Jin; Youn, Tak; Lee, Dong Soo; Lee, Myung Chul; Kwon, Jun Soo

    2003-04-01

    An independent component model of multiple subjects' positron emission tomography (PET) images is proposed to explore the overall functional components involved in a task and to explain subject specific variations of metabolic activities under altered experimental conditions utilizing the Independent component analysis (ICA) concept. As PET images represent time-compressed activities of several cognitive components, we derived a mathematical model to decompose functional components from cross-sectional images based on two fundamental hypotheses: (1) all subjects share basic functional components that are common to subjects and spatially independent of each other in relation to the given experimental task, and (2) all subjects share common functional components throughout tasks which are also spatially independent. The variations of hemodynamic activities according to subjects or tasks can be explained by the variations in the usage weight of the functional components. We investigated the plausibility of the model using serial cognitive experiments of simple object perception, object recognition, two-back working memory, and divided attention of a syntactic process. We found that the independent component model satisfactorily explained the functional components involved in the task and discuss here the application of ICA in multiple subjects' PET images to explore the functional association of brain activations. Copyright 2003 Wiley-Liss, Inc.

  13. 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

  14. BOLD imaging in the mouse brain using a turboCRAZED sequence at high magnetic fields.

    Science.gov (United States)

    Schneider, Johannes T; Faber, Cornelius

    2008-10-01

    Functional MRI (fMRI) based on the detection of intermolecular double-quantum coherences (iDQC) has previously been shown to provide pronounced activation signal. For fMRI in small animals at very high magnetic fields, the essential fast gradient echo-based readout methods become problematic. Here, rapid intermolecular double-quantum coherence (iDQC) imaging was implemented, combining the iDQC preparation sequence with a Turbo spin echo-like readout. Four-step phase cycling and a novel intensity-ordered k-space encoding scheme with separate acquisition of odd and even echoes were essential to optimize signal to noise ratio efficiency. Compared with a single echo readout of iDQC signal, acceleration of factor 16 was achieved in phantoms using the novel method at 17.6 Tesla. In vivo, echo trains consisting of 32 echoes were possible and images of the mouse brain were obtained in 30 s. The blood oxygen level dependent (BOLD) effect in the mouse brain upon change of breathing gas was observed as average signal change of (6.3 +/- 1.1)% in iDQC images. Signal changes in conventional multi spin echo images were (4.4 +/- 2.3)% and (8.3 +/- 3.8)% with gradient echo methods. Combination of T(2)*-weighting with the fast iDQC sequence may yield higher signal changes than with either method alone, and establish fast iDQC imaging a robust tool for high field fMRI in small animals. (c) 2008 Wiley-Liss, Inc.

  15. 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.

  16. Temporal statistics of natural image sequences generated by movements with insect flight characteristics.

    Directory of Open Access Journals (Sweden)

    Alexander Schwegmann

    Full Text Available Many flying insects, such as flies, wasps and bees, pursue a saccadic flight and gaze strategy. This behavioral strategy is thought to separate the translational and rotational components of self-motion and, thereby, to reduce the computational efforts to extract information about the environment from the retinal image flow. Because of the distinguishing dynamic features of this active flight and gaze strategy of insects, the present study analyzes systematically the spatiotemporal statistics of image sequences generated during saccades and intersaccadic intervals in cluttered natural environments. We show that, in general, rotational movements with saccade-like dynamics elicit fluctuations and overall changes in brightness, contrast and spatial frequency of up to two orders of magnitude larger than translational movements at velocities that are characteristic of insects. Distinct changes in image parameters during translations are only caused by nearby objects. Image analysis based on larger patches in the visual field reveals smaller fluctuations in brightness and spatial frequency composition compared to small patches. The temporal structure and extent of these changes in image parameters define the temporal constraints imposed on signal processing performed by the insect visual system under behavioral conditions in natural environments.

  17. Effect of the Parent-Adolescent Relationship on Adolescent Boys' Body Image and Subjective Well-Being.

    Science.gov (United States)

    Walter, Ofra; Shenaar-Golan, Vered

    2017-07-01

    Adolescent boys must cope with physical changes that hamper their ability to form a positive body image. Sociocultural messages influence the concepts of body image, personal appearance, and weight, encouraging men to develop lean and muscular bodies. The current study examined adolescent boys' body image and its relationship to their subjective well-being (SWB) and the effect of the parent-adolescent relationship on body image and SWB. Participating in the research were 107 adolescent boys in Israel, aged 13 to 18 years. Four questionnaires were utilized: demographic, body mass index, Body Investment Scale, and Personal Well-Being Index. The findings indicate a significant, medium positive correlation between SWB and body image. After controlling for the variable of parent-adolescent relationship, the correlation weakened, indicating that the parent-adolescent relationship has no effect on adolescent boys' SWB and body image. Body image was reported to be a predictor of SWB.

  18. Effect of the Parent–Adolescent Relationship on Adolescent Boys’ Body Image and Subjective Well-Being

    Science.gov (United States)

    Walter, Ofra; Shenaar-Golan, Vered

    2017-01-01

    Adolescent boys must cope with physical changes that hamper their ability to form a positive body image. Sociocultural messages influence the concepts of body image, personal appearance, and weight, encouraging men to develop lean and muscular bodies. The current study examined adolescent boys’ body image and its relationship to their subjective well-being (SWB) and the effect of the parent–adolescent relationship on body image and SWB. Participating in the research were 107 adolescent boys in Israel, aged 13 to 18 years. Four questionnaires were utilized: demographic, body mass index, Body Investment Scale, and Personal Well-Being Index. The findings indicate a significant, medium positive correlation between SWB and body image. After controlling for the variable of parent–adolescent relationship, the correlation weakened, indicating that the parent–adolescent relationship has no effect on adolescent boys’ SWB and body image. Body image was reported to be a predictor of SWB. PMID:28625112

  19. It’s all in the past: Temporal-context effects modulate subjective evaluations of emotional visual stimuli, regardless of presentation sequence

    Czech Academy of Sciences Publication Activity Database

    Czekóová, K.; Shaw, D. J.; Janoušová, E.; Urbánek, Tomáš

    2015-01-01

    Roč. 6, č. 367 (2015), s. 1-11 ISSN 1664-1078 Institutional support: RVO:68081740 Keywords : emotion * temporal context * presentation sequence * assimilation effect * contrast effect Subject RIV: AN - Psychology Impact factor: 2.463, year: 2015 http://journal.frontiersin.org/article/10.3389/fpsyg.2015.00367/full

  20. Comparison of GRASE and turbo spin echo sequences in brain MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong Youk; Lee, Young Joon; Eun, Choong Ki; Jeon, Young Seup; Kim, Ig Dae; Cha, Seong Sook [Inje Univ., Pusan (Korea, Republic of). Coll. of Medicine

    1998-04-01

    The purpose of this study was to evaluate the utility of GRASE images of the brain, which combine gradient echo-EPI and turbo spin echo, and to compare the results with those of the turbo spin echo (TSE) technique. We analyzed and compared brain MR images obtained in 25 patients between October, 1996 and January, 1997, both TSE and GRASE techniques. Diagnosis was normal (n=5), infarct or ischemia (n=10), intracerebral hemorrhage (n=6), and neoplasm (n=4). TSE and GRASE MR images were obtained using a 1.5 T Gyroscan ACS-NT (Philips, Netherlands). For qualitative assessment, overall image quality, discrimination between cortical gray-white matter and basal ganglia-white matter, lesion conspicuity, and MR artifact were evaluated using a subjective grading system ranging from 1 to 5 (1=TSE better than GRASE, 5=GRASE better than TSE). For quantitative assessment, signal-to-noise ratios (SNRs) were calculated for cortical gray matter, white matter, basal ganglia, and lesions, and contrast-to-noise ratios (CNRs) were calculated for cortical gray-white matter, basal ganglia-white matter and lesions-white matter. We measured image acquisition time and RF specific absorption rate (SAR) on TSE and GRASE. With regard to MR artifact, GRASE is more sensitive than TSE, but as regards image quality and lesion distinction, the two modalities show no distinct difference. Since GRASE is superior to TSE for the detection of hemosiderin, and image acquisition time is three times shorter using GRASE, GRASE might usefully be applied during the evaluation by MR imaging of certain brain conditions. (author). 17 refs., 3 tabs., 5 figs.

  1. Update on MRI Pulse Sequences for the Knee: Imaging of Cartilage, Meniscus, Tendon, and Hardware.

    Science.gov (United States)

    Ariyachaipanich, Aticha; Bae, Won C; Statum, Sheronda; Chung, Christine B

    2017-04-01

    Magnetic resonance imaging (MRI) is widely used in the clinical setting as well as for research applications. Since its inception, technical development has broadly progressed as a response to challenges in both the clinical and research settings. Higher magnetic field strength and advances in hardware and software have revolutionized the diagnostic potential of MRI and moved well beyond diagnosis to characterization of tissue metabolism, biochemistry, disease pathogenesis, and material property, to name a few. This article focuses on state-of-the-art clinical and cutting-edge novel pulse sequences applied to knee MRI. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  2. Novel permutation-diffusion image encryption algorithm with chaotic dynamic S-box and DNA sequence operation

    Science.gov (United States)

    Tian, Ye; Lu, Zhimao

    2017-08-01

    The development of the computer network makes image files transportation via network become more and more convenient. This paper is concerned with the image encryption algorithm design based on the chaotic S-box mechanism. This paper proposes an Image Encryption algorithm involving both chaotic dynamic S-boxes and DNA sequence operation(IESDNA). The contribution of this paper is three folded: Firstly, we design an external 256-bit key to get large key space; secondly, we design a chaotic system to scramble image pixels; thirdly, DNA sequence operations are adopted to diffuse the scrambled image pixels. Experimental results show that our proposed image encryption algorithm can meet multiple cryptographic criteria and obtain good image encryption effect.

  3. 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...... and temporal perceptual information. Those features are then mapped, using a machine learning (ML) algorithm, the Support Vector Regression (SVR), to the quality scores of Full Reference (FR) quality metrics. The novelty of this work is to design a NR framework for the prediction of quality metrics by applying...... with the true FR quality metrics scores of four images metrics: PSNR, NQM, SSIM and UQI and one video metric: VQM. Results show that our technique achieves a fairly reasonable performance. The improved performance obtained in SROCC and LCC is up to 0.99 and the RMSE is reduced to as little as 0.01 between...

  4. Bubbles: a unifying framework for low-level statistical properties of natural image sequences.

    Science.gov (United States)

    Hyvärinen, Aapo; Hurri, Jarmo; Väyrynen, Jaakko

    2003-07-01

    Recently, different models of the statistical structure of natural images have been proposed. These models predict properties of biological visual systems and can be used as priors in Bayesian inference. The fundamental model is independent component analysis, which can be estimated by maximization of the sparsenesses of linear filter outputs. This leads to the emergence of principal simple cell properties. Alternatively, simple cell properties are obtained by maximizing the temporal coherence in natural image sequences. Taking account of the basic dependencies of linear filter outputs permit modeling of complex cells and topographic organization as well. We propose a unifying framework for these statistical properties, based on the concept of spatiotemporal activity "bubbles."A bubble means here an activation of simple cells (linear filters) that is contiguous both in space (the cortical surface) and in time.

  5. Temporal and spatiotemporal coherence in simple-cell responses: a generative model of natural image sequences.

    Science.gov (United States)

    Hurri, Jarmo; Hyvärinen, Aapo

    2003-08-01

    We present a two-layer dynamic generative model of the statistical structure of natural image sequences. The second layer of the model is a linear mapping from simple-cell outputs to pixel values, as in most work on natural image statistics. The first layer models the dependencies of the activity levels (amplitudes or variances) of the simple cells, using a multivariate autoregressive model. The second layer shows the emergence of basis vectors that are localized, oriented and have different scales, just like in previous work. But in our new model, the first layer learns connections between the simple cells that are similar to complex cell pooling: connections are strong among cells with similar preferred location, frequency and orientation. In contrast to previous work in which one of the layers needed to be fixed in advance, the dynamic model enables us to estimate both of the layers simultaneously from natural data.

  6. 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.)

  7. Diffusion-weighted imaging of the sellar region: A comparison study of BLADE and single-shot echo planar imaging sequences

    Energy Technology Data Exchange (ETDEWEB)

    Yiping, Lu [Department of Radiology, Huashan Hospital, Fudan University, 12 Wulumuqi Rd. Middle, Shanghai 200040 (China); Hui, Liu [MR Collaboration NE Asia, Siemens Healthcare, Siemens Ltd., China, Shanghai 201318 (China); Kun, Zhou [MR PLM APPL, Siemens Shenzhen Magnetic Resonance Ltd., Shenzhen 518057 (China); Daoying, Geng, E-mail: GengdaoyingGDY@163.com [Department of Radiology, Huashan Hospital, Fudan University, 12 Wulumuqi Rd. Middle, Shanghai 200040 (China); Bo, Yin, E-mail: yinbo7@163.com [Department of Radiology, Huashan Hospital, Fudan University, 12 Wulumuqi Rd. Middle, Shanghai 200040 (China)

    2014-07-15

    Purpose: The purpose of this study is to compare BLADE diffusion-weighted imaging (DWI) with single-shot echo planar imaging (EPI) DWI on the aspects of feasibility of imaging the sellar region and image quality. Methods: A total of 3 healthy volunteers and 52 patients with suspected lesions in the sellar region were included in this prospective intra-individual study. All exams were performed at 3.0 T with a BLADE DWI sequence and a standard single-shot EP-DWI sequence. Phantom measurements were performed to measure the objective signal-to-noise ratio (SNR). Two radiologists rated the image quality according to the visualisation of the internal carotid arteries, optic chiasm, pituitary stalk, pituitary gland and lesion, and the overall image quality. One radiologist measured lesion sizes for detecting their relationship with the image score. Results: The SNR in BLADE DWI sequence showed no significant difference from the single-shot EPI sequence (P > 0.05). All of the assessed regions received higher scores in BLADE DWI images than single-shot EP-DWI.

  8. Novel Spatiotemporal Filter for Dim Point Targets Detection in Infrared Image Sequences

    Directory of Open Access Journals (Sweden)

    Zhaohui Li

    2015-01-01

    Full Text Available Dim point target detection is of great importance in both civil and military fields. In this paper a novel spatiotemporal filter is proposed to incorporate both the spatial and temporal features of moving dim point targets. Since targets are expected to be detected as far as possible, in this situation, they have no texture features in spatial dimensions, appearing like isolated points. Based on the attributes, potential targets are extracted by searching the local maximum point in a sliding window. And the potential targets are then correlated based on target moving patterns. After combining local maximum points and target moving patterns, structure background in infrared scene is removed. Next, the temporal profiles of infrared sense are reviewed and examined. By a new max-median filter performing on temporal profiles, the intensity of target pulse signal is extracted. Finally, each temporal profile is divided into several pieces to estimate the variance of the temporal profiles, which leads to a new detection metric. The proposed approach is tested via several infrared image sequences. The results show that our proposed method can significantly reduce the complex background in aerial infrared image sequence and have a good detection performance.

  9. 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.

  10. Intra-Rater Reliability of Rehabilitative Ultrasound Imaging for Multifidus Muscles Thickness and Cross Section Area in Healthy Subjects

    OpenAIRE

    Hosseinifar, Mohammad; Akbari, Asghar; Ghiasi, Fateme

    2015-01-01

    Introduction: Rehabilitative Ultrasound Imaging (RUSI) must be valuable method for research and rehabilitation. So, the reliability of its measurements must be determined. The purpose of this study was to evaluate the intra-rater reliability of RUSI for measurement of multifidus (MF) muscles cross section areas (CSAs), bladder wall diameter, and thickness of MF muscles between 2 sessions in healthy subjects. Method: Fifteen healthy subjects through simple non-probability sampling participated...

  11. 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.

  12. Motion parameter estimation by tracking stationary three-dimensional straight lines in image sequences

    Science.gov (United States)

    Habib, Ayman

    The purpose of this work is to utilize extracted linear features from imagery collected by a Mobile Mapping System (MMS) for the purpose of motion parameter estimation. The MMS is assumed to be equipped with two or more cameras. The relative relationship between these cameras is rigid, i.e. it does not change from one epoch to the other and can be determined by a calibration procedure. An optimal (minimal) representation of 3-D straight lines that requires only four parameters is discussed. The perspective transformation of the extracted linear features back and forth between image and object space is derived. By tracking stationary linear features in successive image sequences, the motion parameters, rotation and displacement, between the system's position at the corresponding epochs can be estimated. The suggested algorithm works as follows. First, straight-line features are extracted from the imagery. Then, a model space coordinate system is defined for each system position at which an image set is collected. The origin of this system can be chosen as the perspective center of one of the cameras onboard. Then, the linear features in successive image sets are projected into the corresponding model space. It has to be noted that the projection procedure is performed separately for the image sets under consideration. The mathematical model that relates the parameters of the resulting conjugate lines to the motion parameters of the system is derived. The relationship is obtained by imposing four constraints on the four degrees of freedom of any conjugate lines. The suggested algorithm is used to estimate the motion parameters using conjugate linear features in successive stereo-pairs collected by the GPS van of the Ohio State University. This algorithm will be helpful in deriving the motion parameters of the vehicle during periods of failure of the positioning component onboard, e.g. GPS loss of lock for a long time interval.

  13. Assessment of cartilage-dedicated sequences at ultra-high-field MRI: comparison of imaging performance and diagnostic confidence between 3.0 and 7.0 T with respect to osteoarthritis-induced changes at the knee joint

    Energy Technology Data Exchange (ETDEWEB)

    Stahl, Robert [University of California, Musculoskeletal and Quantitative Imaging Group, Department of Radiology, San Francisco, CA (United States); University Hospitals - Campus Grosshadern, Ludwig Maximilians University of Munich, Department of Clinical Radiology, Munich (Germany); Krug, Roland; Zuo, Jin; Majumdar, Sharmila; Link, Thomas M. [University of California, Musculoskeletal and Quantitative Imaging Group, Department of Radiology, San Francisco, CA (United States); Kelley, Douglas A.C. [General Electrics Healthcare Technologies, San Francisco, CA (United States); Ma, C.B. [University of California, Department of Orthopedic Surgery, San Francisco, CA (United States)

    2009-08-15

    The objectives of the study were to optimize three cartilage-dedicated sequences for in vivo knee imaging at 7.0 T ultra-high-field (UHF) magnetic resonance imaging (MRI) and to compare imaging performance and diagnostic confidence concerning osteoarthritis (OA)-induced changes at 7.0 and 3.0 T MRI. Optimized MRI sequences for cartilage imaging at 3.0 T were tailored for 7.0 T: an intermediate-weighted fast spin-echo (IM-w FSE), a fast imaging employing steady-state acquisition (FIESTA) and a T1-weighted 3D high-spatial-resolution volumetric fat-suppressed spoiled gradient-echo (SPGR) sequence. Three healthy subjects and seven patients with mild OA were examined. Signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), diagnostic confidence in assessing cartilage abnormalities, and image quality were determined. Abnormalities were assessed with the whole organ magnetic resonance imaging score (WORMS). Focal cartilage lesions and bone marrow edema pattern (BMEP) were also quantified. At 7.0 T, SNR was increased (p<0.05) for all sequences. For the IM-w FSE sequence, limitations with the specific absorption rate (SAR) required modifications of the scan parameters yielding an incomplete coverage of the knee joint, extensive artifacts, and a less effective fat saturation. CNR and image quality were increased (p<0.05) for SPGR and FIESTA and decreased for IM-w FSE. Diagnostic confidence for cartilage lesions was highest (p<0.05) for FIESTA at 7.0 T. Evaluation of BMEP was decreased (p < 0.05) at 7.0 T due to limited performance of IM-w FSE. Gradient echo-based pulse sequences like SPGR and FIESTA are well suited for imaging at UHF which may improve early detection of cartilage lesions. However, UHF IM-w FSE sequences are less feasible for clinical use. (orig.)

  14. 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.)

  15. Change Blindness Is Influenced by Both Contrast Energy and Subjective Importance within Local Regions of the Image.

    Science.gov (United States)

    Zuiderbaan, Wietske; van Leeuwen, Jonathan; Dumoulin, Serge O

    2017-01-01

    Our visual system receives an enormous amount of information, but not all information is retained. This is exemplified by the fact that subjects fail to detect large changes in a visual scene, i.e., change-blindness. Current theories propose that our ability to detect these changes is influenced by the gist or interpretation of an image. On the other hand, stimulus-driven image features such as contrast energy dominate the representation in early visual cortex (De Valois and De Valois, 1988; Boynton et al., 1999; Olman et al., 2004; Mante and Carandini, 2005; Dumoulin et al., 2008). Here we investigated whether contrast energy contributes to our ability to detect changes within a visual scene. We compared the ability to detect changes in contrast energy together with changes to a measure of the interpretation of an image. We used subjective important aspects of the image as a measure of the interpretation of an image. We measured reaction times while manipulating the contrast energy and subjective important properties using the change blindness paradigm. Our results suggest that our ability to detect changes in a visual scene is not only influenced by the subjective importance, but also by contrast energy. Also, we find that contrast energy and subjective importance interact. We speculate that contrast energy and subjective important properties are not independently represented in the visual system. Thus, our results suggest that the information that is retained of a visual scene is both influenced by stimulus-driven information as well as the interpretation of a scene.

  16. Change Blindness Is Influenced by Both Contrast Energy and Subjective Importance within Local Regions of the Image

    Directory of Open Access Journals (Sweden)

    Wietske Zuiderbaan

    2017-10-01

    Full Text Available Our visual system receives an enormous amount of information, but not all information is retained. This is exemplified by the fact that subjects fail to detect large changes in a visual scene, i.e., change-blindness. Current theories propose that our ability to detect these changes is influenced by the gist or interpretation of an image. On the other hand, stimulus-driven image features such as contrast energy dominate the representation in early visual cortex (De Valois and De Valois, 1988; Boynton et al., 1999; Olman et al., 2004; Mante and Carandini, 2005; Dumoulin et al., 2008. Here we investigated whether contrast energy contributes to our ability to detect changes within a visual scene. We compared the ability to detect changes in contrast energy together with changes to a measure of the interpretation of an image. We used subjective important aspects of the image as a measure of the interpretation of an image. We measured reaction times while manipulating the contrast energy and subjective important properties using the change blindness paradigm. Our results suggest that our ability to detect changes in a visual scene is not only influenced by the subjective importance, but also by contrast energy. Also, we find that contrast energy and subjective importance interact. We speculate that contrast energy and subjective important properties are not independently represented in the visual system. Thus, our results suggest that the information that is retained of a visual scene is both influenced by stimulus-driven information as well as the interpretation of a scene.

  17. Technical innovation in dynamic contrast-enhanced magnetic resonance imaging of musculoskeletal tumors: an MR angiographic sequence using a sparse k-space sampling strategy.

    Science.gov (United States)

    Fayad, Laura M; Mugera, Charles; Soldatos, Theodoros; Flammang, Aaron; del Grande, Filippo

    2013-07-01

    We demonstrate the clinical use of an MR angiography sequence performed with sparse k-space sampling (MRA), as a method for dynamic contrast-enhanced (DCE)-MRI, and apply it to the assessment of sarcomas for treatment response. Three subjects with sarcomas (2 with osteosarcoma, 1 with high-grade soft tissue sarcomas) underwent MRI after neoadjuvant therapy/prior to surgery, with conventional MRI (T1-weighted, fluid-sensitive, static post-contrast T1-weighted sequences) and DCE-MRI (MRA, time resolution = 7-10 s, TR/TE 2.4/0.9 ms, FOV 40 cm(2)). Images were reviewed by two observers in consensus who recorded image quality (1 = diagnostic, no significant artifacts, 2 = diagnostic, 75 % with good response, >75 % with poor response). DCE-MRI findings were concordant with histological response (arterial enhancement with poor response, no arterial enhancement with good response). Unlike conventional DCE-MRI sequences, an MRA sequence with sparse k-space sampling is easily integrated into a routine musculoskeletal tumor MRI protocol, with high diagnostic quality. In this preliminary work, tumor enhancement characteristics by DCE-MRI were used to assess treatment response.

  18. Influence of cognitive strategies on the pattern of cortical activation during mental subtraction. A functional imaging study in human subjects.

    Science.gov (United States)

    Burbaud, P; Camus, O; Guehl, D; Bioulac, B; Caillé, J; Allard, M

    2000-06-16

    Functional magnetic resonance imaging (fMRI) at 1.5 T was used to investigate the influence of cognitive strategies on cortical activation during mental calculation. Twenty-nine right-handed subjects performed a serial subtraction of prime numbers. Even though a common corpus of brain areas was activated during this mental calculation, differences appeared between subjects in function of their spontaneous cognitive strategy. In subjects using a so called verbal strategy (n=15), the main activation was located in the whole left dorsolateral frontal cortex with a little activation of the inferior parietal cortex. In subjects using a so called visual strategy (n=14), a bilateral activation in the prefrontal cortex and a high activation in the left inferior parietal cortex were observed. These results demonstrate that numbers are processed through a distributed network of cortical areas, the lateralization of which is clearly influenced by subject strategy.

  19. FDG-PET imaging in HIV-infected subjects: relation with therapy and immunovirological variables

    Energy Technology Data Exchange (ETDEWEB)

    Lucignani, Giovanni; Orunesu, Eva [Neurological Institute Milan, Laboratory of Cellular Neurophysiology, IRCCS Foundation, Milan (Italy); Cesari, Miriam [Univ. of Milan (Italy). Dept. of Clinical Science; Marzo, Katia; Chiti, Arturo [IRCCS Humanitas, Milan (Italy). Dept. of Nuclear Medicine; Pacei, Michela [Milan Univ. (Italy). Lab. of Immunology; Bechi, Giulia [IRCCS Foundation, Milan (Italy). Lab. of Cellular Neurophysiology; Gori, Andrea [Univ. of Milan Biococca, Monza (Italy). Inst. of Infectious Disseases; Gaito, Sabrina [Milan Univ. (Italy). Dept. of Computer Science; Clerici, Mario [Milan Univ. (Italy). Dept. of Biomedical Sciences and Technologies

    2009-04-15

    To characterise tissue sites of immune activation and HIV replication we performed FDG-PET in ART-treated and ART-naive HIV-infected individuals. Specific aims were to establish whether HIV-infected patients can be differentiated on the basis of the detection of specific locations of viral replication, even in the presence of an apparently optimal immunovirological response to ART, and whether these FDG-PET findings can be related to immunovirological variables and AIDS history status. Patients were divided into five groups as follows: subgroup A1 (full responders, n=8): current ART treatment, CD4+ T lymphocytes >500/mL, viral load <50 copies/mL; subgroup A2 (full responders, n=5): same criteria as A-1, but with a previous history of AIDS; subgroup A3 (immunological non responders, n=5): current ART treatment, viral load <50 copies/mL, low CD4+ T lymphocytes (<200/mL); group B (virological non responders, n = 2): current ART treatment, CD4+ T lymphocytes around 500/mL, viral load >50,000 copies/mL; group C (ART-naive, n=5): no current or previous ART treatment, increased viral load. PET images revealed different patterns of FDG uptake. All ART-treated patients with either suppressed (<50 copies/mL; Group A) or high viremia (group B) showed a normal pattern of FDG uptake. On the contrary, the ART-naive subjects with high viraemia (group C) displayed multiple foci of increased glucose metabolism in the lymph nodes. In the ART-naive subjects, FDG uptake, apparently related to viraemia level, was observed in the upper torso mainly in the axillary nodes bilaterally in patients with viraemia below 100,000 copies/mL; in those with viraemia higher than 100,000 copies/mL, FDG uptake was also observed in the inguinal lymph nodes. The emergence, in our study, of a correlation between the percentage of CD8+/CD38+/RO+ T cells (well established markers of progression to AIDS independently of CD4+ T lymphocytes) and positive FDG-PET in ART-naive patients is a novel finding that

  20. Dataset of magnetic resonance images of nonepileptic subjects and temporal lobe epilepsy patients for validation of hippocampal segmentation techniques.

    Science.gov (United States)

    Jafari-Khouzani, Kourosh; Elisevich, Kost V; Patel, Suresh; Soltanian-Zadeh, Hamid

    2011-12-01

    The hippocampus has become the focus of research in several neurodegenerative disorders. Automatic segmentation of this structure from magnetic resonance (MR) imaging scans of the brain facilitates this work. Segmentation techniques must be evaluated using a dataset of MR images with accurate hippocampal outlines generated manually. Manual segmentation is not a trivial task. Lack of a unique segmentation protocol and poor image quality are only two factors that have confounded the consistency required for comparative study. We have developed a publicly available dataset of T1-weighted (T1W) MR images of epileptic and nonepileptic subjects along with their hippocampal outlines to provide a means of evaluation of segmentation techniques. This dataset contains 50 T1W MR images, 40 epileptic and ten nonepileptic. All images were manually segmented by a widely used protocol. Twenty five images were selected for training and were provided with hippocampal labels. Twenty five other images were provided without labels for testing algorithms. The users are allowed to evaluate their generated labels for the test images using 11 segmentation similarity metrics. Using this dataset, we evaluated two segmentation algorithms, Brain Parser and Classifier Fusion and Labeling (CFL), trained by the training set. For Brain Parser, an average Dice coefficient of 0.64 was obtained with the testing set. For CFL, this value was 0.75. Such findings indicate a need for further improvement of segmentation algorithms in order to enhance reliability.

  1. DATASET OF MAGNETIC RESONANCE IMAGES OF NONEPILEPTIC SUBJECTS AND TEMPORAL LOBE EPILEPSY PATIENTS FOR VALIDATION OF HIPPOCAMPAL SEGMENTATION TECHNIQUES

    Science.gov (United States)

    Jafari-Khouzani, Kourosh; Elisevich, Kost V.; Patel, Suresh; Soltanian-Zadeh, Hamid

    2013-01-01

    Summary The hippocampus has become the focus of research in several neurodegenerative disorders. Automatic segmentation of this structure from magnetic resonance (MR) imaging scans of the brain facilitates this work. Segmentation techniques must be evaluated using a dataset of MR images with accurate hippocampal outlines generated manually. Manual segmentation is not a trivial task. Lack of a unique segmentation protocol and poor image quality are only two factors that have confounded the consistency required for comparative study. We have developed a publicly available dataset of T1-weighted (T1W) MR images of epileptic and nonepileptic subjects along with their hippocampal outlines to provide a means of evaluation of segmentation techniques. This dataset contains 50 T1W MR images, 40 epileptic and 10 nonepileptic. All images were manually segmented by a widely used protocol. Twenty five images were selected for training and were provided with hippocampal labels. Twenty five other images were provided without labels for testing algorithms. The users are allowed to evaluate their generated labels for the test images using 11 segmentation similarity metrics. Using this dataset, we evaluated two segmentation algorithms, Brain Parser and Classifier Fusion and Labeling (CFL), trained by the training set. For Brain Parser, an average Dice coefficient of 0.64 was obtained with the testing set. For CFL, this value was 0.75. Such findings indicate a need for further improvement of segmentation algorithms in order to enhance reliability. PMID:21286946

  2. Optimizing visualization in enhanced depth imaging OCT in healthy subjects and patients with retinal pigment epithelial detachment

    Directory of Open Access Journals (Sweden)

    Kampik A

    2012-11-01

    Full Text Available Lukas Reznicek, Efstathios Vounotrypidis, Florian Seidensticker, Karsten Kortuem, Anselm Kampik, Aljoscha S Neubauer, Armin WolfDepartment of Ophthalmology, Ludwig Maximilians University Muenchen, Munich, GermanyBackground: This study’s objective was to optimize the visualization of three different spectral-domain optical coherence tomography (SD-OCT display modalities and evaluate enhanced depth imaging (EDI by comparing the maximum depth of assessment in conventional versus inverted cross-sectional OCT images in healthy subjects and in patients with retinal pigment epithelial detachment (PED.Methods: Cross-sectional SD-OCT conventional and inverted images were obtained with the HRA2 (Heidelberg Retina Angiograph II, Heidelberg Engineering, Heidelberg, Germany. Horizontal as well as vertical sections in three different display modes were blinded for evaluation by three independent, experienced graders for maximal imaging depth of the deep ocular fundus layers.Results: The mean imaging depth as measured from the inner segment/outer segment (IS/OS to the outer choroid of all 14 healthy subjects was 197 ± 44 µm vs 263 ± 56 µm for conventional vs EDI scans: in black/white mode, it was significantly lower (P < 0.001 than in white/black mode (249 ± 42 µm vs 337 ± 71 µm and color/heat mode (254 ± 48 µm vs 354 ± 73 µm. The mean imaging depth of all 14 study eyes with PED was 240 ± 78 µm vs 345 ± 100 µm for conventional vs EDI scans in black/white mode, and was significantly lower (P < 0.001 than in white/black mode (393 ± 104 µm vs 464 ± 126 µm and in color/heat mode (373 ± 106 µm vs 453 ± 114 µm. In each display modality of healthy subjects and of patients with PED, EDI scans showed a significantly higher imaging depth than the corresponding conventional scans.Conclusion: White/black and color/heat modes allow increased imaging depth, compared to black/white mode using both conventional or EDI OCT scans in healthy subjects or

  3. B1 mapping for bias-correction in quantitative T1 imaging of the brain at 3T using standard pulse sequences.

    Science.gov (United States)

    Boudreau, Mathieu; Tardif, Christine L; Stikov, Nikola; Sled, John G; Lee, Wayne; Pike, G Bruce

    2017-12-01

    B1 mapping is important for many quantitative imaging protocols, particularly those that include whole-brain T1 mapping using the variable flip angle (VFA) technique. However, B1 mapping sequences are not typically available on many magnetic resonance imaging (MRI) scanners. The aim of this work was to demonstrate that B1 mapping implemented using standard scanner product pulse sequences can produce B1 (and VFA T1 ) maps comparable in quality and acquisition time to advanced techniques. Six healthy subjects were scanned at 3.0T. An interleaved multislice spin-echo echo planar imaging double-angle (EPI-DA) B1 mapping protocol, using a standard product pulse sequence, was compared to two alternative methods (actual flip angle imaging, AFI, and Bloch-Siegert shift, BS). Single-slice spin-echo DA B1 maps were used as a reference for comparison (Ref. DA). VFA flip angles were scaled using each B1 map prior to fitting T1 ; the nominal flip angle case was also compared. The pooled-subject voxelwise correlation (ρ) for B1 maps (BS/AFI/EPI-DA) relative to the reference B1 scan (Ref. DA) were ρ = 0.92/0.95/0.98. VFA T1 correlations using these maps were ρ = 0.86/0.88/0.96, much better than without B1 correction (ρ = 0.53). The relative error for each B1 map (BS/AFI/EPI-DA/Nominal) had 95(th) percentiles of 5/4/3/13%. Our findings show that B1 mapping implemented using product pulse sequences can provide excellent quality B1 (and VFA T1 ) maps, comparable to other custom techniques. This fast whole-brain measurement (∼2 min) can serve as an excellent alternative for researchers without access to advanced B1 pulse sequences. 1 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2017;46:1673-1682. © 2017 International Society for Magnetic Resonance in Medicine.

  4. Diagnostic implication of magnetic resonance imaging using STIR sequences in optic neuritis

    Energy Technology Data Exchange (ETDEWEB)

    Igarashi, Yasuo; Hashimoto, Masato; Ohyachi, Hiroaki; Nakamura, Yasushi; Ohguro, Hiroshi; Ohtsuka, Kenji; Nakagawa, Takashi (Sapporo Medical Coll. (Japan))

    1994-10-01

    We evaluated 23 patients with optic neuritis by magnetic resonance imaging (MRI) using STIR sequences. The series comprised 5 cases of multiple sclerosis and 18 of unknown etiology. Abnormal high-intensity area was observed in the optic nerve in at least one slice. The slices showing a high signal intensity averaged 3.4 in number. The abnormal finding was most frequent at 15 mm posterior to the eyeglobe in papillitis and retrobulbar optic neuritis. The incidence of abnormal finding was more frequent in papillitis than in retrobulbar neuritis. The high-intensity signal in the optic nerve was not correlated with the latency of major positivity of pattern-reversal VEPs and was rather associated with the clinical course and outcome of optic neuritis. (author).

  5. Deformation analysis of the vocal folds from videostroboscopic image sequences of the larynx.

    Science.gov (United States)

    Saadah, A K; Galatsanos, N P; Bless, D; Ramos, C A

    1998-06-01

    Videostroboscopy is an examination which yields a permanent record of the moving vocal folds. Thus, it allows the diagnosis of abnormalities which contribute to voice disorders. In this paper, in order to find and quantify the deformation of the vocal folds in videostroboscopic recordings, an active contours- (snakes) based approach is used to delineate the vocal folds in each frame of the videostroboscopic image sequence. After this delineation, a new elastic registration algorithm is used to register the vocal fold contours between adjacent frames of the video sequence. This algorithm is based on the regularization principle and is very effective when large deformations are present. A least-squares approach is used to fit an affine model to the displacement vectors found by elastic registration. The parameters of this model, rotation, translation, and deformation along two principle axes, quantify the deformation and allow the succinct characterization of the videostroboscopic recordings based on the deformations that occurred. Experiments are shown with synthetic and real videostroboscopic data that demonstrate the value of the proposed approach.

  6. Improving data availability for brain image biobanking in healthy subjects: Practice-based suggestions from an international multidisciplinary working group.

    Science.gov (United States)

    Shenkin, Susan D; Pernet, Cyril; Nichols, Thomas E; Poline, Jean-Baptiste; Matthews, Paul M; van der Lugt, Aad; Mackay, Clare; Lanyon, Linda; Mazoyer, Bernard; Boardman, James P; Thompson, Paul M; Fox, Nick; Marcus, Daniel S; Sheikh, Aziz; Cox, Simon R; Anblagan, Devasuda; Job, Dominic E; Dickie, David Alexander; Rodriguez, David; Wardlaw, Joanna M

    2017-06-01

    Brain imaging is now ubiquitous in clinical practice and research. The case for bringing together large amounts of image data from well-characterised healthy subjects and those with a range of common brain diseases across the life course is now compelling. This report follows a meeting of international experts from multiple disciplines, all interested in brain image biobanking. The meeting included neuroimaging experts (clinical and non-clinical), computer scientists, epidemiologists, clinicians, ethicists, and lawyers involved in creating brain image banks. The meeting followed a structured format to discuss current and emerging brain image banks; applications such as atlases; conceptual and statistical problems (e.g. defining 'normality'); legal, ethical and technological issues (e.g. consents, potential for data linkage, data security, harmonisation, data storage and enabling of research data sharing). We summarise the lessons learned from the experiences of a wide range of individual image banks, and provide practical recommendations to enhance creation, use and reuse of neuroimaging data. Our aim is to maximise the benefit of the image data, provided voluntarily by research participants and funded by many organisations, for human health. Our ultimate vision is of a federated network of brain image biobanks accessible for large studies of brain structure and function. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Time-sequenced and spectrally filtered Rayleigh imaging of shock wave and boundary layer structure for inlet characterization

    Science.gov (United States)

    Forkey, Joseph; Cogne, Sandrine; Smits, Alexander; Bogdonoff, Seymour; Lempert, Walter R.; Miles, Richard B.

    1993-01-01

    Multiple pulsed Rayleigh imaging and filtered Rayleigh scattering are used to generate images of a complex boundary layer structure, shock wave/boundary layer interactions, and crossing shock waves. Time-sequenced Rayleigh images taken with a visible, double-pulsed laser system show the evolution of boundary layer structure of the internal flow in a generic cross-shock inlet. The images taken in the inlet give insight into 3D effects caused by the inlet geometry and may be used for modeling the complex flows.

  8. Is subjective perception of negative body image among adolescents associated with bullying?

    NARCIS (Netherlands)

    Holubcikova, Jana; Kolarcik, Peter; Geckova, Andrea Madarasova; Van Dijk, Jitse P.; Reijneveld, Sijmen A.

    Adolescents' body image dissatisfaction has an adverse effect on peer relationships. It may lead to changes in behaviour (aggressive or passive) and consequently to bullying behaviour. Our aim was to assess the association between body image dissatisfaction and involvement in bullying and whether

  9. Using a contrast-enhanced imaging sequence at 3-minute delay in 3-T magnetic resonance imaging for acute infarct evaluation.

    Science.gov (United States)

    Comte, Alexandre; Kastler, Bruno; Laborie, Laurent; Hadjidekov, Georges; Meneveau, Nicolas; Boulahdour, Hatem

    2008-09-01

    To investigate the performance of a delayed-enhancement (DE) sequence adapted for a 3-minute delay after bolus injection of a contrast media in cardiac magnetic resonance imaging (MRI) in acute reperfused myocardial infarction. Sixty-three patients with recent myocardial infarction underwent contrast-enhanced MRI. Sequences of first-pass (FP) perfusion imaging and DE imaging at 3 and 15 minutes were performed at the acute phase. Of these patients, 49 had a follow-up cardiac magnetic resonance examination. Infarct sizes were quantified by 2 experienced users with a 17-segment model at the acute phase (at FP and at 3- and 15-minute delay) and at the chronic phase (at 15 minutes because only fibrous areas hyperenhance late). Areas of hypoenhancement and hyperenhancement were also calculated. Results from the 3-minute imaging sequence at the acute phase were compared with the FP (taking into account dark signal areas), with the 15-minute DE imaging sequence results at the acute phase [taking into account dark signal and hyperenhanced (white plus dark signal) areas] and with the 15-minute DE imaging sequence from the chronic phase (taking into account hyperenhanced areas). Least squares regression and Bland-Altman plots were performed for the comparisons. For the evaluation of hyperenhancement, the comparison between imaging sequence results at 3 minutes versus 15-minute DE at the acute phase (respectively, at the chronic phase) shows a good correlation (r(2) = 0.941; respectively r(2) = 0.862, at the chronic phase) and the Bland-Altman plot indicates a good concordance (m =-0.43; SD = 2.69; respectively m = 2.76; SD = 3.92); For the evaluation of hypoenhancement, the comparison between imaging sequence results at 3 minutes versus FP (respectively, 15 minutes at the acute phase) also shows a good correlation (r(2) = 0.751; respectively r(2) = 0.71) and the Bland-Altman plot indicates a good concordance (m = -1.06; SD = 3.34; respectively m = 2.90; SD = 3.11). Finally

  10. 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.

  11. High-Throughput Sequencing of Viable Microbial Communities in Raw Pork Subjected to a Fast Cooling Process.

    Science.gov (United States)

    Yang, Chao; Che, You; Qi, Yan; Liang, Peixin; Song, Cunjiang

    2017-01-01

    This study aimed to investigate the effect of the fast cooling process on the microbiological community in chilled fresh pork during storage. We established a culture-independent method to study viable microbes in raw pork. Tray-packaged fresh pork and chilled fresh pork were completely spoiled after 18 and 49 d in aseptic bags at 4 °C, respectively. 16S/18S ribosomal RNAs were reverse transcribed to cDNA to characterize the activity of viable bacteria/fungi in the 2 types of pork. Both cDNA and total DNA were analyzed by high-throughput sequencing, which revealed that viable Bacteroides sp. were the most active genus in rotten pork, although viable Myroides sp. and Pseudomonas sp. were also active. Moreover, viable fungi were only detected in chilled fresh pork. The sequencing results revealed that the fast cooling process could suppress the growth of microbes present initially in the raw meat to extend its shelf life. Our results also suggested that fungi associated with pork spoilage could not grow well in aseptic tray-packaged conditions. © 2016 Institute of Food Technologists®.

  12. High-Sequence Diversity and Rapid Virus Turnover Contribute to Higher Rates of Coreceptor Switching in Treatment-Experienced Subjects with HIV-1 Viremia.

    Science.gov (United States)

    Nedellec, Rebecca; Herbeck, Joshua T; Hunt, Peter W; Deeks, Steven G; Mullins, James I; Anton, Elizabeth D; Reeves, Jacqueline D; Mosier, Donald E

    2017-03-01

    Coreceptor switching from CCR5 to CXCR4 is common during chronic HIV-1 infection, but is even more common in individuals who have failed antiretroviral therapy (ART). Prior studies have suggested rapid mutation and/or recombination of HIV-1 envelope (env) genes during coreceptor switching. We compared the functional and genotypic changes in env of viruses from viremic subjects who had failed ART just before and after coreceptor switching and compared those to viruses from matched subjects without coreceptor switching. Analysis of multiple unique functional env clones from each subject revealed extensive diversity at both sample time points and rapid diversification of sequences during the 4-month interval in viruses from both 9 subjects with coreceptor switching and 15 control subjects. Only two subjects had envs with evidence of recombination. Three findings distinguished env clones from subjects with coreceptor switching from controls: (1) lower entry efficiency via CCR5; (2) longer V1/V2 regions; and (3), lower nadir CD4 T cell counts during prior years of infection. Most of these subjects harbored virus with lower replicative capacity associated with protease (PR) and/or reverse transcriptase inhibitor resistance mutations, and the extensive diversification tended to lead either to improved entry efficiency via CCR5 or the gain of entry function via CXCR4. These results suggest that R5X4 or X4 variants emerge from a diverse, low-fitness landscape shaped by chronic infection, multiple ART resistance mutations, the availability of target cells, and reduced entry efficiency via CCR5.

  13. Optimization of multi-pulse sequences for nonlinear contrast agent imaging using a cMUT array.

    Science.gov (United States)

    Novell, Anthony; Arena, Christopher B; Kasoji, Sandeep; Dayton, Paul A

    2015-04-21

    Capacitive micromachined ultrasonic transducer (cMUT) technology provides advantages such as wide frequency bandwidth, which can be exploited for contrast agent imaging. Nevertheless, the efficiency of traditional multi-pulse imaging schemes, such as pulse inversion (PI), remains limited because of the intrinsic nonlinear character of cMUTs. Recently, a new contrast imaging sequence, called bias voltage modulation sequence (BVM), has been specifically developed for cMUTs to suppress their unwanted nonlinear behavior. In this study, we propose to optimize contrast agent detection by combining the BVM sequence with PI and/or chirp reversal (CR). An aqueous dispersion of lipid encapsulated microbubbles was exposed to several combinations of multi-pulse imaging sequences. Approaches were evaluated in vitro using 9 inter-connected elements of a cMUT linear array (excitation frequency of 4 MHz; peak negative pressure of 100 kPa). For sequences using chirp excitations, a specific compression filter was designed to compress and extract several nonlinear components from the received microbubble responses. A satisfactory cancellation of the nonlinear signal from the source is achieved when BVM is combined with PI and CR. In comparison with PI and CR imaging modes alone, using sequences incorporating BVM increases the contrast-to-tissue ratio by 10.0 dB and 4.6 dB, respectively. Furthermore, the combination of BVM with CR and PI results in a significant increase of the contrast-to-noise ratio (+29 dB). This enhancement is attributed to the use of chirps as excitation signals and the improved preservation of several nonlinear components contained within the contrast agent response.

  14. Subjective cognition and amyloid deposition imaging: a Pittsburgh Compound B positron emission tomography study in normal elderly individuals

    Science.gov (United States)

    Perrotin, Audrey; Mormino, Elizabeth C.; Madison, Cindee M.; Hayenga, Amynta O.; Jagust, William J.

    2012-01-01

    Background Subjective cognitive impairment (SCI) as an early clinical manifestation in Alzheimer disease (AD) is a central and highly debated question. Objective To study the relationship between subjective cognition and the neuropathological hallmark of AD, amyloid-beta (Aβ) deposition, imaged with [11C]-Pittsburg compound B (PiB) - positron emission tomography (PET), in normal elderly individuals. Design Cross-sectional analysis. Subjects Forty-eight cognitively normal elderly subjects (11 with high PiB uptake and 28 with low PiB uptake) were included. All underwent clinical and neuropsychological evaluations and MRI and PET scanning. Results High PiB subjects showed significantly lower performance than low PiB subjects on an episodic memory measure, and were less confident about their general memory abilities when required to evaluate themselves relative to other people of the same age. High and low PiB groups did not differ on the accuracy of their cognitive self-reports compare to objective cognitive performance. General memory self-reports from the whole group were significantly correlated to regional PiB uptake in the right medial prefrontal cortex (PFC)/anterior cingulate cortex (ACC) and in the right precuneus/posterior cingulate cortex (PCC). Reduced confidence about memory abilities was associated with greater PiB in these brain regions. All results are independent of demographic variables and depressive affects. Conclusions Our findings suggest that a decrease of self-confidence about memory abilities in cognitively normal elderly subjects is related to the neuropathological hallmark of AD measured with PiB-PET imaging. The relevance of SCI in the early stages of the AD pathological process is addressed. PMID:22332189

  15. Automated method for tracing leading and trailing processes of migrating neurons in confocal image sequences

    Science.gov (United States)

    Kerekes, Ryan A.; Gleason, Shaun S.; Trivedi, Niraj; Solecki, David J.

    2010-03-01

    Segmentation, tracking, and tracing of neurons in video imagery are important steps in many neuronal migration studies and can be inaccurate and time-consuming when performed manually. In this paper, we present an automated method for tracing the leading and trailing processes of migrating neurons in time-lapse image stacks acquired with a confocal fluorescence microscope. In our approach, we first locate and track the soma of the cell of interest by smoothing each frame and tracking the local maxima through the sequence. We then trace the leading process in each frame by starting at the center of the soma and stepping repeatedly in the most likely direction of the leading process. This direction is found at each step by examining second derivatives of fluorescent intensity along curves of constant radius around the current point. Tracing terminates after a fixed number of steps or when fluorescent intensity drops below a fixed threshold. We evolve the resulting trace to form an improved trace that more closely follows the approximate centerline of the leading process. We apply a similar algorithm to the trailing process of the cell by starting the trace in the opposite direction. We demonstrate our algorithm on two time-lapse confocal video sequences of migrating cerebellar granule neurons (CGNs). We show that the automated traces closely approximate ground truth traces to within 1 or 2 pixels on average. Additionally, we compute line intensity profiles of fluorescence along the automated traces and quantitatively demonstrate their similarity to manually generated profiles in terms of fluorescence peak locations.

  16. Compared with the Conventional MR Imaging, Do the Constructive Interference Steady State Sequence and Diffusion Weighted Imaging Aid in the Diagnosis of Lumbar Disc Hernias?

    Science.gov (United States)

    Aydin, Hasan; Kizilgoz, Volkan; Hekimoglu, Baki

    2011-12-01

    Our aim was to evaluate the efficacy of Diffusion Weighted Imaging (DWI) and Constructive Interference Steady State (CISS) sequences in the depiction of lumbar disc hernias, including sequestrated and extruded discs. 100 patients; 35 males and 65 females, with 3 sequestration-16 extruded and 81 protruded all together 100 herniated discs were involved in this study. If a patient had more than one herniated disc, then the more precise herniation was included. All the MRI procedures were handled in Siemens Symphony Power 1.5 T. magnet. DWI- Apparent diffusion coefficient (ADC mapping) and CISS sequences were obtained in axial planes. Statistical analysis of CISS and DWI results were analysed by fischer's test, chi square statistics. CISS sequence had a 89% sensitivity, 100% specificity for all lumbar disc hernias, had 100% sensitivity and specificity in the evaluation of sequestrated and extruded discs. DWI had a 77% sensitivity and %100 specificity, had 100% sensitivity and 50% specificity in the evaluation of extrusion, 100% sensitivity and specificity in the evaluation of sequestration. CISS sequence and quantitative DWI may be alternative imaging modalities to the routine MR imaging sequences in the depiction of lumbar disc hernias, including sequestration and extruded discs.

  17. Inaccuracy of age assessment from images of postpubescent subjects in cases of alleged child pornography.

    Science.gov (United States)

    Rosenbloom, Arlan L

    2013-03-01

    Despite frequent medical expert testimony authoritatively stating that images of individuals who are postpubescent indicate age less than 18 and therefore, child pornography, developmental experts have noted that a scientific basis for such estimation is lacking. In fact, recent studies have demonstrated a high degree of inaccuracy in such estimates, and that the stage of breast development often used as indicative of age under 18 years is present in a substantial percentage of adult women. Ten images of adult women from legitimate pornographic sites promoting youthful images were shown to 16 pediatric endocrinologists expert in evaluating maturation, who determined whether or not the individuals represented were under 18 years of age. They also provided information about what features were most important in their evaluations. Sixty-nine percent of the 160 estimates were that the images represented females under 18 years of age. There was wide variability in the designation of importance of the various features of maturation in reaching conclusions, with breast development and facial appearance considered most important. This study confirms that medical testimony, even by experts in adolescent development, can deem images of adult women selected for their youthful appearance to be under age 18 two thirds of the time. Thus, important as prosecuting users of child pornographic material may be, justice requires the avoidance of testimony that is not scientifically based.

  18. 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...

  19. Image size invariant visual cryptography for general access structures subject to display quality constraints.

    Science.gov (United States)

    Lee, Kai-Hui; Chiu, Pei-Ling

    2013-10-01

    Conventional visual cryptography (VC) suffers from a pixel-expansion problem, or an uncontrollable display quality problem for recovered images, and lacks a general approach to construct visual secret sharing schemes for general access structures. We propose a general and systematic approach to address these issues without sophisticated codebook design. This approach can be used for binary secret images in non-computer-aided decryption environments. To avoid pixel expansion, we design a set of column vectors to encrypt secret pixels rather than using the conventional VC-based approach. We begin by formulating a mathematic model for the VC construction problem to find the column vectors for the optimal VC construction, after which we develop a simulated-annealing-based algorithm to solve the problem. The experimental results show that the display quality of the recovered image is superior to that of previous papers.

  20. Effect of inspiration on airway dimensions measured in maximal inspiration CT images of subjects without airflow limitation

    Energy Technology Data Exchange (ETDEWEB)

    Petersen, Jens; Raket, Lars Lau; Nielsen, Mads [University of Copenhagen, Department of Computer Science, Copenhagen (Denmark); Wille, Mathilde M.W.; Dirksen, Asger [University of Copenhagen, Department of Respiratory Medicine, Gentofte Hospital, Hellerup (Denmark); Feragen, Aasa [University of Copenhagen, Department of Computer Science, Copenhagen (Denmark); Max Planck Institute for Intelligent Systems and Max Planck Institute for Developmental Biology, Tuebingen (Germany); Pedersen, Jesper H. [Rigshospitalet, University Hospital of Copenhagen, Department of Cardio-Thoracic Surgery RT, Copenhagen (Denmark); Bruijne, Marleen de [University of Copenhagen, Department of Computer Science, Copenhagen (Denmark); Erasmus MC Rotterdam, Departments of Medical Informatics and Radiology, Rotterdam (Netherlands)

    2014-09-15

    To study the effect of inspiration on airway dimensions measured in voluntary inspiration breath-hold examinations. 961 subjects with normal spirometry were selected from the Danish Lung Cancer Screening Trial. Subjects were examined annually for five years with low-dose CT. Automated software was utilized to segment lungs and airways, identify segmental bronchi, and match airway branches in all images of the same subject. Inspiration level was defined as segmented total lung volume (TLV) divided by predicted total lung capacity (pTLC). Mixed-effects models were used to predict relative change in lumen diameter (ALD) and wall thickness (AWT) in airways of generation 0 (trachea) to 7 and segmental bronchi (R1-R10 and L1-L10) from relative changes in inspiration level. Relative changes in ALD were related to relative changes in TLV/pTLC, and this distensibility increased with generation (p < 0.001). Relative changes in AWT were inversely related to relative changes in TLV/pTLC in generation 3-7 (p < 0.001). Segmental bronchi were widely dispersed in terms of ALD (5.7 ± 0.7 mm), AWT (0.86 ± 0.07 mm), and distensibility (23.5 ± 7.7 %). Subjects who inspire more deeply prior to imaging have larger ALD and smaller AWT. This effect is more pronounced in higher-generation airways. Therefore, adjustment of inspiration level is necessary to accurately assess airway dimensions. (orig.)

  1. Registration-based assessment of regional lung function via volumetric CT images of normal subjects vs. severe asthmatics

    Science.gov (United States)

    Choi, Sanghun; Hoffman, Eric A.; Wenzel, Sally E.; Tawhai, Merryn H.; Yin, Youbing; Castro, Mario

    2013-01-01

    The purpose of this work was to explore the use of image registration-derived variables associated with computed tomographic (CT) imaging of the lung acquired at multiple volumes. As an evaluation of the utility of such an imaging approach, we explored two groups at the extremes of population ranging from normal subjects to severe asthmatics. A mass-preserving image registration technique was employed to match CT images at total lung capacity (TLC) and functional residual capacity (FRC) for assessment of regional air volume change and lung deformation between the two states. Fourteen normal subjects and thirty severe asthmatics were analyzed via image registration-derived metrics together with their pulmonary function test (PFT) and CT-based air-trapping. Relative to the normal group, the severely asthmatic group demonstrated reduced air volume change (consistent with air trapping) and more isotropic deformation in the basal lung regions while demonstrating increased air volume change associated with increased anisotropic deformation in the apical lung regions. These differences were found despite the fact that both PFT-derived TLC and FRC in the two groups were nearly 100% of predicted values. Data suggest that reduced basal-lung air volume change in severe asthmatics was compensated by increased apical-lung air volume change and that relative increase in apical-lung air volume change in severe asthmatics was accompanied by enhanced anisotropic deformation. These data suggest that CT-based deformation, assessed via inspiration vs. expiration scans, provides a tool for distinguishing differences in lung mechanics when applied to the extreme ends of a population range. PMID:23743399

  2. 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.

  3. Integrated Georeferencing of Stereo Image Sequences Captured with a Stereovision Mobile Mapping System - Approaches and Practical Results

    Science.gov (United States)

    Eugster, H.; Huber, F.; Nebiker, S.; Gisi, A.

    2012-07-01

    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.

  4. Effect of Subliminal Lexical Priming on the Subjective Perception of Images: A Machine Learning Approach.

    Science.gov (United States)

    Mohan, Dhanya Menoth; Kumar, Parmod; Mahmood, Faisal; Wong, Kian Foong; Agrawal, Abhishek; Elgendi, Mohamed; Shukla, Rohit; Ang, Natania; Ching, April; Dauwels, Justin; Chan, Alice H D

    2016-01-01

    The purpose of the study is to examine the effect of subliminal priming in terms of the perception of images influenced by words with positive, negative, and neutral emotional content, through electroencephalograms (EEGs). Participants were instructed to rate how much they like the stimuli images, on a 7-point Likert scale, after being subliminally exposed to masked lexical prime words that exhibit positive, negative, and neutral connotations with respect to the images. Simultaneously, the EEGs were recorded. Statistical tests such as repeated measures ANOVAs and two-tailed paired-samples t-tests were performed to measure significant differences in the likability ratings among the three prime affect types; the results showed a strong shift in the likeness judgment for the images in the positively primed condition compared to the other two. The acquired EEGs were examined to assess the difference in brain activity associated with the three different conditions. The consistent results obtained confirmed the overall priming effect on participants' explicit ratings. In addition, machine learning algorithms such as support vector machines (SVMs), and AdaBoost classifiers were applied to infer the prime affect type from the ERPs. The highest classification rates of 95.0% and 70.0% obtained respectively for average-trial binary classifier and average-trial multi-class further emphasize that the ERPs encode information about the different kinds of primes.

  5. Automated quantification of three-dimensional subject motion to monitor image quality in high-resolution peripheral quantitative computed tomography

    Science.gov (United States)

    Pauchard, Yves; Ayres, Fábio J.; Boyd, Steven K.

    2011-10-01

    Subject motion during acquisition of high-resolution peripheral quantitative computed tomography (HR-pQCT) results in image artifacts and interferes with quantification of bone architecture used to study bone-related diseases such as osteoporosis. We propose an automatic method to measure physical subject motion that frequently takes place during acquisition. Three measures derived from projection data are proposed to quantify motion artifacts: in-plane translation (εT) and in-plane rotation (εR) utilizing projection moments and longitudinal translation (εz) based on tracking projection profiles. Validation was performed using a phantom containing sections of distal human cadaver radii attached to a mechanical device to precisely control in-plane rotation and longitudinal translation that was intentionally performed during HR-pQCT data acquisition. Motion measured by the new automated technique was compared to the known applied motion, and related to percent errors in morphological parameters quantifying bone properties. It was determined that of the three proposed measures, εT best captured a quantified representation of image quality. εT linearly relates to true physical in-plane translational motion (r2 = 0.95, pmovements and combines well with εT to fully characterize physical motion artifacts. The magnitude of εT corresponds to morphological parameter error and is an excellent basis to select high-quality images. Morphological parameter errors from these experiments confirmed our earlier computer simulations which showed that increased subject motion resulted in artificially higher trabecular number, and artificially lower bone mineral density and cortical thickness. The magnitude and, notably, the uncertainty of the morphological errors increased with increased physical motion, and this impedes a direct linear compensation of parameter errors. The automated method presented provides a basis for consistent and objective quality assurance for HR

  6. Bienestar subjetivo e imagen corporal en estudiantes universitarias de Arequipa/ Subjective wellbeing and body image in college students in Arequipa

    Directory of Open Access Journals (Sweden)

    Andrea Prieto Vela

    2015-12-01

    Full Text Available RESUMEN Este estudio exploró la correlación entre el bienestar subjetivo y la imagen corporal de las estudiantes mujeres en una universidad de Arequipa. La muestra estuvo constituida de 155 estudiantes mujeres entre los 17 y 24 años de las tres carreras profesionales. Las participantes fueron evaluadas en sus respectivos salones. La validación del Cuestionario de la Imagen Corporal (BSQ fue calculada con Alfa de Cronbach y se obtuvo un valor de 0.92. Los resultados indicaron que existe una correlación negativa significativa entre el bienestar subjetivo y la imagen corporal (r = -0.478; p 0.05 y a la imagen corporal (t = -0.606; p > 0.05. Esto muestra que la distorsión de la imagen corporal tiene un impacto negativo en el bienestar subjetivo de las estudiantes universitarias mujeres. ABSTRACT This study explored the correlation between subjective wellbeing and body image of female students at a university in Arequipa. The sample consisted by 155 female students between 17 and 24 years old from the three professional careers. The participants were evaluated in their respective classrooms. The validation of the Body Shape Questionnaire (BSQ was calculated using Cronbach’s alpha and obtained a value of 0.92. The results indicated that there is significant negative correlation between the subjective wellbeing and body image (r = -0.478; p 0.05 and body image (t = -0.606; p > 0.05. This shows that the distortion of body image has a negative impact on the subjective wellbeing of women university students.

  7. Comparison of breath-hold T1-weighted MR sequences for imaging of the liver.

    Science.gov (United States)

    Semelka, R C; Willms, A B; Brown, M A; Brown, E D; Finn, J P

    1994-01-01

    Three rapid T1-weighted gradient-echo techniques for imaging of the liver were compared: fast low-angle shot (FLASH) and section-selective (SSTF) and non-section-selective (NSTF) inversion-recovery TurboFLASH. Ten healthy volunteers were imaged at 1.5 T, with breath-hold images acquired in the transaxial and coronal planes and non-breath-hold images in the transaxial plane. Breath-hold images were evaluated quantitatively and qualitatively, and non-breath-hold images were evaluated qualitatively. FLASH images had significantly higher (P FLASH images than on NSTF and SSTF images. With breath hold, FLASH images were rated as having the highest quality in the axial plane, followed by NSTF and SSTF images. In the coronal plane, NSTF images were rated as having the highest quality. For images acquired during patient respiration, NSTF images had the highest quality and showed the least degradation. The results suggest that FLASH images have the highest SD/N and S/N for liver imaging and have the highest quality in the axial plane. In patients who cannot suspend respiration. NSTF images may be least affected by breathing artifact and provide reasonable image quality.

  8. Image quality analysis of high-density diffuse optical tomography incorporating a subject-specific head model

    Directory of Open Access Journals (Sweden)

    Yuxuan eZhan

    2012-05-01

    Full Text Available High-density diffuse optical tomography (HD-DOT methods have shown significant improvement in localization accuracy and image resolution compared to traditional topographic near infrared spectroscopy (NIRS of the human brain. In this work we provide a comprehensive evaluation of image quality in visual cortex mapping via a simulation study with the use of an anatomical head model derived from MRI data of a human subject. A model of individual head anatomy provides the surface shape and internal structure that allow for the construction of a more realistic physical model for the forward problem, as well as the use of a structural constraint in the inverse problem. The HD-DOT model utilized here incorporates multiple source-detector separations with continuous-wave data with added noise based on experimental results. To evaluate image quality we quantify the localization error and localized volume at half maximum (LVHM throughout a region of interest (ROI within the visual cortex and systematically analyze the use of whole brain tissue spatial constraint within image reconstruction. Our results demonstrate that an image quality with less than 10 mm in localization error and 1000 m3 in LVHM can be obtained up to 13 mm below the scalp surface with a typical unconstrained reconstruction and up to 18 mm deep when a spatial constraint based on the brain tissue is utilized.

  9. Subjective evaluations of mammographic accreditation phantom images by three observer groups.

    Science.gov (United States)

    Brooks, K W; Trueblood, J H; Kearfott, K J

    1994-01-01

    Mammography providers are under increasing pressure to become certified by the American College of Radiology (ACR). Successful accreditation is contingent on passing a phantom image quality test. This study was undertaken to evaluate viewer performance with the phantom image evaluation process and to determine any observer group differences. A series of standard phantom images were viewed by 30 medical physicists, 30 diagnostic radiologists, and 30 inexperienced observers. From the responses, object detection rates and passing rates according to the ACR criteria were established. These responses were analyzed with standard nonparametric tests to assess the degree of variability, correlation, and agreement among different observer groups. Median passing scores were similar for the radiologists and untrained readers, but the medical physicists appear to differ from the other two groups. There was not sufficient evidence to indicate that special training among physicists made a significant difference in median passing scores or mass detection rates. However, such training appeared to significantly affect the detection of microcalcification and fibril test patterns among the physicists' subgroups. Agreement among observer groups was high for all groups, but tended to be lower for overall passing rates than for any of the individual test objects. Agreement among physicists was affected by their subspecialty, presumably caused by their levels of specific training for these visual tasks. The authors conclude that choosing medical physicists to evaluate mammographic phantom films appears to be a good choice among potential observer groups, and that special training for reading these images affects their detection abilities and consistency. However, because passing rates did not appear to be affected by special training and given the current rapid degree of change in this area, more testing of medical physicists is desirable to examine these effects over time, and to study

  10. Investigating the Neural Bases for Intra-Subject Cognitive Efficiency Using Functional Magnetic Resonance Imaging

    Directory of Open Access Journals (Sweden)

    Neena K. Rao

    2014-10-01

    Full Text Available Several fMRI studies have examined brain regions mediating inter-subject variability in cognitive efficiency, but none have examined regions mediating intra-subject variability in efficiency. Thus, the present study was designed to identify brain regions involved in intra-subject variability in cognitive efficiency via participant-level correlations between trial-level reaction time (RT and trial-level fMRI BOLD percent signal change on a processing speed task. On each trial, participants indicated whether a digit-symbol probe-pair was present or absent in an array of nine digit-symbol probe-pairs while fMRI data were collected. Deconvolution analyses, using RT time-series models (derived from the proportional scaling of an event-related hemodynamic response function model by trial-level RT, were used to evaluate relationships between trial-level RTs and BOLD percent signal change. Although task-related patterns of activation and deactivation were observed in regions including bilateral occipital, bilateral parietal, portions of the medial wall such as the precuneus, default mode network regions including anterior cingulate, posterior cingulate, bilateral temporal, right cerebellum, and right cuneus, RT-BOLD correlations were observed in a more circumscribed set of regions. Positive RT-related patterns, or RT-BOLD correlations where fast RTs were associated with lower BOLD percent signal change, were observed in regions including bilateral occipital, bilateral parietal, and the precuneus. RT-BOLD correlations were not observed in the default mode network indicating a smaller set of regions associated with intra-subject variability in cognitive efficiency. The results are discussed in terms of a distributed area of regions that mediate variability in the cognitive efficiency that might underlie processing speed differences between individuals.

  11. The facial expression of schizophrenic patients applied with infrared thermal facial image sequence.

    Science.gov (United States)

    Jian, Bo-Lin; Chen, Chieh-Li; Chu, Wen-Lin; Huang, Min-Wei

    2017-06-24

    Schizophrenia is a neurological disease characterized by alterations to patients' cognitive functions and emotional expressions. Relevant studies often use magnetic resonance imaging (MRI) of the brain to explore structural differences and responsiveness within brain regions. However, as this technique is expensive and commonly induces claustrophobia, it is frequently refused by patients. Thus, this study used non-contact infrared thermal facial images (ITFIs) to analyze facial temperature changes evoked by different emotions in moderately and markedly ill schizophrenia patients. Schizophrenia is an emotion-related disorder, and images eliciting different types of emotions were selected from the international affective picture system (IAPS) and presented to subjects during ITFI collection. ITFIs were aligned using affine registration, and the changes induced by small irregular head movements were corrected. The average temperatures from the forehead, nose, mouth, left cheek, and right cheek were calculated, and continuous temperature changes were used as features. After performing dimensionality reduction and noise removal using the component analysis method, multivariate analysis of variance and the Support Vector Machine (SVM) classification algorithm were used to identify moderately and markedly ill schizophrenia patients. Analysis of five facial areas indicated significant temperature changes in the forehead and nose upon exposure to various emotional stimuli and in the right cheek upon evocation of high valence low arousal (HVLA) stimuli. The most significant P-value (lower than 0.001) was obtained in the forehead area upon evocation of disgust. Finally, when the features of forehead temperature changes in response to low valence high arousal (LVHA) were reduced to 9 using dimensionality reduction and noise removal, the identification rate was as high as 94.3%. Our results show that features obtained in the forehead, nose, and right cheek significantly

  12. Imaging sequences for intraoperative MR-guided laparoscopic liver resection in 1.0-T high field open MRI

    Energy Technology Data Exchange (ETDEWEB)

    Chopra, S.S.; Schmidt, S.C.; Schumacher, G. [University Medicine Berlin, Department of General, Visceral and Transplantation Surgery, Charite Campus Virchow Clinic, Berlin (Germany); Rump, J.; Streitparth, F.; Teichgraeber, U. [University Medicine Berlin, Department of Radiology, Charite Campus Mitte, Berlin (Germany); Seebauer, C. [University Medicine Berlin, Department of Trauma Surgery, Charite Campus Virchow Clinic, Berlin (Germany); Voort, I.V. der [University Medicine Berlin, Department of Gastroenterology, Charite Campus Virchow Clinic, Berlin (Germany)

    2009-09-15

    The aim of this study was to identify suitable interactive (dynamic) magnetic resonance (MR) sequences for real-time MR-guided liver dissection in a 1.0-T high field open MRI system. Four dynamic sequences encompassing balanced steady state free precession (bSSFP), T1W gradient echo (GRE), T2W GRE and T2W fast spin echo (FSE) were analysed regarding the image quality, artefact susceptibility and the performance of SNR and CNR. The T2W FSE sequence (1.5 s/image) was considered superior because of an intraoperative SNR of 6.9 ({+-}0.7) and CNR (vessel to parenchyma) of 5.6 ({+-}1.7) in the interventional setting. As a proof of concept, MR-guided laparoscopic liver resection was performed in two healthy domestic pigs by using the T2W FSE sequence. The additional MR images offered simultaneous multiplanar real-time visualisation of the liver vessels during the intervention and thereby increased the anatomical orientation of the surgeon. (orig.)

  13. In search of Leonardo: computer-based facial image analysis of Renaissance artworks for identifying Leonardo as subject

    Science.gov (United States)

    Tyler, Christopher W.; Smith, William A. P.; Stork, David G.

    2012-03-01

    One of the enduring mysteries in the history of the Renaissance is the adult appearance of the archetypical "Renaissance Man," Leonardo da Vinci. His only acknowledged self-portrait is from an advanced age, and various candidate images of younger men are difficult to assess given the absence of documentary evidence. One clue about Leonardo's appearance comes from the remark of the contemporary historian, Vasari, that the sculpture of David by Leonardo's master, Andrea del Verrocchio, was based on the appearance of Leonardo when he was an apprentice. Taking a cue from this statement, we suggest that the more mature sculpture of St. Thomas, also by Verrocchio, might also have been a portrait of Leonardo. We tested the possibility Leonardo was the subject for Verrocchio's sculpture by a novel computational technique for the comparison of three-dimensional facial configurations. Based on quantitative measures of similarities, we also assess whether another pair of candidate two-dimensional images are plausibly attributable as being portraits of Leonardo as a young adult. Our results are consistent with the claim Leonardo is indeed the subject in these works, but we need comparisons with images in a larger corpora of candidate artworks before our results achieve statistical significance.

  14. Ultrasound imaging of the diagonal dimension of the deep cervical flexor muscles: A reliability study on healthy subjects.

    Science.gov (United States)

    Ishida, Hiroshi; Suehiro, Tadanobu; Kurozumi, Chiharu; Ono, Koji; Watanabe, Susumu

    2015-07-01

    The purpose of this study is to assess the reliability of a new ultrasound imaging (USI) parameter and procedure for the evaluation of the size of the deep cervical flexor (DCF) muscles. Thirty-one healthy male subjects (21.6 ± 2.5 years old) participated in this study. Two images of the diagonal dimension (DD) of the DCF of the subjects, at 1.5 fingerbreadths below the laryngeal prominence of the thyroid cartilage in a relaxed state, were taken on separate days with a 1-week interval. The intraclass correlation coefficient between the days was 0.82 (95% confidence interval, 0.65-0.91). The standard error of measurement and minimal detectable change were 0.8 mm and 2.1 mm, respectively. The results indicated that the DD may be used as a reliable USI parameter to measure the DCF thickness in healthy subjects. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. 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

  16. 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).

  17. A New Positron Emission Tomography (PET) Radioligand for Imaging Sigma-1 Receptors in Living Subjects

    DEFF Research Database (Denmark)

    James, Michelle L; Shen, Bin; Zavaleta, Cristina L

    2012-01-01

    Sigma-1 receptor (S1R) radioligands have the potential to detect and monitor various neurological diseases. Herein we report the synthesis, radiofluorination and evaluation of a new S1R ligand 6-(3-fluoropropyl)-3-(2-(azepan-1-yl)ethyl)benzo[d]thiazol-2(3H)-one ([(18)F]FTC-146, [(18)F]13). [(18)F....... These results indicate that [(18)F]13 is a promising candidate radiotracer for further evaluation as a tool for studying S1Rs in living subjects....

  18. Validation of the Dominant Sequence Paradigm and Role of Dynamic Contrast-enhanced Imaging in PI-RADS Version 2.

    Science.gov (United States)

    Greer, Matthew D; Shih, Joanna H; Lay, Nathan; Barrett, Tristan; Kayat Bittencourt, Leonardo; Borofsky, Samuel; Kabakus, Ismail M; Law, Yan Mee; Marko, Jamie; Shebel, Haytham; Mertan, Francesca V; Merino, Maria J; Wood, Bradford J; Pinto, Peter A; Summers, Ronald M; Choyke, Peter L; Turkbey, Baris

    2017-12-01

    Purpose To validate the dominant pulse sequence paradigm and limited role of dynamic contrast material-enhanced magnetic resonance (MR) imaging in the Prostate Imaging Reporting and Data System (PI-RADS) version 2 for prostate multiparametric MR imaging by using data from a multireader study. Materials and Methods This HIPAA-compliant retrospective interpretation of prospectively acquired data was approved by the local ethics committee. Patients were treatment-naïve with endorectal coil 3-T multiparametric MR imaging. A total of 163 patients were evaluated, 110 with prostatectomy after multiparametric MR imaging and 53 with negative multiparametric MR imaging and systematic biopsy findings. Nine radiologists participated in this study and interpreted images in 58 patients, on average (range, 56-60 patients). Lesions were detected with PI-RADS version 2 and were compared with whole-mount prostatectomy findings. Probability of cancer detection for overall, T2-weighted, and diffusion-weighted (DW) imaging PI-RADS scores was calculated in the peripheral zone (PZ) and transition zone (TZ) by using generalized estimating equations. To determine dominant pulse sequence and benefit of dynamic contrast-enhanced (DCE) imaging, odds ratios (ORs) were calculated as the ratio of odds of cancer of two consecutive scores by logistic regression. Results A total of 654 lesions (420 in the PZ) were detected. The probability of cancer detection for PI-RADS category 2, 3, 4, and 5 lesions was 15.7%, 33.1%, 70.5%, and 90.7%, respectively. DW imaging outperformed T2-weighted imaging in the PZ (OR, 3.49 vs 2.45; P = .008). T2-weighted imaging performed better but did not clearly outperform DW imaging in the TZ (OR, 4.79 vs 3.77; P = .494). Lesions classified as PI-RADS category 3 at DW MR imaging and as positive at DCE imaging in the PZ showed a higher probability of cancer detection than did DCE-negative PI-RADS category 3 lesions (67.8% vs 40.0%, P = .02). The addition of DCE imaging

  19. The Minho Word Pool: Norms for imageability, concreteness, and subjective frequency for 3,800 Portuguese words.

    Science.gov (United States)

    Soares, Ana Paula; Costa, Ana Santos; Machado, João; Comesaña, Montserrat; Oliveira, Helena Mendes

    2017-06-01

    Words are widely used as stimuli in cognitive research. Because of their complexity, using words requires strict control of their objective (lexical and sublexical) and subjective properties. In this work, we present the Minho Word Pool (MWP), a dataset that provides normative values of imageability, concreteness, and subjective frequency for 3,800 (European) Portuguese words-three subjective measures that, in spite of being used extensively in research, have been scarce for Portuguese. Data were collected with 2,357 college students who were native speakers of European Portuguese. The participants rated 100 words drawn randomly from the full set for each of the three subjective indices, using a Web survey procedure (via a URL link). Analyses comparing the MWP ratings with those obtained for the same words from other national and international databases showed that the MWP norms are reliable and valid, thus providing researchers with a useful tool to support research in all neuroscientific areas using verbal stimuli. The MWP norms can be downloaded along with this article or from http://p-pal.di.uminho.pt/about/databases .

  20. Single session imaging of cerebellum at 7 Tesla: obtaining structure and function of multiple motor subsystems in individual subjects.

    Directory of Open Access Journals (Sweden)

    Melissa A Batson

    Full Text Available The recent increase in the use of high field MR systems is accompanied by a demand for acquisition techniques and coil systems that can take advantage of increased power and accuracy without being susceptible to increased noise. Physical location and anatomical complexity of targeted regions must be considered when attempting to image deeper structures with small nuclei and/or complex cytoarchitechtonics (i.e. small microvasculature and deep nuclei, such as the brainstem and the cerebellum (Cb. Once these obstacles are overcome, the concomitant increase in signal strength at higher field strength should allow for faster acquisition of MR images. Here we show that it is technically feasible to quickly and accurately detect blood oxygen level dependent (BOLD signal changes and obtain anatomical images of Cb at high spatial resolutions in individual subjects at 7 Tesla in a single one-hour session. Images were obtained using two high-density multi-element surface coils (32 channels in total placed beneath the head at the level of Cb, two channel transmission, and three-dimensional sensitivity encoded (3D, SENSE acquisitions to investigate sensorimotor activations in Cb. Two classic sensorimotor tasks were used to detect Cb activations. BOLD signal changes during motor activity resulted in concentrated clusters of activity within the Cb lobules associated with each task, observed consistently and independently in each subject: Oculomotor vermis (VI/VII and CrusI/II for pro- and anti-saccades; ipsilateral hemispheres IV-VI for finger tapping; and topographical separation of eye- and hand- activations in hemispheres VI and VIIb/VIII. Though fast temporal resolution was not attempted here, these functional patches of highly specific BOLD signal changes may reflect small-scale shunting of blood in the microvasculature of Cb. The observed improvements in acquisition time and signal detection are ideal for individualized investigations such as

  1. Evaluation of subjective image quality in relation to diagnostic task for cone beam computed tomography with different fields of view.

    Science.gov (United States)

    Lofthag-Hansen, Sara; Thilander-Klang, Anne; Gröndahl, Kerstin

    2011-11-01

    To evaluate subjective image quality for two diagnostic tasks, periapical diagnosis and implant planning, for cone beam computed tomography (CBCT) using different exposure parameters and fields of view (FOVs). Examinations were performed in posterior part of the jaws on a skull phantom with 3D Accuitomo (FOV 3 cm×4 cm) and 3D Accuitomo FPD (FOVs 4 cm×4 cm and 6 cm×6 cm). All combinations of 60, 65, 70, 75, 80 kV and 2, 4, 6, 8, 10 mA with a rotation of 180° and 360° were used. Dose-area product (DAP) value was determined for each combination. The images were presented, displaying the object in axial, cross-sectional and sagittal views, without scanning data in a random order for each FOV and jaw. Seven observers assessed image quality on a six-point rating scale. Intra-observer agreement was good (κw=0.76) and inter-observer agreement moderate (κw=0.52). Stepwise logistic regression showed kV, mA and diagnostic task to be the most important variables. Periapical diagnosis, regardless jaw, required higher exposure parameters compared to implant planning. Implant planning in the lower jaw required higher exposure parameters compared to upper jaw. Overall ranking of FOVs gave 4 cm×4 cm, 6 cm×6 cm followed by 3 cm×4 cm. This study has shown that exposure parameters should be adjusted according to diagnostic task. For this particular CBCT brand a rotation of 180° gave good subjective image quality, hence a substantial dose reduction can be achieved without loss of diagnostic information. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  2. Magnetic Resonance Image Sequence Influences the Relationship between Bone Marrow Lesions Volume and Pain: Data from the Osteoarthritis Initiative

    Directory of Open Access Journals (Sweden)

    Ming Zhang

    2015-01-01

    Full Text Available Subchondral bone marrow lesions (BMLs are related to structural and symptomatic osteoarthritis progression. However, it is unclear how sequence selection influences a quantitative BML measurement and its construct validity. We compared quantitative assessment of BMLs on intermediate-weighted fat suppressed (IW FS turbo spin echo and 3-dimensional dual echo steady state (3D DESS sequences. We used a customized software to measure 30 knees’ (24- and 48-month MR images BMLs on both sequences. The results showed that the IW FS sequences have much larger BML volumes (median: IW FS = 1840 mm3; DESS = 191 mm3 and BML volume change (between 24 and 48 months than DESS sequence and demonstrate more BML volume change. The 24-month BML volume on IW FS is correlated with BML volume on DESS (rs = 0.83. BML volume change on IW FS is not significantly correlated with change on DESS. The 24-month WOMAC pain is correlated with the 24-month BMLs on IW FS (rs = 0.39 but not DESS. The change in WOMAC pain is correlated with BML volume change on IW FS (rs = 0.37 but not DESS. Overall, BML quantification on IW FS offers better validity and statistical power than BML quantification on a 3D DESS sequence.

  3. [Magnetic resonance imaging assessment of the lateral pterygoid muscle in Class III malocclusion subjects].

    Science.gov (United States)

    Liu, Yue-hua; Yang, Xiao-jiang; Gao, Xiao-hui; Li, Yuan

    2012-01-01

    To analyze the relationship between Class III malocclusion and pathological changes in temporomandibular joint (TMJ) structures using magnetic resenonce imaging (MRI). Twenty-four Class III malocclusion adult patients and 10 normal control cases were included in the study. The characteristics of lateral pertygoid muscle (LPM) in the sample group and the control group were assessed. More pathological changes of LPM were found in Class III malocclusion adult patients (36 TMJ). The changes included hypertrophy, atrophy and contracture. And there was no relation between the pathological changes of LPM and the symptom of temporomandibular disorders (TMD). The frequency of pathological changes of LPM was greater in patients with Class III malocclusion than in the control group.

  4. Diffusion tensor imaging differentiates vascular parkinsonism from parkinsonian syndromes of degenerative origin in elderly subjects

    Energy Technology Data Exchange (ETDEWEB)

    Deverdun, Jérémy [Department of Neuroradiology, Montpellier University Hospital Center, Gui de Chauliac Hospital, Montpellier (France); Laboratoire Charles Coulomb, CNRS UMR 5221 - Université Montpellier II, Montpellier (France); I2FH, Institut d’Imagerie Fonctionnelle Humaine, Hôpital Gui de Chauliac, CHRU de, Montpellier (France); Menjot de Champfleur, Sophie [Department of Neuroradiology, Montpellier University Hospital Center, Gui de Chauliac Hospital, Montpellier (France); Clinique du Parc, Castelnau-le-Lez (France); Cabello-Aguilar, Simon [Department of Neuroradiology, Montpellier University Hospital Center, Gui de Chauliac Hospital, Montpellier (France); I2FH, Institut d’Imagerie Fonctionnelle Humaine, Hôpital Gui de Chauliac, CHRU de, Montpellier (France); Maury, Florence [Department of Neurology, Montpellier University Hospital Center, Gui de Chauliac Hospital, Montpellier (France); Molino, François [Laboratoire Charles Coulomb, CNRS UMR 5221 - Université Montpellier II, Montpellier (France); Institut de Génomique Fonctionnelle, UMR 5203 - INSERM U661 - Université Montpellier II - Université, Montpellier I (France); Charif, Mahmoud [Department of Neurology, Montpellier University Hospital Center, Gui de Chauliac Hospital, Montpellier (France); Leboucq, Nicolas [Department of Neuroradiology, Montpellier University Hospital Center, Gui de Chauliac Hospital, Montpellier (France); Ayrignac, Xavier; Labauge, Pierre [Department of Neurology, Montpellier University Hospital Center, Gui de Chauliac Hospital, Montpellier (France); and others

    2014-11-15

    Background and Purpose: The etiologic diagnosis of parkinsonian syndromes is of particular importance when considering syndromes of vascular or degenerative origin. The purpose of this study is to find differences in the white-matter architecture between those two groups in elderly patients. Materials and Methods: Thirty-five patients were prospectively included (multiple-system atrophy, n = 5; Parkinson's disease, n = 15; progressive supranuclear palsy, n = 9; vascular parkinsonism, n = 6), with a mean age of 76 years. Patients with multiple-system atrophy, progressive supranuclear palsy and Parkinson's disease were grouped as having parkinsonian syndromes of degenerative origin. Brain MRIs included diffusion tensor imaging. Fractional anisotropy and mean-diffusivity maps were spatially normalized, and group analyses between parkinsonian syndromes of degenerative origin and vascular parkinsonism were performed using a voxel-based approach. Results: Statistical parametric-mapping analysis of diffusion tensor imaging data showed decreased fractional anisotropy value in internal capsules bilaterally in patients with vascular parkinsonism compared to parkinsonian syndromes of degenerative origin (p = 0.001) and showed a lower mean diffusivity in the white matter of the left superior parietal lobule (p = 0.01). Fractional anisotropy values were found decreased in the middle cerebellar peduncles in multiple-system atrophy compared to Parkinson's disease and progressive supranuclear palsy. The mean diffusivity was increased in those regions for these subgroups. Conclusion: Clinically defined vascular parkinsonism was associated with decreased fractional anisotropy in the deep white matter (internal capsules) compared to parkinsonian syndromes of degenerative origin. These findings are consistent with previously published neuropathological data.

  5. Framingham coronary heart disease risk score can be predicted from structural brain images in elderly subjects.

    Directory of Open Access Journals (Sweden)

    Jane Maryam Rondina

    2014-12-01

    Full Text Available Recent literature has presented evidence that cardiovascular risk factors (CVRF play an important role on cognitive performance in elderly individuals, both those who are asymptomatic and those who suffer from symptoms of neurodegenerative disorders. Findings from studies applying neuroimaging methods have increasingly reinforced such notion. Studies addressing the impact of CVRF on brain anatomy changes have gained increasing importance, as recent papers have reported gray matter loss predominantly in regions traditionally affected in Alzheimer’s disease (AD and vascular dementia in the presence of a high degree of cardiovascular risk. In the present paper, we explore the association between CVRF and brain changes using pattern recognition techniques applied to structural MRI and the Framingham score (a composite measure of cardiovascular risk largely used in epidemiological studies in a sample of healthy elderly individuals. We aim to answer the following questions: Is it possible to decode (i.e., to learn information regarding cardiovascular risk from structural brain images enabling individual predictions? Among clinical measures comprising the Framingham score, are there particular risk factors that stand as more predictable from patterns of brain changes? Our main findings are threefold: i we verified that structural changes in spatially distributed patterns in the brain enable statistically significant prediction of Framingham scores. This result is still significant when controlling for the presence of the APOE 4 allele (an important genetic risk factor for both AD and cardiovascular disease. ii When considering each risk factor singly, we found different levels of correlation between real and predicted factors; however, single factors were not significantly predictable from brain images when considering APOE4 allele presence as covariate. iii We found important gender differences, and the possible causes of that finding are discussed.

  6. Registration techniques for speckle suppression in 2D LADAR image sequences

    Science.gov (United States)

    Sabo, Darren R.; Cain, Stephen C.

    2005-03-01

    Air Force Research Labs, Sensors Directorate has constructed and tested a coherent imaging system. The Laservision coherent imaging system resolution goals are compatible with long-range target identification based on the image characteristics of the target. The system received reflected coherent light from the laser using an optical telescope, which fed a CCD detector to collect the scene intensity. Registration of individual images remains a significant problem in the generation of accurate images collected using coherent imaging systems. An investigation of the performance of an image registration algorithm was conducted using data collected from a coherent optical imaging. The algorithm under study was implemented on a general-purpose computer running the MATLAB simulation environment. This paper documents the performance of the proposed technique compared to that of the cross-correlation algorithm.

  7. Radiographic image analysis of Anacardium othonianum Rizz (anacardiaceae achenes subjected to desiccation

    Directory of Open Access Journals (Sweden)

    Lílian Abadia da Silva

    2017-04-01

    Full Text Available Studies evaluating the internal morphology and seed quality of native species are essential for successful conservation programs. Our aim was to verify the efficiency of X-ray imagery in evaluating cashew-tree-of-the-cerrado (Anacardium othonianum Rizz. achene viability after desiccation. The achenes were collected at 12% water content (w.b. and dried in silica gel until they reached 10, 8, 6, and 4% (w.b.. The fruit morphology and the quality of the seeds were evaluated by X-ray test together with vigor, electrical conductivity and emergence tests. Achenes with different water contents were exposed to an X-ray machine at 18 kV for 11 s and were thereafter submitted to emergence tests. The images were analyzed, and the achenes were classified based on internal morphology as completely full, malformed, or empty. These results were compared to those from the emergence tests. The statistical design was a complete randomized factorial (5 x 3. Desiccation to 4% (w.b. did not damage or modify the internal structures. X-ray was efficient in evaluating the internal morphology and detecting achene quality, making it possible to remove empty and abnormal fruit and form vigorous seed lots, reducing the cost of storage and bedding plant production for this native species.

  8. Novel Method for Automated Analysis of Retinal Images: Results in Subjects with Hypertensive Retinopathy and CADASIL.

    Science.gov (United States)

    Cavallari, Michele; Stamile, Claudio; Umeton, Renato; Calimeri, Francesco; Orzi, Francesco

    2015-01-01

    Morphological analysis of the retinal vessels by fundoscopy provides noninvasive means for detecting and staging systemic microvascular damage. However, full exploitation of fundoscopy in clinical settings is limited by paucity of quantitative, objective information obtainable through the observer-driven evaluations currently employed in routine practice. Here, we report on the development of a semiautomated, computer-based method to assess retinal vessel morphology. The method allows simultaneous and operator-independent quantitative assessment of arteriole-to-venule ratio, tortuosity index, and mean fractal dimension. The method was implemented in two conditions known for being associated with retinal vessel changes: hypertensive retinopathy and Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL). The results showed that our approach is effective in detecting and quantifying the retinal vessel abnormalities. Arteriole-to-venule ratio, tortuosity index, and mean fractal dimension were altered in the subjects with hypertensive retinopathy or CADASIL with respect to age- and gender-matched controls. The interrater reliability was excellent for all the three indices (intraclass correlation coefficient ≥ 85%). The method represents simple and highly reproducible means for discriminating pathological conditions characterized by morphological changes of retinal vessels. The advantages of our method include simultaneous and operator-independent assessment of different parameters and improved reliability of the measurements.

  9. Novel Method for Automated Analysis of Retinal Images: Results in Subjects with Hypertensive Retinopathy and CADASIL

    Directory of Open Access Journals (Sweden)

    Michele Cavallari

    2015-01-01

    Full Text Available Morphological analysis of the retinal vessels by fundoscopy provides noninvasive means for detecting and staging systemic microvascular damage. However, full exploitation of fundoscopy in clinical settings is limited by paucity of quantitative, objective information obtainable through the observer-driven evaluations currently employed in routine practice. Here, we report on the development of a semiautomated, computer-based method to assess retinal vessel morphology. The method allows simultaneous and operator-independent quantitative assessment of arteriole-to-venule ratio, tortuosity index, and mean fractal dimension. The method was implemented in two conditions known for being associated with retinal vessel changes: hypertensive retinopathy and Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL. The results showed that our approach is effective in detecting and quantifying the retinal vessel abnormalities. Arteriole-to-venule ratio, tortuosity index, and mean fractal dimension were altered in the subjects with hypertensive retinopathy or CADASIL with respect to age- and gender-matched controls. The interrater reliability was excellent for all the three indices (intraclass correlation coefficient ≥ 85%. The method represents simple and highly reproducible means for discriminating pathological conditions characterized by morphological changes of retinal vessels. The advantages of our method include simultaneous and operator-independent assessment of different parameters and improved reliability of the measurements.

  10. Volumetric MRI thermometry using a three-dimensional stack-of-stars echo-planar imaging pulse sequence.

    Science.gov (United States)

    Jonathan, Sumeeth V; Grissom, William A

    2017-08-07

    To measure temperature over a large brain volume with fine spatiotemporal resolution. A three-dimensional stack-of-stars echo-planar imaging sequence combining echo-planar imaging and radial sampling with golden angle spacing was implemented at 3T for proton resonance frequency-shift temperature imaging. The sequence acquires a 188x188x43 image matrix with 1.5x1.5x2.75 mm3 spatial resolution. Temperature maps were reconstructed using sensitivity encoding (SENSE) image reconstruction followed by the image domain hybrid method, and using the k-space hybrid method. In vivo temperature maps were acquired without heating to measure temperature precision in the brain, and in a phantom during high-intensity focused ultrasound sonication. In vivo temperature standard deviation was less than 1°C at dynamic scan times down to 0.75 s. For a given frame rate, scanning at a minimum repetition time (TR) with minimum acceleration yielded the lowest standard deviation. With frame rates around 3 s, the scan was tolerant to a small number of receive coils, and temperature standard deviation was 48% higher than a standard two-dimensional Fourier transform temperature mapping scan, but provided whole-brain coverage. Phantom temperature maps with no visible aliasing were produced for dynamic scan times as short as 0.38 s. k-Space hybrid reconstructions were more tolerant to acceleration. Three-dimensional stack-of-stars echo-planar imaging temperature mapping provides volumetric brain coverage and fine spatiotemporal resolution. Magn Reson Med, 2017. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  11. Functional multiparametric magnetic resonance imaging of the kidneys using blood oxygen level dependent and diffusion-weighted sequences.

    Science.gov (United States)

    Giannarini, Gianluca; Kessler, Thomas M; Roth, Beat; Vermathen, Peter; Thoeny, Harriet C

    2014-08-01

    Little data are available on noninvasive magnetic resonance imaging based assessment of renal function during upper urinary tract obstruction. We determined whether functional multiparametric kidney magnetic resonance imaging could monitor the treatment response in cases of acute unilateral upper urinary tract obstruction. Between January 2008 and January 2010, 18 patients with acute unilateral upper urinary tract obstruction due to calculi were prospectively enrolled to undergo kidney magnetic resonance imaging with conventional, blood oxygen level dependent and diffusion-weighted sequences upon emergency hospital admission and after release of obstruction. We assessed functional imaging parameters of obstructed and contralateral unobstructed kidneys derived from blood oxygen level dependent (apparent spin relaxation rate) and diffusion-weighted (total apparent diffusion coefficient, pure diffusion coefficient and perfusion fraction) sequences during acute upper urinary tract obstruction and after its release. During acute obstruction the apparent spin relaxation rate and perfusion fraction were lower in the cortex (p=0.020 and 0.031) and medulla (p=0.012 and 0.190, respectively) of obstructed kidneys compared to contralateral unobstructed kidneys. After obstruction release the apparent spin relaxation rate and perfusion fraction increased in the cortex (p=0.016 and 0.004) and medulla (p=0.071 and 0.044, respectively) of formerly obstructed kidneys to values similar to those in contralateral kidneys. Total apparent diffusion coefficient and pure diffusion coefficient values did not significantly differ between obstructed and contralateral unobstructed kidneys during or after obstruction. In our patients with acute unilateral upper urinary tract obstruction due to calculi functional kidney magnetic resonance imaging using blood oxygen level dependent and diffusion-weighted sequences enabled us to monitor pathophysiological changes in obstructed kidneys during

  12. Human xanthine dehydrogenase cDNA sequence and protein in an atypical case of type I xanthinuria in comparison with normal subjects.

    Science.gov (United States)

    Yamamoto, T; Moriwaki, Y; Shibutani, Y; Matsui, K; Ueo, T; Takahashi, S; Tsutsumi, Z; Hada, T

    2001-02-01

    To investigate the properties of xanthine dehydrogenase/xanthine oxidase (XDH/XO) deficiency in a patient with atypical type I xanthinuria, as indicated by oxypurine data, a cDNA sequence encoding XDH, XDH/XO immunoblot analysis and a competitive PCR assay were performed, and the results were compared with those of normal subjects. The xanthine dehydrogenase cDNA sequence of the patient was consistent with the controls, while immunologically reactive 150 kD XDH/XO protein was not present in the xanthinuric duodenal mucosa, unlike the control duodenal mucosa. In addition, a decrease in XDH/XO messenger RNA was found by competitive PCR. These results suggest that atypical type I xanthinuria is due to a decrease in messenger RNA of XDH/XO. Furthermore, it was considered that this decrease could explain the normal plasma level and near normal urinary excretion of hypoxanthine seen in this case of xanthinuria, though XDH/XO activity and protein were not detected spectrophotometrically and immunologically, respectively.

  13. Magnetic resonance imaging of the normal pituitary gland using ultrashort TE (UTE) pulse sequences (REV 1.0)

    Energy Technology Data Exchange (ETDEWEB)

    Portman, Olivia; Flemming, Stephen; Cox, Jeremy P.D.; Johnston, Desmond G. [Imperial College Faculty of Medicine, St Mary' s Hospital, Endocrinology and Metabolic Medicine, London (United Kingdom); Bydder, Graeme M. [University of California, San Diego, Department of Radiology, San Diego, CA (United States)

    2008-03-15

    The purpose of this study was to examine the normal pituitary gland in male subjects with ultrashort echo time (TE) pulse sequences, describe its appearance and measure its signal intensity before and after contrast enhancement. Eleven male volunteers (mean age 57.1 years; range 36-81 years) were examined with a fat-suppressed ultrashort TE (= 0.08 ms) pulse sequence. The studies were repeated after the administration of intravenous gadodiamide. The MR scans were examined for gland morphology and signal intensity before and after enhancement. Endocrinological evaluation included baseline pituitary function tests and a glucagon stimulatory test to assess pituitary cortisol and growth hormone reserve. High signal intensity was observed in the anterior pituitary relative to the brain in nine of the 11 subjects. These regions involved the whole of the anterior pituitary in three subjects, were localised to one side in two examples and were seen inferiorly in three subjects. Signal intensities relative to the brain increased with age, with a peak around the sixth or seventh decade and decreasing thereafter. Overall, the pituitary function tests were considered to be within normal limits and did not correlate with pituitary gland signal intensity. The anterior pituitary shows increased signal intensity in normal subjects when examined with T{sub 1}-weighted ultrashort TE pulse sequences. The cause of this increased intensity is unknown, but fibrosis and iron deposition are possible candidates. The variation in signal intensity with age followed the temporal pattern of iron content observed at post mortem. No relationship with endocrine status was observed. (orig.)

  14. Quantitative analysis of fluorescence lifetime measurements of the macula using the fluorescence lifetime imaging ophthalmoscope in healthy subjects.

    Science.gov (United States)

    Dysli, Chantal; Quellec, Gwénolé; Abegg, Mathias; Menke, Marcel N; Wolf-Schnurrbusch, Ute; Kowal, Jens; Blatz, Johannes; La Schiazza, Olivier; Leichtle, Alexander B; Wolf, Sebastian; Zinkernagel, Martin S

    2014-04-03

    Fundus autofluorescence (FAF) cannot only be characterized by the intensity or the emission spectrum, but also by its lifetime. As the lifetime of a fluorescent molecule is sensitive to its local microenvironment, this technique may provide more information than fundus autofluorescence imaging. We report here the characteristics and repeatability of FAF lifetime measurements of the human macula using a new fluorescence lifetime imaging ophthalmoscope (FLIO). A total of 31 healthy phakic subjects were included in this study with an age range from 22 to 61 years. For image acquisition, a fluorescence lifetime ophthalmoscope based on a Heidelberg Engineering Spectralis system was used. Fluorescence lifetime maps of the retina were recorded in a short- (498-560 nm) and a long- (560-720 nm) spectral channel. For quantification of fluorescence lifetimes a standard ETDRS grid was used. Mean fluorescence lifetimes were shortest in the fovea, with 208 picoseconds for the short-spectral channel and 239 picoseconds for the long-spectral channel, respectively. Fluorescence lifetimes increased from the central area to the outer ring of the ETDRS grid. The test-retest reliability of FLIO was very high for all ETDRS areas (Spearman's ρ = 0.80 for the short- and 0.97 for the long-spectral channel, P macula in healthy subjects. By using a custom-built software, we were able to quantify fluorescence lifetimes within the ETDRS grid. Establishing a clinically accessible standard against which to measure FAF lifetimes within the retina is a prerequisite for future studies in retinal disease.

  15. Effect of propofol on the medial temporal lobe emotional memory system: a functional magnetic resonance imaging study in human subjects.

    Science.gov (United States)

    Pryor, K O; Root, J C; Mehta, M; Stern, E; Pan, H; Veselis, R A; Silbersweig, D A

    2015-07-01

    Subclinical doses of propofol produce anterograde amnesia, characterized by an early failure of memory consolidation. It is unknown how propofol affects the amygdala-dependent emotional memory system, which modulates consolidation in the hippocampus in response to emotional arousal and neurohumoral stress. We present an event-related functional magnetic resonance imaging study of the effects of propofol on the emotional memory system in human subjects. Thirty-five healthy subjects were randomized to receive propofol, at an estimated brain concentration of 0.90 μg ml(-1), or placebo. During drug infusion, emotionally arousing and neutral images were presented in a continuous recognition task, while blood-oxygen-level-dependent activation responses were acquired. After a drug-free interval of 2 h, subsequent memory for successfully encoded items was assessed. Imaging analysis was performed using statistical parametric mapping and behavioural analysis using signal detection models. Propofol had no effect on the stereotypical amygdalar response to emotional arousal, but caused marked suppression of the hippocampal response. Propofol caused memory performance to become uncoupled from amygdalar activation, but it remained correlated with activation in the posterior hippocampus, which decreased in proportion to amnesia. Propofol is relatively ineffective at suppressing amygdalar activation at sedative doses, but abolishes emotional modulation and causes amnesia via mechanisms that commonly involve hyporesponsiveness of the hippocampus. These findings raise the possibility that amygdala-dependent fear systems may remain intact even when a patient has diminished memory of events. This may be of clinical importance in the perioperative development of fear-based psychopathologies, such as post-traumatic stress disorder. NCT00504894. © The Author 2015. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions

  16. Towards the identification of imaging biomarkers in schizophrenia, using multivariate pattern classification at a single-subject level.

    Science.gov (United States)

    Zarogianni, Eleni; Moorhead, Thomas W J; Lawrie, Stephen M

    2013-01-01

    Standard univariate analyses of brain imaging data have revealed a host of structural and functional brain alterations in schizophrenia. However, these analyses typically involve examining each voxel separately and making inferences at group-level, thus limiting clinical translation of their findings. Taking into account the fact that brain alterations in schizophrenia expand over a widely distributed network of brain regions, univariate analysis methods may not be the most suited choice for imaging data analysis. To address these limitations, the neuroimaging community has turned to machine learning methods both because of their ability to examine voxels jointly and their potential for making inferences at a single-subject level. This article provides a critical overview of the current and foreseeable applications of machine learning, in identifying imaging-based biomarkers that could be used for the diagnosis, early detection and treatment response of schizophrenia, and could, thus, be of high clinical relevance. We discuss promising future research directions and the main difficulties facing machine learning researchers as far as their potential translation into clinical practice is concerned.

  17. Tract Orientation and Angular Dispersion Deviation Indicator (TOADDI): A framework for single-subject analysis in diffusion tensor imaging.

    Science.gov (United States)

    Koay, Cheng Guan; Yeh, Ping-Hong; Ollinger, John M; İrfanoğlu, M Okan; Pierpaoli, Carlo; Basser, Peter J; Oakes, Terrence R; Riedy, Gerard

    2016-02-01

    The purpose of this work is to develop a framework for single-subject analysis of diffusion tensor imaging (DTI) data. This framework is termed Tract Orientation and Angular Dispersion Deviation Indicator (TOADDI) because it is capable of testing whether an individual tract as represented by the major eigenvector of the diffusion tensor and its corresponding angular dispersion are significantly different from a group of tracts on a voxel-by-voxel basis. This work develops two complementary statistical tests based on the elliptical cone of uncertainty, which is a model of uncertainty or dispersion of the major eigenvector of the diffusion tensor. The orientation deviation test examines whether the major eigenvector from a single subject is within the average elliptical cone of uncertainty formed by a collection of elliptical cones of uncertainty. The shape deviation test is based on the two-tailed Wilcoxon-Mann-Whitney two-sample test between the normalized shape measures (area and circumference) of the elliptical cones of uncertainty of the single subject against a group of controls. The False Discovery Rate (FDR) and False Non-discovery Rate (FNR) were incorporated in the orientation deviation test. The shape deviation test uses FDR only. TOADDI was found to be numerically accurate and statistically effective. Clinical data from two Traumatic Brain Injury (TBI) patients and one non-TBI subject were tested against the data obtained from a group of 45 non-TBI controls to illustrate the application of the proposed framework in single-subject analysis. The frontal portion of the superior longitudinal fasciculus seemed to be implicated in both tests (orientation and shape) as significantly different from that of the control group. The TBI patients and the single non-TBI subject were well separated under the shape deviation test at the chosen FDR level of 0.0005. TOADDI is a simple but novel geometrically based statistical framework for analyzing DTI data. TOADDI may be

  18. 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 68Ge flood phantom was demonstrated within 0.34%. Normalized sensitivity was stable during simultaneous scanning within 0.3%. Scatter fraction measured with a 68Ge 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

  19. Automatic delamination defect detection in radiographic sequence of rocket boosters; Determination automatique de defauts de delaminage dans des sequences d'images radiographiques de propulseurs de fusee

    Energy Technology Data Exchange (ETDEWEB)

    Rebuffel, V.; Pires, S. [CEA Grenoble, Lab. d' Electronique et de Technologie de l' Informatique (LETI/DSIS/SSBS), 38 (France); Caplier, A. [Institut National Polytechnique, 38 - Grenoble (France); Lamarque, P. [SNPE, 75 - Paris (France)

    2003-07-01

    Solid rocket motors are routinely examined in real-time X-ray radioscopic mode. The large and cylindrical boosters are rotating between a high energy source and a two dimensional detector. The purpose of this control is to detect possible defects all through the sample. In the tangential configuration, the part of the object that intersects the X-rays beam is the peripheral one, allowing to detect the delamination defect between the propellant and the external metal envelope. But the defect detectability is very poor due to the strong attenuation of the X-rays through the motors. During the rotation of the booster, the system acquires a sequence of radiographs where the defects are visible over several successive instants. We have previously developed a real-time tomo-synthesis system, processing the radiographs on line, and based on a tomo-synthesis reconstruction algorithm in order to improve the signal-to-noise ratio. This system is installed at the industrial site of Kourou, and is currently used by the operators in charge of the visual inspection of the boosters. In this paper, we present a method that processes the digital images obtained by the system in the purpose of automatically extracting the delamination defects. Due to the size and the poor contrast of the defects, a single image is not sufficient to perform this detection. A spatio-temporal aspect is required for the algorithm to be robust and efficient. In a first step, the proposed method computes the apparent local displacement between the current radiograph and a reference one. This reference image is acquired at the beginning of the rotation, with few noise, and is supposed to be defect free. The apparent displacement is due to the non-perfect rotation positioning. It may be uniform or not, depending on the deformation of the insulation liner of the metallic wall. The images are then registered and compared. On the resulting difference image we apply a smoothed threshold to obtain an

  20. Radiographic alveolar bone loss in untreated Taiwan Chinese subjects with adult periodontitis measured by the digital scanning radiographic image analysis method

    National Research Council Canada - National Science Library

    Hou, G-L; Hung, C-C; Yang, Y-S; Shieh, T-Y; Tsai, C-C

    2003-01-01

    To determine differences in radiographic alveolar bone loss (RABL) by age group, gender and tooth type in subjects with adult periodontitis using the digital scanning radiographic image analysis (DSRIA) method...

  1. The facial expression of schizophrenic patients applied with infrared thermal facial image sequence

    National Research Council Canada - National Science Library

    Bo-Lin Jian; Chieh-Li Chen; Wen-Lin Chu; Min-Wei Huang

    2017-01-01

    .... Thus, this study used non-contact infrared thermal facial images (ITFIs) to analyze facial temperature changes evoked by different emotions in moderately and markedly ill schizophrenia patients...

  2. NON-UNIFORM HEATING COMPENSATION FOR SEQUENCES OF THERMAL IMAGES USING MEDIAN FILTERING

    National Research Council Canada - National Science Library

    ANDRÉS DAVID RESTREPO GIRÓN; HUMBERTO LOAIZA CORREA

    2013-01-01

      Herein, we introduce a new thermal contrast enhancement procedure for infrared images, acquired from a non-destructive evaluation of composite slabs through active infrared thermography experiments...

  3. Subject-specific 2D/3D image registration and kinematics-driven musculoskeletal model of the spine.

    Science.gov (United States)

    Eskandari, A H; Arjmand, N; Shirazi-Adl, A; Farahmand, F

    2017-05-24

    An essential input to the musculoskeletal (MS) trunk models that estimate muscle and spine forces is kinematics of the thorax, pelvis, and lumbar vertebrae. While thorax and pelvis kinematics are usually measured via skin motion capture devices (with inherent errors on the proper identification of the underlying bony landmarks and the relative skin-sensor-bone movements), those of the intervening lumbar vertebrae are commonly approximated at fixed proportions based on the thorax-pelvis kinematics. This study proposes an image-based kinematics measurement approach to drive subject-specific (musculature, geometry, mass, and center of masses) MS models. Kinematics of the thorax, pelvis, and individual lumbar vertebrae as well as disc inclinations, gravity loading, and musculature were all measured via different imaging techniques. The model estimated muscle and lumbar forces in various upright and flexed postures in which kinematics were obtained using upright fluoroscopy via 2D/3D image registration. Predictions of this novel image-kinematics-driven model (Img-KD) were compared with those of the traditional kinematics-driven (T-KD) model in which individual lumbar vertebral rotations were assumed based on thorax-pelvis orientations. Results indicated that while differences between Img-KD and T-KD models remained small for the force in the global muscles (attached to the thoracic cage) (muscles (attached to the lumbar vertebrae). Assuming that the skin-based measurements of thorax and pelvis kinematics are accurate enough, the T-KD model predictions of spinal forces remain reliable. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. An improved Fourier-based sub-pixel image registration algorithm for raw image sequence of LASIS

    Science.gov (United States)

    Ma, Xiaolong; Yang, Jianfeng; Qiao, Weidong; Xue, Bin

    2008-03-01

    Previous studies indicate that parallel computing for hyperspectral remote sensing synthetic image generation is quite feasible. However, due to the limitation of computing ability within single cluster, one can only generate three bands and a 1000*1000 pixels image in a reasonable time period even using a 40-50 node parallel computing cluster. In this paper, we discuss the capability of using Grid computing where the so-called eScience or cyberinfrastructure is utilized to integrate distributed computing resources to act as a single virtual computer with huge scientific computational abilities and storage spaces. The technique demonstrated in this paper demonstrates the feasibility of a Grid-Enabled Monte Carlo Hyperspectral Synthetic Image Remote Sensing Model (GRID-MCHSIM) for future coastal water quality remote sensing algorithm developments and detection of bottom features and targets in water.

  5. Intra-Rater Reliability of Rehabilitative Ultrasound Imaging for Multifidus Muscles Thickness and Cross Section Area in Healthy Subjects.

    Science.gov (United States)

    Hosseinifar, Mohammad; Akbari, Asghar; Ghiasi, Fateme

    2015-07-07

    Rehabilitative Ultrasound Imaging (RUSI) must be valuable method for research and rehabilitation. So, the reliability of its measurements must be determined. The purpose of this study was to evaluate the intra-rater reliability of RUSI for measurement of multifidus (MF) muscles cross section areas (CSAs), bladder wall diameter, and thickness of MF muscles between 2 sessions in healthy subjects. Fifteen healthy subjects through simple non-probability sampling participated in this single-group repeated-measures reliability study. MF muscles thickness at rest and during contraction, MF muscles CSAs at rest, and bladder diameters at rest and during pelvic floor muscles (PFM) contraction were measured through RUSI. Pearson's correlation coefficient test was used to determine intra-rater reliability of variables. The results showed that intra-class correlation Coefficient (ICCs) values with 95% confidence interval (CI) and the standard error of the measurement (SEM) were good to excellent agreement for a single investigator between measurement occasions. The intra-rater reliability for the bladder wall displacement was high (ICCs for rest and PFM contraction state: 0.96 and 0.95 respectively), for the MF muscles CSAs at the L4 level was good to high (ICCs 0.75 and 0.91 for right (Rt) and left (Lt) side respectively), and for the thickness of MF muscles at two levels, at rest and during two tasks was moderate to high (ICCs: 0.64 to 0.87). The Trans-Abdominal (TA) method of RUSI is a reliable method to quantify the PFM contraction in healthy subjects. Also, the RUSI is a reliable method to measure the MF muscles CSAs, the MF muscles thickness at rest and during functional tasks in healthy subjects.

  6. Students' Images and Their Understanding of Definitions of the Limit of a Sequence

    Science.gov (United States)

    Roh, Kyeong Hah

    2008-01-01

    There are many studies on the role of images in understanding the concept of limit. However, relatively few studies have been conducted on how students' understanding of the rigorous definition of limit is influenced by the images of limit that the students have constructed through their previous learning. This study explored how calculus…

  7. Comparison of registration techniques for speckle suppression in 2D ladar image sequences

    Science.gov (United States)

    MacDonald, Adam; Armstrong, Ernest; Cain, Stephen C.

    2004-11-01

    Registration of individual images remains a significant problem in the generation of accurate images collected using coherent imaging systems. An investigation of the performance of eight distinct image registration algorithms was conducted using data collected from a coherent optical imaging system developed by the Air Force Research Laboratories, Sensors Division, ARFL/SNJT. A total of 400 images of three distinct scenes were collected by SRJT and made available to the Air Force Institute of Technology (AFIT) for this study. Scenery was collected at 3 and 10 kilometers of wheeled vehicles supporting resolution and uniform target boards. The algorithms under study were developed by scientists and engineers at AFRL, and had varying levels of performance in terms of image miss-registration and execution time. These eight algorithms were implemented on a general-purpose computer running the MATLAB simulation environment. The algorithms compared included: block-match, cross-correlation, cross-search, directional-search, gradient-based, hierarchical-block, three-step, and vector-block methods. It was found that the cross-correlation, gradient-based and vector-block search techniques typically had the lowest error metric. The vector-block and cross-correlation methods proved to have the fastest execution times, while not suffering significant error degradation when estimating the registration shift of the test images.

  8. Energy function behavior in optimization based image sequence stabilization in presence of moving objects

    NARCIS (Netherlands)

    Karimi Nejadasl, F.; Gorte, B.G.H.; Snellen, M.M.; Hoogendoorn, S.P.

    2008-01-01

    In this paper, we address the registration of two images as an optimization problem within indicated bounds. Our contribution is to identify such situations where the optimum value represents the real transformation parameters between the two images. Consider for example Mean Square Error (MSE) as

  9. 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 and on the......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...... and on the other hand facial analysis systems. The proposed system in this paper deals with exactly this problem. Our approach is to apply a reconstruction-based super-resolution algorithm. Such an algorithm, however, has two main problems: first, it requires relatively similar images with not too much noise...

  10. Ultra-fast speech comprehension in blind subjects engages primary visual cortex, fusiform gyrus, and pulvinar – a functional magnetic resonance imaging (fMRI) study

    Science.gov (United States)

    2013-01-01

    Background Individuals suffering from vision loss of a peripheral origin may learn to understand spoken language at a rate of up to about 22 syllables (syl) per second - exceeding by far the maximum performance level of normal-sighted listeners (ca. 8 syl/s). To further elucidate the brain mechanisms underlying this extraordinary skill, functional magnetic resonance imaging (fMRI) was performed in blind subjects of varying ultra-fast speech comprehension capabilities and sighted individuals while listening to sentence utterances of a moderately fast (8 syl/s) or ultra-fast (16 syl/s) syllabic rate. Results Besides left inferior frontal gyrus (IFG), bilateral posterior superior temporal sulcus (pSTS) and left supplementary motor area (SMA), blind people highly proficient in ultra-fast speech perception showed significant hemodynamic activation of right-hemispheric primary visual cortex (V1), contralateral fusiform gyrus (FG), and bilateral pulvinar (Pv). Conclusions Presumably, FG supports the left-hemispheric perisylvian “language network”, i.e., IFG and superior temporal lobe, during the (segmental) sequencing of verbal utterances whereas the collaboration of bilateral pulvinar, right auditory cortex, and ipsilateral V1 implements a signal-driven timing mechanism related to syllabic (suprasegmental) modulation of the speech signal. These data structures, conveyed via left SMA to the perisylvian “language zones”, might facilitate – under time-critical conditions – the consolidation of linguistic information at the level of verbal working memory. PMID:23879896

  11. Effect of inspiration on airway dimensions measured in maximal inspiration CT images of subjects without airflow limitation

    DEFF Research Database (Denmark)

    Petersen, Jens; Wille, Mathilde M.W.; Raket, Lars Lau

    2014-01-01

    . Automated software was utilized to segment lungs and airways, identify segmental bronchi, and match airway branches in all images of the same subject. Inspiration level was defined as segmented total lung volume (TLV) divided by predicted total lung capacity (pTLC). Mixed-effects models were used to predict...... relative change in lumen diameter (ALD) and wall thickness (AWT) in airways of generation 0 (trachea) to 7 and segmental bronchi (R1-R10 and L1-L10) from relative changes in inspiration level. RESULTS: Relative changes in ALD were related to relative changes in TLV/pTLC, and this distensibility increased...... with generation (p TLC in generation 3--7 (p 

  12. Functional magnetic resonance imaging study of external source memory and its relation to cognitive insight in non-clinical subjects.

    Science.gov (United States)

    Buchy, Lisa; Hawco, Colin; Bodnar, Michael; Izadi, Sarah; Dell'Elce, Jennifer; Messina, Katrina; Lepage, Martin

    2014-09-01

    Previous research has linked cognitive insight (a measure of self-reflectiveness and self-certainty) in psychosis with neurocognitive and neuroanatomical disturbances in the fronto-hippocampal neural network. The authors' goal was to use functional magnetic resonance imaging (fMRI) to investigate the neural correlates of cognitive insight during an external source memory paradigm in non-clinical subjects. At encoding, 24 non-clinical subjects travelled through a virtual city where they came across 20 separate people, each paired with a unique object in a distinct location. fMRI data were then acquired while participants viewed images of the city, and completed source recognition memory judgments of where and with whom objects were seen, which is known to involve prefrontal cortex. Cognitive insight was assessed with the Beck Cognitive Insight Scale. External source memory was associated with neural activity in a widespread network consisting of frontal cortex, including ventrolateral prefrontal cortex (VLPFC), temporal and occipital cortices. Activation in VLPFC correlated with higher self-reflectiveness and activation in midbrain correlated with lower self-certainty during source memory attributions. Neither self-reflectiveness nor self-certainty significantly correlated with source memory accuracy. By means of virtual reality and in the context of an external source memory paradigm, the study identified a preliminary functional neural basis for cognitive insight in the VLPFC in healthy people that accords with our fronto-hippocampal theoretical model as well as recent neuroimaging data in people with psychosis. The results may facilitate the understanding of the role of neural mechanisms in psychotic disorders associated with cognitive insight distortions. © 2014 The Authors. Psychiatry and Clinical Neurosciences © 2014 Japanese Society of Psychiatry and Neurology.

  13. New Imaging Strategies Using a Motion-Resistant Liver Sequence in Uncooperative Patients

    Science.gov (United States)

    Kim, Bong Soo; Lee, Kyung Ryeol; Goh, Myeng Ju

    2014-01-01

    MR imaging has unique benefits for evaluating the liver because of its high-resolution capability and ability to permit detailed assessment of anatomic lesions. In uncooperative patients, motion artifacts can impair the image quality and lead to the loss of diagnostic information. In this setting, the recent advances in motion-resistant liver MR techniques, including faster imaging protocols (e.g., dual-echo magnetization-prepared rapid-acquisition gradient echo (MP-RAGE), view-sharing technique), the data under-sampling (e.g., gradient recalled echo (GRE) with controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA), single-shot echo-train spin-echo (SS-ETSE)), and motion-artifact minimization method (e.g., radial GRE with/without k-space-weighted image contrast (KWIC)), can provide consistent, artifact-free images with adequate image quality and can lead to promising diagnostic performance. Understanding of the different motion-resistant options allows radiologists to adopt the most appropriate technique for their clinical practice and thereby significantly improve patient care. PMID:25243115

  14. Modeling camera orientation and 3D structure from a sequence of images taken by a perambulating commercial video camera

    Science.gov (United States)

    M-Rouhani, Behrouz; Anderson, James A. D. W.

    1997-04-01

    In this paper we report the degree of reliability of image sequences taken by off-the-shelf TV cameras for modeling camera rotation and reconstructing 3D structure using computer vision techniques. This is done in spite of the fact that computer vision systems usually use imaging devices that are specifically designed for the human vision. Our scenario consists of a static scene and a mobile camera moving through the scene. The scene is any long axial building dominated by features along the three principal orientations and with at least one wall containing prominent repetitive planar features such as doors, windows bricks etc. The camera is an ordinary commercial camcorder moving along the axial axis of the scene and is allowed to rotate freely within the range +/- 10 degrees in all directions. This makes it possible that the camera be held by a walking unprofessional cameraman with normal gait, or to be mounted on a mobile robot. The system has been tested successfully on sequence of images of a variety of structured, but fairly cluttered scenes taken by different walking cameramen. The potential application areas of the system include medicine, robotics and photogrammetry.

  15. Subjective well-being, body image, and functional capacity in people candidate for or undergoing bariatric surgery

    Directory of Open Access Journals (Sweden)

    Mayra Juliana Galvis-Aparicio

    2017-07-01

    Full Text Available This paper presents two studies that aimed (1 at assessing and comparing the subjective well-being (SWB, and functional capacity and body image of people with morbid obesity, candidate for or undergoing bariatric surgery (BS, and (2 at identifying the relationship among the components of SWB, BMI, functional capacity, and body image. The sample was composed by 48 patients in pre-surgery period, and 29 in post-surgery. Instruments used were the Life Satisfaction Scale, the Positive and Negative Affect Scale, WHODAS 2.0, the Brazilian scale of figures and silhouettes, and thebateria fatorial da personalidade. Statistically significant differences were found between both groups in all the variables, except positive affect, comprehension and communication, and relationships with others. FC was correlated to all the components of SWB and contributed to explaining the variance of life satisfaction and negative affect. Personality traits turned out to be more important than other variables for explaining the variance of positive affect.

  16. Using cone-beam CT as a low-dose 3D imaging technique for the extremities: initial experience in 50 subjects

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Ambrose J.; Chang, Connie Y.; Palmer, William E. [Massachusetts General Hospital, Department of Radiology, Division of Musculoskeletal Imaging and Intervention, Boston, MA (United States); Thomas, Bijoy J. [Universal College of Medical Sciences, Department of Radiology, Bhairahawa (Nepal); MacMahon, Peter J. [Mater Misericordiae University Hospital, Department of Radiology, Dublin 7 (Ireland)

    2015-06-01

    To prospectively evaluate a dedicated extremity cone-beam CT (CBCT) scanner in cases with and without orthopedic hardware by (1) comparing its imaging duration and image quality to those of radiography and multidetector CT (MDCT) and (2) comparing its radiation dose to that of MDCT. Written informed consent was obtained for all subjects for this IRB-approved, HIPAA-compliant study. Fifty subjects with (1) fracture of small bones, (2) suspected intraarticular fracture, (3) fracture at the site of complex anatomy, or (4) a surgical site difficult to assess with radiography alone were recruited and scanned on an extremity CBCT scanner prior to FDA approval. Same-day radiographs were performed in all subjects. Some subjects also underwent MDCT within 1 month of CBCT. Imaging duration and image quality were compared between CBCT and radiographs. Imaging duration, effective radiation dose, and image quality were compared between CBCT and MDCT. Fifty-one CBCT scans were performed in 50 subjects. Average imaging duration was shorter for CBCT than radiographs (4.5 min vs. 6.6 min, P = 0.001, n = 51) and MDCT (7.6 min vs. 10.9 min, P = 0.01, n = 7). Average estimated effective radiation dose was less for CBCT than MDCT (0.04 mSv vs. 0.13 mSv, P = 0.02, n = 7). CBCT images yielded more diagnostic information than radiographs in 23/51 cases and more diagnostic information than MDCT in 1/7 cases, although radiographs were superior for detecting hardware complications. CBCT performs high-resolution imaging of the extremities using less imaging time than radiographs and MDCT and lower radiation dose than MDCT. (orig.)

  17. Diffusion Weighted Imaging in Magnetic Resonance Imaging for Prostate Cancer Diagnosis: Current Efficiency as a Standalone Sequence for an Unenhanced MRI Experience - a Pilot Study

    Directory of Open Access Journals (Sweden)

    Nechifor-Boilă I.A.

    2016-03-01

    Full Text Available Objective: Diffusion Weighted Imaging (DWI is the main sequence in the multiparametric prostate MRI protocol together with T2 and dynamic contrast-enhanced T1, leading to detection rates up to 60% in prostate cancer diagnosis. However, the use of intravenous contrast can have severe side-effects, making the use of unenhanced MRI sequences essential. The aim of our study was to assess the feasibility and efficiency of DWI as a standalone MRI technique for prostate cancer diagnosis. Methods: We performed a prospective cohort study at our department (09.2014-05.2015 and formed a study lot consisting in five prostate cancer patients that were scheduled for radical prostatectomy. Multiparametric MRI was performed (with DWI and T2 sequences and the images were interpreted according to the PI-RADS system. The final histopathological result after prostatectomy served as gold standard. Results: A series of 9 lesions were detected and analyzed on DWI. At qualitative interpretation, DWI had a sensitivity of 85.7% and a specificity of 50%. The corresponding positive and negative likelihood ratios were 1.71 and 0.286, respectively (p=0.417. ADC analysis revealed a mean value of 1.2*10-3mm2/s for the benign lesions while the corresponding value was 0.8*10-3 for the malignant ones, regardless of tumor size and Gleason scoring. Conclusion: DWI is a feasible technique in the current clinical environment, with a good sensitivity and a medium specificity. Furthermore, an association to the anatomical T2 sequence could enhance the diagnostic efficiency of DWI and should be assessed in larger studies.

  18. Using functional Magnetic Resonance Imaging to differentiate between Healthy Aging subjects, Mild Cognitive Impairment, and Alzheimer’s Patients

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Oghabian

    2010-01-01

    Full Text Available

    Back ground: Alzheimer's disease is the most common form of dementia which is still difficult to be differentiated from other types of brain disorders. Moreover, Mild Cognitive Impairment refers to the presence of cognitive impairments that is not severe enough to meet the criteria of dementia, and its diagnosis in early stages is so critical. There is currently no distinct method available for diagnosing Alzheimer's or Mild Cognitive Impairment, and their diagnosis needs a combination of different methods and assessments.

    Methods: Our goal in this study was to evaluate the effectiveness of fMRI imaging in differentiating between Alzheimer's, Mild Cognitive Impairment (MCI and Healthy Aging. To prove fMRI's ability, we compared resting-state brain activation patterns between these three groups of subjects using Independent Component Algorithm (ICA. We examined 40 age- and sex-matched subjects, 15 elderly, 11 MCI and 14 Alzheimer's subjects.

    Results: The results show that during a certain resting-state session, healthy aging brain benefits from larger area and greater intensity of activation (compared with MCI and Alzheimer's group in Posterior Cingulate Cortex (PCC region of the brain, as part of Default Mode Network.

    Conclusion: This difference in activation pattern can be used as a diagnostic criterion in using fMRI for differentiating between Alzheimer's disease (AD, MCI and Healthy Aging.


    Keywords: fMRI, Default Mode Network, Alzheimer's, Mild Cognitive Impairment, Resting-State

  19. Hepatic adenomatosis: rapid sequence MR imaging following gadolinium enhancement: a case report

    Energy Technology Data Exchange (ETDEWEB)

    Brummett, D. [Dept. of Radiology, Medical College of Georgia, Augusta (United States); Burton, E.M. [Dept. of Radiology, Medical College of Georgia, Augusta (United States)]|[Dept. of Pediatrics, Medical College of Georgia, Augusta (United States); Sabio, H. [Dept. of Pediatrics, Medical College of Georgia, Augusta (United States)

    1999-04-01

    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.) With 3 figs., 10 refs.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Body images of patients with anorexia nervosa, bulimia nervosa and female control subjects: a comparison with male ideals of female attractiveness.

    Science.gov (United States)

    Benninghoven, Dieter; Raykowski, Lena; Solzbacher, Svenja; Kunzendorf, Sebastian; Jantschek, Günter

    2007-03-01

    Body images of female patients with anorexia nervosa and bulimia nervosa were assessed against females without eating disorders and compared with male ideals of female attractiveness. A computer program was applied to examine body images of 62 patients with anorexia nervosa, 45 patients with bulimia nervosa, and 40 female and 39 male control subjects. Body size overestimation was most distinct in the two patient groups. Self-ideal discrepancy was highest in bulimia nervosa. Estimation of the society's ideal female body in all three female groups did not differ from men's perception of the most attractive female body. Congruence of ideals of female attractiveness in patients, female, and male control subjects and described differences between patients and female controls support the theory that body image disturbance is a problem of processing self-referential information regarding body image rather than a problem of processing body image related information per se.

  5. 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.

  6. 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

  7. 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

    Nondestructive studies of physiological processes in agronomic products require increasingly higher spatial and temporal resolutions. Nuclear Magnetic Resonance (NMR) imaging is a non-invasive technique providing physiological and morphological information on biological tissues. The aim of this s......Nondestructive studies of physiological processes in agronomic products require increasingly higher spatial and temporal resolutions. Nuclear Magnetic Resonance (NMR) imaging is a non-invasive technique providing physiological and morphological information on biological tissues. The aim...... of columella and in the seed envelopes. The total quantities and the average volume flow of water estimated are: 198 mg, 1.76 mm 3/h for the columella and 326 mg, 2.91 mm 3/h for the seed envelopes. We demonstrate in this paper that the NMR imaging technique coupled with efficient and biocompatible CA...

  8. Fire detection system using random forest classification for image sequences of complex background

    Science.gov (United States)

    Kim, Onecue; Kang, Dong-Joong

    2013-06-01

    We present a fire alarm system based on image processing that detects fire accidents in various environments. To reduce false alarms that frequently appeared in earlier systems, we combined image features including color, motion, and blinking information. We specifically define the color conditions of fires in hue, saturation and value, and RGB color space. Fire features are represented as intensity variation, color mean and variance, motion, and image differences. Moreover, blinking fire features are modeled by using crossing patches. We propose an algorithm that classifies patches into fire or nonfire areas by using random forest supervised learning. We design an embedded surveillance device made with acrylonitrile butadiene styrene housing for stable fire detection in outdoor environments. The experimental results show that our algorithm works robustly in complex environments and is able to detect fires in real time.

  9. 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

    This paper discusses options for testing correspondence algorithms in stereo or motion analysis that are designed or considered for vision-based driver assistance. It introduces a globally available database, with a main focus on testing on video sequences of real-world data. We suggest...... 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......) for demonstrating ideas, difficulties, and possible ways in this future field of extensive performance tests in vision-based driver assistance, particularly for cases where the ground truth is not available. This paper shows that the complexity of real-world data does not support the identification of general...

  10. 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.

  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. 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

    , Pyrenophora, Epicoccum, Didymella, Alternaria, Bipolaris and Microdochium. The fungal composition and quantities on each seed varied significantly. Some were infected mainly by a single fungus and some were infected by multiple fungi. All seeds were prior to this evaluated by multispectral imaging...

  14. MR imaging after rotator cuff repair: full-thickness defects and bursitis-like subacromial abnormalities in asymptomatic subjects.

    Science.gov (United States)

    Zanetti, M; Jost, B; Hodler, J; Gerber, C

    2000-06-01

    To determine the prevalence and extent of residual defects or retears and bursitis-like subacromial abnormalities on MR images after rotator cuff repair in asymptomatic subjects, and to define the clinical relevance of these findings. Fourteen completely asymptomatic patients and 32 patients with residual symptoms were investigated 27-53 months (mean 39 months) after open transosseous reinsertion of the rotator cuff. Coronal T2-weighted turbo spin-echo and turbo STIR or T2-weighted fat-suppressed MR images were obtained. The prevalence and extent of residual defects or retears of the rotator cuff and bursitis-like subacromial abnormalities were determined. Residual defects or retears were detected in three (21%) and bursitis-like abnormalities in 14 (100%) of the 14 asymptomatic patients. Fifteen (47%) residual defects or retears and 31 (97%) bursitis-like abnormalities were diagnosed in the 32 patients with residual symptoms. The size of the residual defects/retears was significantly smaller in the asymptomatic group (mean 8 mm, range 6-11 mm) than in the symptomatic group (mean 32 mm, range 7-50 mm) (t-test, P = 0.001). The extent of the bursitis-like subacromial abnormalities did not significantly differ (t-test, P > 0.05) between asymptomatic (mean 28 x 3 mm) and symptomatic patients (mean 32 x 3 mm). Small residual defects or retears (Subacromial bursitis-like MR abnormalities are almost always seen after rotator cuff repair even in patients without residual complaints. They may persist for several years after rotator cuff repair and appear to be clinically irrelevant.

  15. MR imaging after rotator cuff repair: full-thickness defects and bursitis-like subacromial abnormalities in asymptomatic subjects

    Energy Technology Data Exchange (ETDEWEB)

    Zanetti, M.; Hodler, J. [Dept. of Radiology, University Hospital Balgrist, Zurich (Switzerland); Jost, B.; Gerber, C. [Dept. of Orthopedic Surgery, University Hospital Balgrist, Zurich (Switzerland)

    2000-06-01

    Objective. To determine the prevalence and extent of residual defects or retears and bursitis-like subacromial abnormalities on MR images after rotator cuff repair in asymptomatic subjects, and to define the clinical relevance of these findings.Design and patients. Fourteen completely asymptomatic patients and 32 patients with residual symptoms were investigated 27-53 months (mean 39 months) after open transosseous reinsertion of the rotator cuff. Coronal T2-weighted turbo spin-echo and turbo STIR or T2-weighted fat-suppressed MR images were obtained. The prevalence and extent of residual defects or retears of the rotator cuff and bursitis-like subacromial abnormalities were determined.Results. Residual defects or retears were detected in three (21%) and bursitis-like abnormalities in 14 (100%) of the 14 asymptomatic patients. Fifteen (47%) residual defects or retears and 31 (97%) bursitis-like abnormalities were diagnosed in the 32 patients with residual symptoms. The size of the residual defects/retears was significantly smaller in the asymptomatic group (mean 8 mm, range 6-11 mm) than in the symptomatic group (mean 32 mm, range 7-50 mm) (t-test, P=0.001). The extent of the bursitis-like subacromial abnormalities did not significantly differ (t-test, P>0.05) between asymptomatic (mean 28 x 3 mm) and symptomatic patients (mean 32 x 3 mm).Conclusion. Small residual defects or retears (<1 cm) of the rotator cuff are not necessarily associated with clinical symptoms. Subacromial bursitis-like MR abnormalities are almost always seen after rotator cuff repair even in patients without residual complaints. They may persist for several years after rotator cuff repair and appear to be clinically irrelevant. (orig.)

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

    Science.gov (United States)

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

    2014-07-01

    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. 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. 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 contour distance 1.37 ± 0

  17. Magnetic resonance imaging of solid dental restoration materials using 3D UTE sequences: visualization and relaxometry of various compounds.

    Science.gov (United States)

    Grosse, Ulrich; Syha, Roland; Papanikolaou, Dimitrios; Martirosian, Petros; Grözinger, Gerd; Schabel, Christoph; Schick, Fritz; Springer, Fabian

    2013-12-01

    Due to an increasing scientific interest in MR-imaging of carious lesions and teeth, an accurate signal characterization of dental restoration materials is necessary for optimization of MR sequence protocols and evaluation of material degradation. Therefore, signal yield and relaxation behavior of common dental restoration materials in comparison to those of dentine of extracted human teeth were assessed in vitro by ultrashort echo time (UTE) sequences. Eighteen material samples and dentine of two freshly extracted human teeth were investigated on a 3T whole-body clinical MR-scanner. Transverse (T2*) and longitudinal relaxation times (T1) were quantified using a recently published modified Ernst equation that takes relevant in-pulse relaxation effects into account. All investigated samples could be successfully visualized but maximum signal yield was highly variable between samples. T1-values of the investigated dental restoration materials ranged between 28 and 365 ms, whereas T2*-values ranged between 96 and 917 μs. In contrast, T1-values of dentine (T1=545 ms±299 ms) were higher, while T2*-values (T2*=478 μs±271 μs) showed similar values. Dental restoration materials and dentine of extracted human teeth can be visualized by UTE sequences and show a broad range of signal yield and relaxation times.

  18. 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.

  19. Prognostic value of gradient echo T2* sequences for brain MR imaging in preterm infants.

    Science.gov (United States)

    de Bruïne, Francisca T; Steggerda, Sylke J; van den Berg-Huysmans, Annette A; Leijser, Lara M; Rijken, Monique; van Buchem, Mark A; van Wezel-Meijler, Gerda; van der Grond, Jeroen

    2014-03-01

    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 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 hemosiderin deposits is limited as there is no independent association with neurodevelopmental outcome.

  20. 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

  1. 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

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

    Science.gov (United States)

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

    2017-07-01

    The open-source and cross-platform software CycloBranch was utilized for dereplication of organic compounds from mass spectrometry imaging imzML datasets and its functions were illustrated on microbial siderophores. The pixel-to-pixel batch-processing was analogous to liquid chromatography mass spectrometry data. Each data point represented here by accurate m/z values and the corresponding ion intensities was matched against integrated compound libraries. The fine isotopic structure matching was also embedded into CycloBranch dereplication process. The siderophores' characterization from single-pixel mass spectra was further supported by their de novo sequencing. New ketide building block library was utilized by CycloBranch to characterize the siderophores in images and mixtures and nomenclature of fragment ion series of linear and cyclic polyketide siderophores was proposed. The software is freely available at http://ms.biomed.cas.cz/cyclobranch. 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.

  3. Intraindividual evaluation of the influence of iterative reconstruction and filter kernel on subjective and objective image quality in computed tomography of the brain

    Energy Technology Data Exchange (ETDEWEB)

    Buhk, J.H. [Univ. Medical Center, Hamburg-Eppendorf (Germany). Dept. of Neuroradiology; Laqmani, A.; Schultzendorff, H.C. von; Hammerle, D.; Adam, G.; Regier, M. [Univ. Medical Center, Hamburg-Eppendorf (Germany). Dept. of Diagnostic and Interventional Radiology; Sehner, S. [Univ. Medical Center, Hamburg-Eppendorf (Germany). Inst. of Medical Biometry and Epidemiology; Fiehler, J. [Univ. Medical Center, Hamburg-Eppendorf (Germany). Neuroradiology; Nagel, H.D. [Dr. HD Nagel, Science and Technology for Radiology, Buchholz (Germany)

    2013-08-15

    Objectives: To intraindividually evaluate the potential of 4th generation iterative reconstruction (IR) on brain CT with regard to subjective and objective image quality. Methods: 31 consecutive raw data sets of clinical routine native sequential brain CT scans were reconstructed with IR level 0 (= filtered back projection), 1, 3 and 4; 3 different brain filter kernels (smooth/standard/sharp) were applied respectively. Five independent radiologists with different levels of experience performed subjective image rating. Detailed ROI analysis of image contrast and noise was performed. Statistical analysis was carried out by applying a random intercept model. Results: Subjective scores for the smooth and the standard kernels were best at low IR levels, but both, in particular the smooth kernel, scored inferior with an increasing IR level. The sharp kernel scored lowest at IR 0, while the scores substantially increased at high IR levels, reaching significantly best scores at IR 4. Objective measurements revealed an overall increase in contrast-to-noise ratio at higher IR levels, which was highest when applying the soft filter kernel. The absolute grey-white contrast decreased with an increasing IR level and was highest when applying the sharp filter kernel. All subjective effects were independent of the raters' experience and the patients' age and sex. Conclusion: Different combinations of IR level and filter kernel substantially influence subjective and objective image quality of brain CT. (orig.)

  4. Two Algorithms for the Detection and Tracking of Moving Vehicle Targets in Aerial Infrared Image Sequences

    Directory of Open Access Journals (Sweden)

    Yutian Cao

    2015-12-01

    Full Text Available In this paper, by analyzing the characteristics of infrared moving targets, a Symmetric Frame Differencing Target Detection algorithm based on local clustering segmentation is proposed. In consideration of the high real-time performance and accuracy of traditional symmetric differencing, this novel algorithm uses local grayscale clustering to accomplish target detection after carrying out symmetric frame differencing to locate the regions of change. In addition, the mean shift tracking algorithm is also improved to solve the problem of missed targets caused by error convergence. As a result, a kernel-based mean shift target tracking algorithm based on detection updates is also proposed. This tracking algorithm makes use of the interaction between detection and tracking to correct the tracking errors in real time and to realize robust target tracking in complex scenes. In addition, the validity, robustness and stability of the proposed algorithms are all verified by experiments on mid-infrared aerial sequences with vehicles as targets.

  5. Correcting dynamic distortions in 7T echo planar imaging using a jittered echo time sequence

    Science.gov (United States)

    Dymerska, Barbara; Poser, Benedikt A.; Bogner, Wolfgang; Visser, Eelke; Eckstein, Korbinian; Cardoso, Pedro; Barth, Markus; Trattnig, Siegfried

    2015-01-01

    Purpose To develop a distortion correction method for echo planar imaging (EPI) that is able to measure dynamic changes in B0. Theory and Methods The approach we propose is based on single‐echo EPI with a jittering of the echo time between two values for alternate time points. Field maps are calculated between phase images from adjacent volumes and are used to remove distortion from corresponding magnitude images. The performance of our approach was optimized using an analytical model and by comparison with field maps from dual‐echo EPI. The method was tested in functional MRI experiments at 7T with motor tasks and compared with the conventional static approach. Results Unwarping using our method was accurate even for head rotations up to 8.2°, where the static approach introduced errors up to 8.2 mm. Jittering the echo time between 19 and 25 ms had no measurable effect on blood oxygenation level–dependent (BOLD) sensitivity. Our approach reduced the distortions in activated regions to distortion correction in the presence of motion. No reduction in BOLD sensitivity was observed. As such, it is suitable for application in a wide range of functional MRI experiments. Magn Reson Med 76:1388–1399, 2016. © 2015 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 License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. PMID:26584148

  6. 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.)

  7. 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.

  8. Magnetic resonance imaging determined visceral fat reduction associates with enhanced IL-10 plasma levels in calorie restricted obese subjects.

    Directory of Open Access Journals (Sweden)

    Gloria Formoso

    Full Text Available BACKGROUND: Obesity is characterized by a low grade chronic inflammation state. Indeed circulating pro-inflammatory cytokines, such as TNF-α and IL-6, are elevated in obese subjects, while anti-inflammatory cytokines, such as IL-10, appear to be reduced. Cytokines profile improves after weight loss, but how visceral or subcutaneous fat loss respectively affect pro- or anti-inflammatory cytokines plasma levels has not been precisely assessed. Therefore in the present study we correlated changes in circulating cytokine profile with quantitative changes in visceral and subcutaneous adipose tissue depots measured by an ad hoc Magnetic Resonance Imaging (MRI protocol before and after weight loss. MATERIALS AND METHODS: In 14 obese subjects, MRI determination of visceral and subcutaneous fat and plasma glucose, insulin, TNF-α IL-6, and IL-10 measurements were performed before and after a caloric restriction induced weight loss of at least 5% of the original body weight. RESULTS: Weight loss improved insulin sensitivity (QUICKI Index: 0.35±0.03 vs 0.37±0.04; P<0.05, increased IL-10 (3.4±1.9 vs 4.6±1.0 pg/mL; P<0.03, and reduced TNF-α and IL-6 plasma levels (2.5±1.3 vs 1.6±1.5 pg/mL, P<0.0015, 2.3±0.4 vs 1.6±0.6 pg/mL, P<0.02 respectively. A significant correlation was observed between the amount of visceral fat loss and the percentage reduction in both TNF-α (r = 0.56, p<0.05 and IL-6 (r = 0.19 p<0.05 plasma levels. In a multiple regression analysis, the amount of visceral fat loss independently correlated with the increase in IL-10 plasma levels. CONCLUSION: The reduction in visceral adipose tissue is the main driver of the improved inflammatory profile induced by weight loss.

  9. Radiologically defining horizontal gaze using EOS imaging-a prospective study of healthy subjects and a retrospective audit.

    Science.gov (United States)

    Hey, Hwee Weng Dennis; Tan, Kimberly-Anne; Ho, Vivienne Chien-Lin; Azhar, Syifa Bte; Lim, Joel-Louis; Liu, Gabriel Ka-Po; Wong, Hee-Kit

    2017-10-18

    +D yielded compliance rates of 76.7%, a figure much closer to that of A+B+C+D (74.8%). From a practical viewpoint, Criterion B+D were most suitable for clinical use and could be simplified to the "3-6-12 rule" as a form of cursory assessment. Verbal instructions in the absence of stringent postural checks only ensured that ~75% of subjects achieved horizontal gaze. Fulfillment of Criterion B+D is sufficient to evaluate for horizontal gaze. Further criteria can be added to increase sensitivity. Verbal instructions alone yield high rates of inaccuracy when attempting to image patients in horizontal gaze. Apart from improving methods for obtaining radiographs, a radiological definition of horizontal gaze should be routinely applied for better evaluation of sagittal spinal alignment. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Improved Detection of Kidney Stones Using an Optimized Doppler Imaging Sequence

    Science.gov (United States)

    Cunitz, Bryan; Dunmire, Barbrina; Paun, Marla; Sapozhnikov, Oleg; Kucewicz, John; Hsi, Ryan; Lee, Franklin; Sorensen, Matthew; Harper, Jonathan; Bailey, Michael

    2015-01-01

    Kidney stones have been shown to exhibit a “twinkling artifact” (TA) under Color-Doppler ultrasound. Although this technique has better specificity than conventional Bmode imaging, it has lower sensitivity. To improve the overall performance of using TA as a diagnostic tool, Doppler output parameters were optimized in-vitro. The collected data supports a previous hypothesis that TA is caused by random oscillations of micron sized bubbles trapped in the cracks and crevices of kidney stones. A set of optimized parameters were implemented such that that the MI & TI remained within the FDA approved limits. Several clinical kidney scans were performed with the optimized settings and were able to detect stones with improved SNR relative to the default settings. PMID:26203346

  11. Mapping of cortical language function by functional magnetic resonance imaging and repetitive navigated transcranial magnetic stimulation in 40 healthy subjects.

    Science.gov (United States)

    Sollmann, Nico; Ille, Sebastian; Boeckh-Behrens, Tobias; Ringel, Florian; Meyer, Bernhard; Krieg, Sandro M

    2016-07-01

    Functional magnetic resonance imaging (fMRI) is considered to be the standard method regarding non-invasive language mapping. However, repetitive navigated transcranial magnetic stimulation (rTMS) gains increasing importance with respect to that purpose. However, comparisons between both methods are sparse. We performed fMRI and rTMS language mapping of the left hemisphere in 40 healthy, right-handed subjects in combination with the tasks that are most commonly used in the neurosurgical context (fMRI: word-generation = WGEN task; rTMS: object-naming = ON task). Different rTMS error rate thresholds (ERTs) were calculated, and Cohen's kappa coefficient and the cortical parcellation system (CPS) were used for systematic comparison of the two techniques. Overall, mean kappa coefficients were low, revealing no distinct agreement. We found the highest agreement for both techniques when using the 2-out-of-3 rule (CPS region defined as language positive in terms of rTMS if at least 2 out of 3 stimulations led to a naming error). However, kappa for this threshold was only 0.24 (kappa of <0, 0.01-0.20, 0.21-0.40, 0.41-0.60, 0.61-0.80 and 0.81-0.99 indicate less than chance, slight, fair, moderate, substantial and almost perfect agreement, respectively). Because of the inherent differences in the underlying physiology of fMRI and rTMS, the different tasks used and the impossibility of verifying the results via direct cortical stimulation (DCS) in the population of healthy volunteers, one must exercise caution in drawing conclusions about the relative usefulness of each technique for language mapping. Nevertheless, this study yields valuable insights into these two mapping techniques for the most common language tasks currently used in neurosurgical practice.

  12. Characteristics of subjective recognition and computer-aided image analysis of facial erythematous skin diseases: a cornerstone of automated diagnosis.

    Science.gov (United States)

    Choi, J W; Kim, B R; Lee, H S; Youn, S W

    2014-08-01

    Rosacea and seborrhoeic dermatitis are common diseases that cause facial erythema. They have common features and are frequently misdiagnosed. To extract characteristic features of erythrotelangiectatic rosacea (ETR), papulopustular rosacea (PPR) and seborrhoeic dermatitis (SEB) through computer-aided image analysis (CAIA) and compare them with subjectively recognized features and to use these findings to construct a decision tree for differential diagnosis. Thirty-four clinical photos of patients with facial erythema were assessed: 12 patients were classified as showing ETR, 12 as PPR and 10 as SEB. Five dermatologists blinded to the original diagnosis gave their impressions of each photo. The mean, SD and T-zone to U-zone (T/U) ratios of the erythema parameter a* (a* of the L*a*b* colour space) were calculated for each photo using CAIA. These CAIA parameters were compared between impression groups. The most closely related CAIA parameter for each disease was established using the receiver-operating characteristic curve analysis. A decision tree which predicts the diagnosis from given CAIA parameters was constructed. All the photos classified as PPR generated impressions of PPR. However, approximately 30% of the photos classified as ETR generated impressions of SEB and vice versa. PPR was characterized by a large SD of erythema of the cheek, ETR was characterized by a large mean erythema of the U-zone, and SEB was characterized by a large T/U ratio of mean erythema. Fifteen additional photos were examined: the decision tree predicted the original diagnosis for 14, but incorrectly predicted one case of ETR as SEB. The CAIA result of facial erythema is well correlated with the actual clinical diagnosis. The accuracy of differential diagnosis using a decision tree with CAIA parameters is as good as that of global examination impressions of dermatologists. © 2013 British Association of Dermatologists.

  13. Aeromonas salmonicida - Epidemiology, whole genome sequencing, detection and in vivo imaging

    DEFF Research Database (Denmark)

    Bartkova, Simona

    effects. Antibiotics are therefore used as treatment, which due to the possibility of developing resistance is neither a favorable nor sustainable solution. To complicate things further, it is possible that fish can be carriers of A. salmonicida and transfer the bacterium from freshwater to the sea where...... 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...... and then examined for presence of plasmids, virulence and iron acquisition proteins, and antibiotic resistance genes. The chromosome was also examined for single nucleotide polymorphisms that were aligned and subjected to Bayesian temporal tree reconstruction using the published genome of A. salmonicida A449...

  14. Comparison of spoiled gradient echo and steady-state free-precession imaging for native myocardial T1 mapping using the slice-interleaved T1 mapping (STONE) sequence.

    Science.gov (United States)

    Jang, Jihye; Bellm, Steven; Roujol, Sébastien; Basha, Tamer A; Nezafat, Maryam; Kato, Shingo; Weingärtner, Sebastian; Nezafat, Reza

    2016-10-01

    Cardiac T1 mapping allows non-invasive imaging of interstitial diffuse fibrosis. Myocardial T1 is commonly calculated by voxel-wise fitting of the images acquired using balanced steady-state free precession (SSFP) after an inversion pulse. However, SSFP imaging is sensitive to B1 and B0 imperfection, which may result in additional artifacts. A gradient echo (GRE) imaging sequence has been used for myocardial T1 mapping; however, its use has been limited to higher magnetic field to compensate for the lower signal-to-noise ratio (SNR) of GRE versus SSFP imaging. A slice-interleaved T1 mapping (STONE) sequence with SSFP readout (STONE-SSFP) has been recently proposed for native myocardial T1 mapping, which allows longer recovery of magnetization (>8 R-R) after each inversion pulse. In this study, we hypothesize that a longer recovery allows higher SNR and enables native myocardial T1 mapping using STONE with GRE imaging readout (STONE-GRE) at 1.5T. Numerical simulations and phantom and in vivo imaging were performed to compare the performance of STONE-GRE and STONE-SSFP for native myocardial T1 mapping at 1.5T. In numerical simulations, STONE-SSFP shows sensitivity to both T2 and off resonance. Despite the insensitivity of GRE imaging to T2 , STONE-GRE remains sensitive to T2 due to the dependence of the inversion pulse performance on T2 . In the phantom study, STONE-GRE had inferior accuracy and precision and similar repeatability as compared with STONE-SSFP. In in vivo studies, STONE-GRE and STONE-SSFP had similar myocardial native T1 times, precisions, repeatabilities and subjective T1 map qualities. Despite the lower SNR of the GRE imaging readout compared with SSFP, STONE-GRE provides similar native myocardial T1 measurements, precision, repeatability, and subjective image quality when compared with STONE-SSFP at 1.5T. Copyright © 2016 John Wiley & Sons, Ltd.

  15. Chunking during human visuomotor sequence learning.

    Science.gov (United States)

    Sakai, Katsuyuki; Kitaguchi, Katsuya; Hikosaka, Okihide

    2003-09-01

    Motor sequence learning is a process whereby a series of elementary movements is re-coded into an efficient representation for the entire sequence. Here we show that human subjects learn a visuomotor sequence by spontaneously chunking the elementary movements, while each chunk acts as a single memory unit. The subjects learned to press a sequence of 10 sets of two buttons through trial and error. By examining the temporal patterns with which subjects performed a visuomotor sequence, we found that the subjects performed the 10 sets as several clusters of sets, which were separated by long time gaps. While the overall performance time decreased by repeating the same sequence, the clusters became clearer and more consistent. The cluster pattern was uncorrelated with the distance of hand movements and was different across subjects who learned the same sequence. We then split a learned sequence into three segments, while preserving or destroying the clusters in the learned sequence, and shuffled the segments. The performance on the shuffled sequence was more accurate and quicker when the clusters in the original sequence were preserved than when they were destroyed. The results suggest that each cluster is processed as a single memory unit, a chunk, and is necessary for efficient sequence processing. A learned visuomotor sequence is hierarchically represented as chunks that contain several elementary movements. We also found that the temporal patterns of sequence performance transferred from the nondominant to dominant hand, but not vice versa. This may suggest a role of the dominant hemisphere in storage of learned chunks. Together with our previous unit-recording and imaging studies that used the same learning paradigm, we predict specific roles of the dominant parietal area, basal ganglia, and presupplementary motor area in the chunking.

  16. 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

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

    Science.gov (United States)

    van Nierop, Bastiaan J; Bax, Noortje A M; Nelissen, Jules L; Arslan, Fatih; Motaal, Abdallah G; de Graaf, Larry; Zwanenburg, Jaco J M; Luijten, Peter R; Nicolay, Klaas; Strijkers, Gustav J

    2015-01-01

    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

  18. Comparison of dual-energy X-ray absorptiometry and magnetic resonance imaging-measured adipose tissue depots in HIV-infected and control subjects.

    Science.gov (United States)

    Scherzer, Rebecca; Shen, Wei; Bacchetti, Peter; Kotler, Donald; Lewis, Cora E; Shlipak, Michael G; Punyanitya, Mark; Heymsfield, Steven B; Grunfeld, Carl

    2008-10-01

    Studies in persons without HIV infection have compared adipose tissue measured by dual-energy X-ray absorptiometry (DXA) and magnetic resonance imaging (MRI), but no such study has been conducted in HIV-infected (HIV+) subjects, who have a high prevalence of regional fat loss. We compared DXA- with MRI-measured trunk, leg, arm, and total fat in HIV+ and control subjects. A cross-sectional analysis was conducted in 877 HIV+ subjects and 260 control subjects in FRAM (Study of Fat Redistribution and Metabolic Change in HIV Infection), stratified by sex and HIV status. Univariate associations of DXA with MRI were strongest for total and trunk fat (r > or = 0.92) and slightly weaker for leg (r > or = 0.87) and arm (r > or = 0.71) fat. The average estimated limb fat was substantially greater for DXA than for MRI for HIV+ and control men and women (all P < 0.0001). Less of a difference was observed in trunk fat measured by DXA and MRI, but the difference was still statistically significant (P < 0.0001). Bland-Altman plots showed increasing differences and variability. Greater average limb fat in control and HIV+ subjects (both P < 0.0001) was associated with greater differences between DXA and MRI measurements. Because the control subjects had more limb fat than did the HIV+ subjects, greater amounts of fat were measured by DXA than by MRI when control subjects were compared with HIV+ subjects. More HIV+ subjects had leg fat in the bottom decile of the control subjects by DXA than by MRI (P < 0.0001). Although DXA- and MRI-measured adipose tissue depots correlate strongly in HIV+ and control subjects, differences increase as average fat increases, particularly for limb fat. DXA may estimate a higher prevalence of peripheral lipoatrophy than does MRI in HIV+ subjects.

  19. 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.

  20. Using optical full-field measurement based on digital image correlation to measure strain on a tree subjected to mechanical load

    Czech Academy of Sciences Publication Activity Database

    Sebera, V.; Praus, L.; Tippner, J.; Kunecký, Jiří; Čepela, J.; Wimmer, R.

    2014-01-01

    Roč. 28, č. 4 (2014), s. 1173-1184 ISSN 0931-1890 Institutional support: RVO:68378297 Keywords : digital image correlation * tree biomechanics * strain * pulling test * arboriculture * nondestructive Subject RIV: JJ - Other Materials Impact factor: 1.651, year: 2014

  1. The temporal sequence of gut peptide CNS interactions tracked in vivo by magnetic resonance imaging.

    Science.gov (United States)

    Kuo, Yu-Ting; Parkinson, James R C; Chaudhri, Owais B; Herlihy, Amy H; So, Po-Wah; Dhillo, Waljit S; Small, Caroline J; Bloom, Stephen R; Bell, Jimmy D

    2007-11-07

    Hormonal satiety signals secreted by the gut play a pivotal role in the physiological control of appetite. However, therapeutic exploitation of the gut-brain axis requires greater insight into the interaction of gut hormones with CNS circuits of appetite control. Using the manganese ion (Mn2+) as an activity-dependent magnetic resonance imaging (MRI) contrast agent, we showed an increase in signal intensity (SI) in key appetite-regulatory regions of the hypothalamus, including the arcuate, paraventricular, and ventromedial nuclei, after peripheral injection of the orexigenic peptide ghrelin. Conversely, administration of the anorexigenic hormone peptide YY(3-36) caused a reduction in SI. In both cases, the changes in SI recorded in the hypothalamic arcuate nucleus preceded the effect of these peptides on food intake. Intravenous Mn2+ itself did not significantly alter ghrelin-mediated expression of the immediate early gene product c-Fos, nor did it cause abnormalities of behavior or metabolic parameters. We conclude that manganese-enhanced MRI constitutes a powerful tool for the future investigation of the effects of drugs, hormones, and environmental influences on neuronal activity.

  2. 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%.

  3. Improvement of water saturation shift referencing by sequence and analysis optimization to enhance chemical exchange saturation transfer imaging.

    Science.gov (United States)

    Müller-Lutz, Anja; Matuschke, Felix; Schleich, Christoph; Wickrath, Frithjof; Boos, Johannes; Schmitt, Benjamin; Wittsack, Hans-Jörg

    2016-07-01

    To optimize B0-field inhomogeneity correction for chemical exchange saturation transfer (CEST) imaging by investigating different water saturation shift referencing (WASSR) Z-spectrum shapes and different frequency correction techniques. WASSR Z-spectra were simulated for different B1-fields and pulse durations (PD). Two parameter settings were used for further simulations and experiments (WASSR1: B1=0.1 μT, PD=50ms; WASSR2: B1=0.3 μT, PD=40ms). Four frequency correction techniques were investigated: 1) MinW: Minimum of the spline-interpolated WASSR-spectrum; 2) MSCF: maximum symmetry center frequency algorithm; 3) PMSCF: further development of MSCF algorithm; 4) BFit: fit with Bloch equations. Performance of frequency correction was assessed with Monte-Carlo simulations and in-vivo MR examinations in the brain and intervertebral disks. Different shapes of WASSR-Z-spectra were obtained by changing B1 and PD including spectra with one (1-Peak) or two (2-Peak) minima. WASSR1 resulted in 1-Peak WASSR-spectrum, whereas WASSR2 resulted in 2-Peak WASSR-spectrum. Both Monte-Carlo simulations and in-vivo MR examinations revealed highest accuracy of field-inhomogeneity correction with WASSR1 combined with PMSCF or BFit. Using a WASSR sequence, which results in a Z-spectrum with a single absorption peak, in combination with advanced postprocessing algorithms enables improved B0-field inhomogeneity correction for CEST imaging. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Automatically Identifying Fusion Events between GLUT4 Storage Vesicles and the Plasma Membrane in TIRF Microscopy Image Sequences.

    Science.gov (United States)

    Wu, Jian; Xu, Yingke; Feng, Zhouyan; Zheng, Xiaoxiang

    2015-01-01

    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.

  5. 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.

  6. An automated image-based method of 3D subject-specific body segment parameter estimation for kinetic analyses of rapid movements.

    Science.gov (United States)

    Sheets, Alison L; Corazza, Stefano; Andriacchi, Thomas P

    2010-01-01

    Accurate subject-specific body segment parameters (BSPs) are necessary to perform kinetic analyses of human movements with large accelerations, or no external contact forces or moments. A new automated topographical image-based method of estimating segment mass, center of mass (CM) position, and moments of inertia is presented. Body geometry and volume were measured using a laser scanner, then an automated pose and shape registration algorithm segmented the scanned body surface, and identified joint center (JC) positions. Assuming the constant segment densities of Dempster, thigh and shank masses, CM locations, and moments of inertia were estimated for four male subjects with body mass indexes (BMIs) of 19.7-38.2. The subject-specific BSP were compared with those determined using Dempster and Clauser regression equations. The influence of BSP and BMI differences on knee and hip net forces and moments during a running swing phase were quantified for the subjects with the smallest and largest BMIs. Subject-specific BSP for 15 body segments were quickly calculated using the image-based method, and total subject masses were overestimated by 1.7-2.9%.When compared with the Dempster and Clauser methods, image-based and regression estimated thigh BSP varied more than the shank parameters. Thigh masses and hip JC to thigh CM distances were consistently larger, and each transverse moment of inertia was smaller using the image-based method. Because the shank had larger linear and angular accelerations than the thigh during the running swing phase, shank BSP differences had a larger effect on calculated intersegmental forces and moments at the knee joint than thigh BSP differences did at the hip. It was the net knee kinetic differences caused by the shank BSP differences that were the largest contributors to the hip variations. Finally, BSP differences produced larger kinetic differences for the subject with larger segment masses, suggesting that parameter accuracy is more

  7. Visual perception of spatial subjects

    Energy Technology Data Exchange (ETDEWEB)

    Osterloh, K.R.S.; Ewert, U. [Federal Institute for Materials Research and Testing (BAM), Berlin (Germany)

    2007-07-01

    Principally, any imaging technology consists of two consecutive, though strictly separated processes: data acquisition and subsequent processing to generate an image that can be looked at, either on a monitor screen or printed on paper. Likewise, the physiological process of viewing can be separated into vision and perception, though these processes are much more overlapping. Understanding the appearance of a subject requires the entire sequence from receiving the information carried e.g. by photons up to an appropriate processing leading to the perception of the subject shown. As a consequence, the imagination of a subject is a result of both, technological and physiological processes. Whenever an evaluation of an image is critical, also the physiological part of the processing should be considered. However, an image has two dimensions in the first place and reality is spatial, it has three dimensions. This problem has been tackled on a philosophical level at least since Platon's famous discussion on the shadow image in a dark cave. The mere practical point is which structural details can be perceived and what may remain undetected depending on the mode of presentation. This problem cannot be resolved without considering each single step of visual perception. Physiologically, there are three 'tools' available to understanding the spatial structure of a subject: binocular viewing, following the course of perspective projection and motion to collect multiple aspects. Artificially, an object may be cut in various ways to display the interior or covering parts could be made transparent within a model. Samples will be shown how certain details of a subject can be emphasised or hidden depending on the way of presentation. It needs to be discussed what might help to perceive the true spatial structure of a subject with all relevant details and what could be misleading. (authors)

  8. Imaging neonates and children with Pierre Robin sequence before and after mandibular distraction osteogenesis: what the craniofacial surgeon wants to know

    Energy Technology Data Exchange (ETDEWEB)

    Meyers, Arthur B. [Children' s Hospital of Wisconsin, Department of Imaging, Medical College of Wisconsin, P.O. Box 1997, Milwaukee, WI (United States); Zei, Markus G. [Medical College of Wisconsin, Milwaukee, WI (United States); St. Louis University School of Medicine, St. Louis, MO (United States); Denny, Arlen D. [Children' s Hospital of Wisconsin, Department of Plastic Surgery, Medical College of Wisconsin, Milwaukee, WI (United States)

    2015-08-15

    Pierre Robin sequence is characterized by micrognathia and glossoptosis causing upper airway obstruction. Mandibular distraction osteogenesis is a mandibular lengthening procedure performed in neonates and children with Pierre Robin sequence to alleviate airway compromise. This pictorial review demonstrates the role of imaging in the preoperative and postoperative assessment of these children. It is important for pediatric radiologists to know what information about the mandible and airway the craniofacial surgeon needs from preoperative imaging and to identify any complications these children may encounter after surgery. (orig.)

  9. Imaging gastric structuring of lipid emulsions and its effect on gastrointestinal function: a randomized trial in healthy subjects.

    Science.gov (United States)

    Steingoetter, Andreas; Radovic, Tijana; Buetikofer, Simon; Curcic, Jelena; Menne, Dieter; Fried, Michael; Schwizer, Werner; Wooster, Tim J

    2015-04-01

    Efficient fat digestion requires fat processing within the stomach and fat sensing in the intestine. Both processes also control gastric emptying and gastrointestinal secretions. We aimed to visualize the influence of the intragastric stability of fat emulsions on their dynamics of gastric processing and structuring and to assess the effect this has on gastrointestinal motor and secretory functions. Eighteen healthy subjects with normal body mass index (BMI) were studied on 4 separate occasions in a double-blind, randomized, crossover design. Magnetic resonance imaging (MRI) data of the gastrointestinal tract and blood triglycerides were recorded before and for 240 min after the consumption of the following 4 different fat emulsions: lipid emulsion 1 (LE1; acid stable, 0.33 μm), lipid emulsion 2 (LE2; acid stable, 52 μm), lipid emulsion 3 (LE3; acid unstable, solid fat, 0.32 μm), and lipid emulsion 4 (LE4; acid unstable, liquid fat, 0.38 μm). Intragastric emulsion instability was associated with a change in gastric emptying. Acid-unstable emulsions exhibited biphasic and faster emptying profiles than did the 2 acid-stable emulsions (P ≤ 0.0001). When combined with solid fat (LE3), different dynamics of postprandial gallbladder volume were induced (P ≤ 0.001). For acid-stable emulsions, a reduction of droplet size by 2 orders of magnitude [LE1 (0.33 μm) compared with LE2 (52 μm)] delayed gastric emptying by 38 min. Although acid-stable (LE1 and LE2) and redispersible (LE4) emulsions caused a constant increase in blood triglycerides, no increase was detectable for LE3 (P emulsions. The acute effects of lipid emulsions on gastric emptying, gallbladder volume, and triglyceride absorption are dependent on microstructural changes undergone during consumption. Gastric peristalsis and secretion were effective at redispersing pools of liquid fat in the stomach. This trial was registered at clinicaltrials.gov as NCT01253005. © 2015 American Society for Nutrition.

  10. Analysis of motion tracking in echocardiographic image sequences: influence of system geometry and point-spread function.

    Science.gov (United States)

    Touil, Basma; Basarab, Adrian; Delachartre, Philippe; Bernard, Olivier; Friboulet, Denis

    2010-03-01

    studies did not consider translation in their experiments, since their simulation model (spatially invariant PSF and linear probe) yields by definition no decorrelation. On the opposite, our realistic simulation settings (i.e., sectorial probe and realistic beamforming) show that translation yields decorrelation, particularly when translation is large (above 6 mm) and when the moving regions is located close to the probe (distance to probe less than 50 mm). The tracking accuracy study shows that tracking errors are larger for the usual cartesian data, whatever the estimation algorithm, indicating that speckle tracking is more reliable when based on the unconverted polar data: for axial translations in the range 0-10 mm, the maximum error associated to conventional block matching (BM) is 4.2 mm when using cartesian data and 1.8 mm for polar data. The corresponding errors are 1.8 mm (cartesian data) and 0.4 mm (polar data) for an applied deformation in the range 0-10%. We also show that accuracy is improved by using the bilinear deformable block matching (BDBM) algorithm. For translation, the maximum error associated to the bilinear deformable block matching is indeed 3.6mm (cartesian data) and 1.2 mm (polar data). Regarding deformation, the error is 0.7 mm (cartesian data) and 0.3 mm (polar data). These figures also indicates that the larger improvement brought by the bilinear deformable block matching over standard block matching logically takes place when deformation on cartesian data is considered (the error drops from 1.8 to 0.7 mm is this case). We give a preliminary evaluation of this framework on a cardiac sequence acquired with a Toshiba Powervision 6000 imaging system using a probe operating at 3.25 MHz. As ground truth reference motion is not available in this case, motion estimation performance was evaluated by comparing a reference image (i.e., the first image of the sequence) and the subsequent images after motion compensation has been applied. The comparison

  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. Reproducibility of fat area measurements in young, non-obese subjects by computerized analysis of magnetic resonance images

    NARCIS (Netherlands)

    Elbers, J.M.; Haumann, G.; Asscheman, H.; Seidell, J C; Gooren, Louis J G

    1997-01-01

    OBJECTIVE: To assess reproducibility, expressed as both inter-observer variability and intra-observer variability, of fat area measurements on images obtained by magnetic resonance (MR); to compare variability between fat area measurements, calculated from a single image per body region and from the

  13. In vivo imaging of palisades of Vogt in dry eye versus normal subjects using en-face spectral-domain optical coherence tomography.

    Directory of Open Access Journals (Sweden)

    Wajdene Ghouali

    Full Text Available To evaluate a possible clinical application of spectral-domain optical coherence tomography (SD-OCT using en-face module for the imaging of the corneoscleral limbus in normal subjects and dry eye patients.Seventy-six subjects were included in this study. Seventy eyes of 35 consecutive patients with dry eye disease and 82 eyes of 41 healthy control subjects were investigated. All subjects were examined with the Avanti RTVue® anterior segment OCT. En-face OCT images of the corneoscleral limbus were acquired in four quadrants (inferior, superior, nasal and temporal and then were analyzed semi-quantitatively according to whether or not palisades of Vogt (POV were visible. En-face OCT images were then compared to in vivo confocal microscopy (IVCM in eleven eyes of 7 healthy and dry eye patients.En-face SD-OCT showed POV as a radially oriented network, located in superficial corneoscleral limbus, with a good correlation with IVCM features. It provided an easy and reproducible identification of POV without any special preparation or any direct contact, with a grading scale from 0 (no visualization to 3 (high visualization. The POV were found predominantly in superior (P<0.001 and inferior (P<0.001 quadrants when compared to the nasal and temporal quadrants for all subjects examined. The visibility score decreased with age (P<0.001 and was lower in dry eye patients (P<0.01. In addition, the score decreased in accordance with the severity of dry eye disease (P<0.001.En-face SD-OCT is a non-contact imaging technique that can be used to evaluate the POV, thus providing valuable information about differences in the limbal anatomy of dry eye patients as compared to healthy patients.

  14. Evaluation of a motion artifacts removal approach on breath-hold cine-magnetic resonance images of hypertrophic cardiomyopathy subjects

    Science.gov (United States)

    Betancur, Julián.; Simon, Antoine; Schnell, Frédéric; Donal, Erwan; Hernández, Alfredo; Garreau, Mireille

    2013-11-01

    The acquisition of ECG-gated cine magnetic resonance images of the heart is routinely performed in apnea in order to suppress the motion artifacts caused by breathing. However, many factors including the 2D nature of the acquisition and the use of di erent beats to acquire the multiple-view cine images, cause this kind of artifacts to appear. This paper presents the qualitative evaluation of a method aiming to remove motion artifacts in multipleview cine images acquired on patients with hypertrophic cardiomyopathy diagnosis. The approach uses iconic registration to reduce for in-plane artifacts in long-axis-view image stacks and in-plane and out-of-plane motion artifacts in sort-axis-view image stack. Four similarity measures were evaluated: the normalized correlation, the normalized mutual information, the sum of absolute voxel di erences and the Slomka metric proposed by Slomka et al. The qualitative evaluation assessed the misalignment of di erent anatomical structures of the left ventricle as follows: the misalignment of the interventricular septum and the lateral wall for short-axis-view acquisitions and the misalignment between the short-axis-view image and long-axis-view images. Results showed the correction using the normalized correlation as the most appropriated with an 80% of success.

  15. Magnetic resonance imaging of wrist and finger joints in healthy subjects occasionally shows changes resembling erosions and synovitis as seen in rheumatoid arthritis

    DEFF Research Database (Denmark)

    Ejbjerg, Bo; Narvestad, Eva; Rostrup, Egill

    2004-01-01

    OBJECTIVE: To explore the presence of changes resembling rheumatoid arthritis erosions and synovitis in metacarpophalangeal (MCP) and wrist joints of healthy individuals on magnetic resonance imaging (MRI) and to compare the MRI findings with conventional radiographic, clinical, and biochemical.......5%), while only minimal early synovial enhancement was detected by dynamic MRI. Three subjects had elevated serum levels of C-reactive protein, and these subjects displayed 44.5% of the synovitis-like changes and 41.7% of the erosion-like changes. Bone marrow edema-like changes were not found in any joints...

  16. 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.

  17. Quantitative Evaluation of Trabecular Bone Structure by Calcaneus MR Images Texture Analysis of Healthy Volunteers and Osteoporotic Subjects

    National Research Council Canada - National Science Library

    Herlidou, S

    2001-01-01

    The aim of this study is to evaluate, in vivo, trabecular bone structure of the calcaneus of healthy volunteers and osteoporotic patients by texture analysis of MR images Automated methods of texture...

  18. 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.

  19. A Study on the Psychological Evaluation of Tourism Landscape Images in HiroshimaA Psychological Evaluation by Korean Subjects

    National Research Council Canada - National Science Library

    Yoshihara, Toshiro; Nishina, Daisaku; Tanaka, Takahiro; Kawase, Kota; Takagishi, Hanako

    2017-01-01

    In this study, similarities and differences in psychological evaluations of sightseeing scenes in Hiroshima by Korean, Chinese and Japanese subjects were examined to identify new and attractive features for foreigners...

  20. Brain SPECT imaging and whole-body biodistribution with [{sup 123}I]ADAM - a serotonin transporter radiotracer in healthy human subjects

    Energy Technology Data Exchange (ETDEWEB)

    Lin, K.-J. [Graduate Institute of Clinical Medical Sciences, Chang-Gung University, Tao-Yuan 333, Taiwan (China); Molecular Imaging Center, Chang-Gung Memorial Hospital, Tao-Yuan 333, Taiwan (China); Department of Nuclear Medicine, Chang-Gung Memorial Hospital, Tao-Yuan 333, Taiwan (China); Liu, C.-Y. [Neuroscience Research Center, Chang-Gung Memorial Hospital, Tao-Yuan 333, Taiwan (China); Department of Psychiatry, Chang-Gung Memorial Hospital, Tao-Yuan 333, Taiwan (China); Wey, S.-P. [Molecular Imaging Center, Chang-Gung Memorial Hospital, Tao-Yuan 333, Taiwan (China); Department of Medical Imaging and Radiological Sciences, Chang-Gung University, Tao-Yuan 333, Taiwan (China); Hsiao, I.-T. [Molecular Imaging Center, Chang-Gung Memorial Hospital, Tao-Yuan 333, Taiwan (China); Department of Medical Imaging and Radiological Sciences, Chang-Gung University, Tao-Yuan 333, Taiwan (China); Wu, Jay [Health Physics Divisions, Atomic Energy Council, Institute of Nuclear Energy Research, Tao-Yuan 325, Taiwan (China); Fu, Y.-K. [Atomic Energy Council, Institute of Nuclear Energy Research, Tao-Yuan 325, Taiwan (China); Yen, T.-C. [Molecular Imaging Center, Chang-Gung Memorial Hospital, Tao-Yuan 333, Taiwan (China) and Department of Nuclear Medicine, Chang-Gung Memorial Hospital, Tao-Yuan 333, Taiwan (China)]. E-mail: yen1110@adm.cgmh.org.tw

    2006-02-15

    Introduction: [{sup 123}I]-2-((2-((dimethylamino)methyl)phenyl)thio)-5-iodophenylamine ([{sup 123}I]ADAM), a novel radiotracer, has promising application in the imaging of the serotonin transporter (SERT) in the human brain. In this study, the optimal scanning time for acquiring brain single photon emission computed tomography (SPECT) images was determined by performing dynamic SPECT studies at intervals from 0 to 6 h postinjection of [{sup 123}I]ADAM. Additionally, radiation-absorbed doses were determined for three healthy human subjects using attenuation-corrected images. Methods: Twelve subjects were randomized into one of three study groups as follows: whole-body distribution imaging (n=3), dynamic SPECT imaging (n=3) and brain SPECT imaging (n=6). The radiation-absorbed dose was calculated using MIRDOSE 3.0 software with attenuation-corrected data. The specific binding (SB) ratio of the brain stem was measured from dynamic SPECT images to determine the optimal scanning time. Results: Dynamic SPECT images showed that the SB of the brain stem gradually increased to a maximum 4 h postinjection. Single photon emission computed tomography images at 4 h postinjection showed a high uptake of the radiotracer (SB) in the hypothalamus (1.40{+-}0.12), brain stem (1.44{+-}0.16), pons (1.13{+-}0.14) and medial temporal lobe (0.59{+-}0.10). The mean adult male value of effective dose was 3.37x10{sup -2} mSv/MBq with a 4.8-h urine-voiding interval. Initial high uptake in SERT-rich sites was demonstrated in the lung and brain. A prominent washout of the radiotracer from the lung further increased brain radioactivity that reached a peak value of 5.03% of injected dose 40 min postinjection. Conclusions: [{sup 123}I]ADAM is a promising radiotracer for SPECT imaging of SERT in humans with acceptable dosimetry and high uptake in SERT-rich regions. Brain SPECT images taken within 4 h following injection show optimal levels of radiotracer uptake in known SERT sites. However, dynamic

  1. Temporal assessment of bone marrow lesions on magnetic resonance imaging in a canine model of knee osteoarthritis: impact of sequence selection.

    Science.gov (United States)

    d'Anjou, M-A; Troncy, E; Moreau, M; Abram, F; Raynauld, J-P; Martel-Pelletier, J; Pelletier, J-P

    2008-11-01

    To assess the evolution of bone marrow lesions (BMLs) in a canine model of knee osteoarthritis (OA) using three different magnetic resonance imaging (MRI) sequences. Three MRI sequences [coronal, T1-weighted three-dimensional fast gradient recalled echo (T1-GRE), sagittal fat-suppressed 3D spoiled gradient echo at a steady state (SPGR), and sagittal T2-weighted fast spin echo with fat saturation (T2-FS)] were performed at baseline, and at week 4, 8 and 26 in five dogs following transection of the anterior cruciate ligament. The same reader scored (0-3) subchondral BMLs twice, in blinded conditions, according to their extent in nine joint subregions, for all imaging sessions, and independently on the three MRI sequences. Correlation coefficients and Bland-Altman plots evaluated intra-reader repeatability. Readings scores were averaged and the nine subregions were summed to generate global BML scores. BMLs were most prevalent in the central and medial portions of the tibial plateau. Intra-reader repeatability was good to excellent for each sequence (r(s)=0.87-0.97; Pcanine OA model, the extent of BMLs varies in time on different MRI sequences. Until the complex nature of these lesions is fully resolved, it is suggested that to accurately assess the size and extent of BMLs, a combination of different sequences should be used.

  2. Revealing the sequence of interactions of PuroA peptide with Candida albicans cells by live-cell imaging

    Science.gov (United States)

    Shagaghi, Nadin; Bhave, Mrinal; Palombo, Enzo A.; Clayton, Andrew H. A.

    2017-03-01

    To determine the mechanism(s) of action of antimicrobial peptides (AMPs) it is desirable to provide details of their interaction kinetics with cellular, sub-cellular and molecular targets. The synthetic peptide, PuroA, displays potent antimicrobial activities which have been attributed to peptide-induced membrane destabilization, or intracellular mechanisms of action (DNA-binding) or both. We used time-lapse fluorescence microscopy and fluorescence lifetime imaging microscopy (FLIM) to directly monitor the localization and interaction kinetics of a FITC- PuroA peptide on single Candida albicans cells in real time. Our results reveal the sequence of events leading to cell death. Within 1 minute, FITC-PuroA was observed to interact with SYTO-labelled nucleic acids, resulting in a noticeable quenching in the fluorescence lifetime of the peptide label at the nucleus of yeast cells, and cell-cycle arrest. A propidium iodide (PI) influx assay confirmed that peptide translocation itself did not disrupt the cell membrane integrity; however, PI entry occurred 25-45 minutes later, which correlated with an increase in fractional fluorescence of pores and an overall loss of cell size. Our results clarify that membrane disruption appears to be the mechanism by which the C. albicans cells are killed and this occurs after FITC-PuroA translocation and binding to intracellular targets.

  3. Diagnostic performance of the three-dimensional fast spin echo-Cube sequence in comparison with a conventional imaging protocol in evaluation of the lachrymal drainage system

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jing; Chen, Lang; Wang, Qiu-Xia; Zhu, Wen-Zhen; Luo, Xin; Peng, Li [Huazhong University of Science and Technology, Department of Radiology, Tongji Hospital, Wuhan (China); Liu, Rong [Huazhong University of Science and Technology, Department of Ophthalmology, Tongji Hospital, Wuhan (China); Xiong, Wei [GE Healthcare China Wuhan Office, Wuhan (China)

    2014-10-15

    To compare the three-dimensional (3D)-fast spin-echo (FSE)-Cube with a conventional imaging protocol in evaluation of dacryostenosis. Thirty-three patients with epiphora underwent examinations using Cube magnetic resonance dacryocystography (MRD) and a conventional protocol, which included 3D fast-recovery fast spin-echo (FRFSE) MRD and two-dimensional (2D)-FSE sequences at 3.0 T. Using lachrymal endoscopic findings as the reference standard, we calculated the sensitivity and specificity of both protocols for detecting lachrymal drainage system (LDS) obstruction and their accuracies in depicting the level of obstruction. Comparable coronal and axial images were selected for bot sequences. Two neuroradiologists graded paired images for blurring, artefacts, anatomic details, and overall image quality. The two methods showed no significant difference in sensitivity (89.5 % vs. 94.7 %; p =0.674), specificity (64.3 %; p =1) or accuracy (86.8 %; p =1) in detecting or depicting LDS obstruction. Blurring and artefacts were significantly better on 2D-FSE images (p <0.01 and p <0.05, respectively). Anatomic details were significantly better on Cube reformats (p <0.001). No significant difference existed in overall image quality (p >0.05). In comparison with the conventional protocol, Cube MRD demonstrates satisfactory image quality and similar diagnostic capability for cases of possible LDS disease. (orig.)

  4. Assessment of the evaluation of liver T1 mapping imaging applying virtual ECG gating on a modified look-locker inversion recovery (MOLLI) pulse sequence

    Science.gov (United States)

    Yu, Seung-Man; Goo, Eun-Hoe; Lee, Suk-Jun; Choe, Bo-Young

    2014-10-01

    A T1 mapping calculation error may occur in a physicochemical environment with large relaxivity. We evaluated through a simulated electrocardiogram (ECG) the administration of a contrast with high relaxivity and its effect on the heart rate by using a modified Look-Locker inversion recovery (MOLLI) pulse sequence. The agarose 2% phantom of high relaxivity environment was developed by diluting gadoxetic acid magnetic resonance imaging (MRI) T1 contrast media. The gold standard T1 determination was based on coronal single section imaging with a 2D inversion-recovery turbo spin echo sequence (2D-IRTSE) in a 3T MR unit. Using the identical 3T MR scanner, we acquired T1 mapping for the MOLLI pulse sequence with various virtual heart rates. T1 mapping data of the two different pulse sequences ( i.e., 2D-IRTSE and MOLLI) were measured to investigate the accuracy and the specificity. An in vivo study was conducted in the same manner as the phantom experiments for liver T1 mapping imaging in three healthy volunteers. The MOLLI pulse sequence showed an error rate of less than 10% at a contrast agent concentration of 0.4 mmol/L, and significant error, compared with the reference value, was observed at 0.6 mmol/L or higher. The percentage error of the T1 value did not correlated with the RR ( i.e., the time between heart beats) change that was observed (P =.270). Based on the in-vivo liver test, T1 mapping imaging of an abdominal organ as the liver can be successfully achieved using the applied virtual ECG gating on the MOLLI sequence.

  5. 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.

  6. 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

  7. Diffusion-prepared stimulated-echo turbo spin echo (DPsti-TSE): An eddy current-insensitive sequence for three-dimensional high-resolution and undistorted diffusion-weighted imaging.

    Science.gov (United States)

    Zhang, Qinwei; Coolen, Bram F; Versluis, Maarten J; Strijkers, Gustav J; Nederveen, Aart J

    2017-07-01

    In this study, we present a new three-dimensional (3D), diffusion-prepared turbo spin echo sequence based on a stimulated-echo read-out (DPsti-TSE) enabling high-resolution and undistorted diffusion-weighted imaging (DWI). A dephasing gradient in the diffusion preparation module and rephasing gradients in the turbo spin echo module create stimulated echoes, which prevent signal loss caused by eddy currents. Near to perfect agreement of apparent diffusion coefficient (ADC) values between DPsti-TSE and diffusion-weighted echo planar imaging (DW-EPI) was demonstrated in both phantom transient signal experiments and phantom imaging experiments. High-resolution and undistorted DPsti-TSE was demonstrated in vivo in prostate and carotid vessel wall. 3D whole-prostate DWI was achieved with four b values in only 6 min. Undistorted ADC maps of the prostate peripheral zone were obtained at low and high imaging resolutions with no change in mean ADC values [(1.60 ± 0.10) × 10-3 versus (1.60 ± 0.02) × 10-3  mm2 /s]. High-resolution 3D DWI of the carotid vessel wall was achieved in 12 min, with consistent ADC values [(1.40 ± 0.23) × 10-3  mm2 /s] across different subjects, as well as slice locations through the imaging volume. This study shows that DPsti-TSE can serve as a robust 3D diffusion-weighted sequence and is an attractive alternative to the traditional two-dimensional DW-EPI approaches. Copyright © 2017 John Wiley & Sons, Ltd.

  8. Disparity in neural and subjective responses to food images in women with obesity and normal-weight women.

    Science.gov (United States)

    Carbine, Kaylie A; Larson, Michael J; Romney, Lora; Bailey, Bruce W; Tucker, Larry A; Christensen, William F; LeCheminant, James D

    2017-02-01

    Self-reports tend to differ from objective measurements of food intake, particularly in adults with obesity; however, no studies have examined how neural responses to food (an objective measure) and subjective ratings of food differ by BMI status. This study tested normal-weight women (NWW) and women with obesity (OBW) for group differences in neural indices of attention towards food pictures, subjective ratings of these pictures, and the disparity between objective and subjective measurements. Twenty-two NWW (21.8 ± 1.7 kg/m 2 ) and 22 OBW (37.0 ± 5.7 kg/m 2 ) viewed food and flower pictures while late positive potential amplitude, an event-related potential, was recorded. Participants rated pictures for arousal and valence. Late positive potential amplitude was larger toward food than flower pictures. OBW self-reported flower pictures as more pleasant than food; NWW showed no difference for pleasantness. There were no significant main effects or interactions for arousal. Standardized scores showed that only on subjective, but not objective, measures did OBW compared with NWW disproportionately indicate food pictures as less pleasant than flowers. Compared with NWW, OBW showed larger discrepancies between neural and subjective reports of attention towards food. Inaccurate self-reports of attention towards food may reduce the efficiency of health interventions. © 2016 The Obesity Society.

  9. Objective and subjective image quality of primary and recurrent squamous cell carcinoma on head and neck low-tube-voltage 80-kVp computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Scholtz, Jan-Erik; Kaup, Moritz; Kraft, Johannes; Noeske, Eva-Maria; Schulz, Boris; Burck, Iris; Kerl, J.M.; Bauer, Ralf W.; Lehnert, Thomas; Vogl, Thomas J.; Wichmann, Julian L. [University Hospital Frankfurt, Department of Diagnostic and Interventional Radiology, Frankfurt (Germany); Scheerer, Friedrich [University Hospital Frankfurt, Department of Cranio-Maxillofacial and Plastic Facial Surgery, Frankfurt (Germany); Wagenblast, Jens [University Hospital Frankfurt, Department of Otolaryngology, Head and Neck Surgery, Frankfurt (Germany)

    2015-03-26

    To investigate low-tube-voltage 80-kVp computed tomography (CT) of head and neck primary and recurrent squamous cell carcinoma (SCC) regarding objective and subjective image quality. We retrospectively evaluated 65 patients (47 male, 18 female; mean age: 62.1 years) who underwent head and neck dual-energy CT (DECT) due to biopsy-proven primary (n = 50) or recurrent (n = 15) SCC. Eighty peak kilovoltage and standard blended 120-kVp images were compared. Attenuation and noise of malignancy and various soft tissue structures were measured. Tumor signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. Subjective image quality was rated by three reviewers using 5-point grading scales regarding overall image quality, lesion delineation, image sharpness, and image noise. Radiation dose was assessed as CT dose index volume (CTDI{sub vol}). Interobserver agreement was calculated using intraclass correlation coefficient (ICC). Mean tumor attenuation (153.8 Hounsfield unit (HU) vs. 97.1 HU), SNR (10.7 vs. 8.3), CNR (8.1 vs. 4.8), and subjective tumor delineation (score, 4.46 vs. 4.13) were significantly increased (all P < 0.001) with 80-kVp acquisition compared to standard blended 120-kVp images. Noise of all measured structures was increased in 80-kVp acquisition (P < 0.001). Overall interobserver agreement was good (ICC, 0.86; 95 % confidence intervals: 0.82-0.89). CTDI{sub vol} was reduced by 48.7 % with 80-kVp acquisition compared to standard DECT (4.85 ± 0.51 vs. 9.94 ± 0.81 mGy cm, P < 0.001). Head and neck CT with low-tube-voltage 80-kVp acquisition provides increased tumor delineation, SNR, and CNR for CT imaging of primary and recurrent SCC compared to standard 120-kVp acquisition with an accompanying significant reduction of radiation exposure. (orig.)

  10. Statistical Evaluations of the Reproducibility and Reliability of 3-Tesla High Resolution Magnetization Transfer Brain Images: A Pilot Study on Healthy Subjects

    Directory of Open Access Journals (Sweden)

    Kelly H. Zou

    2010-01-01

    Full Text Available Magnetization transfer imaging (MT may have considerable promise for early detection and monitoring of subtle brain changes before they are apparent on conventional magnetic resonance images. At 3 Tesla (T, MT affords higher resolution and increased tissue contrast associated with macromolecules. The reliability and reproducibility of a new high-resolution MT strategy were assessed in brain images acquired from 9 healthy subjects. Repeated measures were taken for 12 brain regions of interest (ROIs: genu, splenium, and the left and right hemispheres of the hippocampus, caudate, putamen, thalamus, and cerebral white matter. Spearman's correlation coefficient, coefficient of variation, and intraclass correlation coefficient (ICC were computed. Multivariate mixed-effects regression models were used to fit the mean ROI values and to test the significance of the effects due to region, subject, observer, time, and manual repetition. A sensitivity analysis of various model specifications and the corresponding ICCs was conducted. Our statistical methods may be generalized to many similar evaluative studies of the reliability and reproducibility of various imaging modalities.

  11. Diastolic Dysfunction of Hypertrophic Cardiomyopathy Genotype-Positive Subjects Without Hypertrophy Is Detected by Tissue Doppler Imaging: A Systematic Review and Meta-analysis.

    Science.gov (United States)

    Liu, Wen; Sun, Dandan; Yang, Jun

    2017-10-01

    To evaluate whether diastolic dysfunction derived by tissue Doppler imaging (TDI) would be an earlier manifestation in genotype-positive hypertrophic cardiomyopathy (HCM) subjects without left ventricular hypertrophy (LVH). We systematically searched Pubmed, Medline, and Web of Science with an upper date limit of June 2016 for studies evaluating the diastolic function of HCM genotype-positive subjects without hypertrophy (G+/LVH-). Based on the inclusion criteria, eligible studies were selected. The quality of selected studies was assessed by the Newcastle-Ottawa Scale before being included in the meta-analysis. The statistic data such as weighted mean difference (WMD) and 95% confidence interval (CI) were calculated by Stata 12.0 software. Seventeen studies were included in the systematic review, and 12 were finally involved in the meta-analysis. The G+/LVH- subjects showed decreased Ea derived by TDI on both the interventricular septum (WMD [95% CI] = -1.822 [-3.104, -0.541]) and lateral wall (WMD [95% CI] = -2.269 [-3.820, -0.719]), and increased E/Ea on both interventricular septum (WMD [95% CI] = 1.363 [0.552, 2.174]) and lateral (WMD [95% CI] = 1.339 [0.386, 2.293]) wall. Tissue Doppler imaging-derived diastolic dysfunction can be found in HCM genotype-positive subjects without hypertrophy. © 2017 by the American Institute of Ultrasound in Medicine.

  12. Automated short-axis cardiac magnetic resonance image acquisitions: accuracy of left ventricular dimension measurements in normal subjects and patients.

    Science.gov (United States)

    Danilouchkine, Mikhail G; Westenberg, Jos J M; Reiber, Johan H C; Lelieveldt, Boudewijn P F

    2004-12-01

    This study investigates the use of an automated observer-independent planning system for short-axis cardiovascular magnetic resonance (MR) acquisitions in the clinical environment. The capacity of the automated method to produce accurate measurements of left ventricular dimensions and function was quantitatively assessed in normal subjects and patients. Fourteen healthy volunteers and 8 patients underwent cardiovascular MR (CMR) acquisitions for ventricular function assessment. Short-axis datasets of the left ventricle (LV) were acquired in 2 ways: manually planned and generated in an automatic fashion. End-diastolic volume (EDV), end-systolic volume (ESV), ejection fraction (EF), and left ventricular mass (LVM) were derived from the 2 datasets. The agreement between the manual and automatic planning methods was assessed. The mean differences between the manual and automated CMR planning methods for the normal subjects and patients were 5.89 mL and 1.93 mL (EDV), 1.14 mL and -0.41 mL (ESV), 0.81% and 0.89% (EF), and 4.35 g and 3.88 g (LVM), respectively. There was no significant difference in ESV and EF. LVM significantly differed in both groups, whereas EDV was significantly different in the normal subjects and insignificantly different in the patients. The variability coefficients were 2.8 and 3.59 (EDV), 3.3 and 5.03 (ESV), 1.79 and 2.65 (EF), and 4.36 and 2.27 (LVM) for the normal subjects and patients, respectively. The mean angular deviation of the LV axes turned out to be 8.58 +/- 5.76 degrees for the normal subjects and 8.35 +/- 5.15 degrees for the patients. Automated CMR planning method can provide accurate measurements of LV dimensions in normal subjects and patients, and therefore, can be used in the clinical environment for functional assessment of the human cardiovascular system.

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

    Science.gov (United States)

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

    2015-01-01

    T2-weighted (T2w) sequences are commonly relied upon in magnetic resonance imaging protocols for the detection of brain lesions in dogs. Previously, the effect of fluid suppression via fluid-attenuated inversion recovery (FLAIR) has been compared to T2-weighting with mixed results. Short tau inversion recovery (STIR) has been reported to increase the detection of some CNS lesions in people. The purpose of the current study was to evaluate the effect of fat suppression on brain parenchymal contrast resolution and lesion detection in dogs. We compared three sequences: T2w images, STIR, and T2w FLAIR with chemical fat suppression (T2-FLAIR-FS) in dogs with meningoencephalitis. Dogs with meningoencephalitis and dogs with idiopathic epilepsy were retrospectively identified and anonymized. Evaluators recorded the presence or absence of lesions within 12 predetermined brain regions on randomized sequences, viewing and scoring each sequence individually. Additionally, signal-to-noise ratios, contrast-to-noise ratios, and relative contrast (RC) were measured in a reference population. Short tau inversion recovery sequences had the highest RC between gray and white matter. While descriptively more lesions were identified by evaluators on T2-FLAIR-FS images, there was no statistical difference in the relative sensitivity of lesion detection between the sequences. Nor was there a statistical difference in false lesion detection within our reference population. Short tau inversion recovery may be favored for enhanced anatomic contrast depiction in brain imaging. No benefit of the inclusion of a fat-suppressed T2-FLAIR sequence was found. © 2014 American College of Veterinary Radiology.

  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. DIRBoost-An algorithm for boosting deformable image registration: Application to lung CT intra-subject registration

    NARCIS (Netherlands)

    Muenzing, S.E.; Ginneken, B. van; Viergever, M.A.; Pluim, J.P.

    2014-01-01

    We introduce a boosting algorithm to improve on existing methods for deformable image registration (DIR). The proposed DIRBoost algorithm is inspired by the theory on hypothesis boosting, well known in the field of machine learning. DIRBoost utilizes a method for automatic registration error

  16. Positive contrast MR imaging of tendons, ligaments, and menisci by subtraction of signals from a double echo steady state sequence (Sub-DESS).

    Science.gov (United States)

    Martirosian, Petros; Schraml, Christina; Springer, Fabian; Schwenzer, Nina F; Würslin, Christian; Schick, Fritz; Deimling, Michael

    2014-01-01

    To improve the visualization of fibrous tissues as tendons, ligaments and fibrocartilage structures as menisci by positive contrast using a new 3D Double Echo Steady State (DESS) sequence. The proposed 3D DESS sequence works with separate acquisition of a first echo with an echo time (TE1 ) of 1.2 ms followed by a more heavily T2 -weighted second echo recorded at time TE2 . Subtraction of images from both echoes leads to positive signal from fibrous tissues, whereas in other tissues as musculature and fat the subtraction signal nearly vanishes due to almost similar signal strength in both echoes. Systematic measurements in healthy volunteers with different sets of pulse repetition time (TR), TE1 , readout bandwidth and flip angle were performed to determine optimal sequence parameters. The presented 3D sequence with Cartesian readout requires relatively short measuring time, provides reasonable signal-to-noise ratio and can be easily implemented in protocols for clinical musculoskeletal MR imaging. Degenerative changes or tears of tendons, ligaments and fibrocartilage are known to cause increased water content and therefore prolongation of transverse relaxation times, which leads to reduced signal intensities in the "subtraction images." Positive contrast of fibrous tissue as demonstrated by the proposed sub-DESS approach provides improved conspicuity and allows for three-dimensional reconstruction especially of structures with curved geometry. Copyright © 2013 Wiley Periodicals, Inc.

  17. Characterization of regional left ventricular function in nonhuman primates using magnetic resonance imaging biomarkers: a test-retest repeatability and inter-subject variability study.

    Directory of Open Access Journals (Sweden)

    Smita Sampath

    Full Text Available Pre-clinical animal models are important to study the fundamental biological and functional mechanisms involved in the longitudinal evolution of heart failure (HF. Particularly, large animal models, like nonhuman primates (NHPs, that possess greater physiological, biochemical, and phylogenetic similarity to humans are gaining interest. To assess the translatability of these models into human diseases, imaging biomarkers play a significant role in non-invasive phenotyping, prediction of downstream remodeling, and evaluation of novel experimental therapeutics. This paper sheds insight into NHP cardiac function through the quantification of magnetic resonance (MR imaging biomarkers that comprehensively characterize the spatiotemporal dynamics of left ventricular (LV systolic pumping and LV diastolic relaxation. MR tagging and phase contrast (PC imaging were used to quantify NHP cardiac strain and flow. Temporal inter-relationships between rotational mechanics, myocardial strain and LV chamber flow are presented, and functional biomarkers are evaluated through test-retest repeatability and inter subject variability analyses. The temporal trends observed in strain and flow was similar to published data in humans. Our results indicate a dominant dimension based pumping during early systole, followed by a torsion dominant pumping action during late systole. Early diastole is characterized by close to 65% of untwist, the remainder of which likely contributes to efficient filling during atrial kick. Our data reveal that moderate to good intra-subject repeatability was observed for peak strain, strain-rates, E/circumferential strain-rate (CSR ratio, E/longitudinal strain-rate (LSR ratio, and deceleration time. The inter-subject variability was high for strain dyssynchrony, diastolic strain-rates, peak torsion and peak untwist rate. We have successfully characterized cardiac function in NHPs using MR imaging. Peak strain, average systolic strain

  18. Liver imaging at 3.0 T: Diffusion-induced black-blood echo-planar imaging with large anatomic volumetric coverage as an alternative for specific absorption rate-intensive echo-train spin-echo sequences: Feasibility study

    NARCIS (Netherlands)

    I.C. van den Bos (Indra); S.M. Hussain (Shahid); G.P. Krestin (Gabriel); P.A. Wielopolski (Piotr)

    2008-01-01

    textabstractInstitutional Review Board approval and signed informed consent were obtained by all participants for an ongoing sequence optimization project at 3.0 T. The purpose of this study was to evaluate breath-hold diffusion-induced blackblood echo-planar imaging (BBEPI) as a potential

  19. Comparison of observer reliability of three-dimensional cephalometric landmark identification on subject images from Galileos and i-CAT cone beam CT.

    Science.gov (United States)

    Katkar, R A; Kummet, C; Dawson, D; Moreno Uribe, L; Allareddy, V; Finkelstein, M; Ruprecht, A

    2013-01-01

    Recently, there has been increasing interest in the use of cone beam CT (CBCT) for three-dimensional cephalometric analysis and craniofacial reconstruction in orthodontic and orthognathic surgical treatment planning. However, there is a need to redefine the cephalometric landmarks in three dimensional cephalometric analysis and to demonstrate the reproducibility of landmark identification on the type of CBCT machine being used. CBCT images of 20 subjects aged 15-25 years were selected, ten each from Galileos(®) (Sirona Dental Systems Inc., Bensheim, Germany) and Next Generation i-CAT(®) (Imaging Sciences International, Hatfield, PA). 2 observers located 18 landmarks on each subject twice using Dolphin-3D v. 11 software (Dolphin Imaging and Management Systems, Chatsworth, CA). Inter- and intraobserver reliability was assessed using Euclidean distances and linear mixed models. Overall, the intra- and interobserver reliability was excellent for both machines. The landmarks Gonion, Nasion, Orbitale and Anterior Nasal Spine (ANS) showed the greatest median Euclidean distances for both intra- and interobserver measurements. There were significant observer effects in the unified models for Sella, Menton and all six dental landmarks. For Sella, the distances between the measures were significantly smaller (more closely spaced) on the i-CAT machine than on the Galileos in both intra- and interobserver measurements. The intra- and interobserver reliability was excellent for both machines. Some of the landmarks were not as reproducible as others. Which machine produced the highest reliability depended on the landmark considered.

  20. Comparison of 3D double inversion recovery and 2D STIR FLAIR MR sequences for the imaging of optic neuritis: pilot study

    Energy Technology Data Exchange (ETDEWEB)

    Hodel, Jerome; Bocher, Anne-Laure; Pruvo, Jean-Pierre; Leclerc, Xavier [Hopital Roger Salengro, Department of Neuroradiology, Lille (France); Outteryck, Olivier; Zephir, Helene; Vermersch, Patrick [Hopital Roger Salengro, Department of Neurology, Lille (France); Lambert, Oriane [Fondation Ophtalmologique Rothschild, Department of Neuroradiology, Paris (France); Benadjaoud, Mohamed Amine [Radiation Epidemiology Team, Inserm, CESP Centre for Research in Epidemiology and Population Health, U1018, Villejuif (France); Chechin, David [Philips Medical Systems, Suresnes (France)

    2014-12-15

    We compared the three-dimensional (3D) double inversion recovery (DIR) magnetic resonance imaging (MRI) sequence with the coronal two-dimensional (2D) short tau inversion recovery (STIR) fluid-attenuated inversion recovery (FLAIR) for the detection of optic nerve signal abnormality in patients with optic neuritis (ON). The study group consisted of 31 patients with ON (44 pathological nerves) confirmed by visual-evoked potentials used as the reference. MRI examinations included 2D coronal STIR FLAIR and 3D DIR with 3-mm coronal reformats to match with STIR FLAIR. Image artefacts were graded for each portion of the optic nerves. Each set of MR images (2D STIR FLAIR, DIR reformats and multiplanar 3D DIR) was examined independently and separately for the detection of signal abnormality. Cisternal portion of optic nerves was better delineated with DIR (p < 0.001), while artefacts impaired analysis in four patients with STIR FLAIR. Inter-observer agreement was significantly improved (p < 0.001) on 3D DIR (κ = 0.96) compared with STIR FLAIR images (κ = 0.60). Multiplanar DIR images reached the best performance for the diagnosis of ON (95 % sensitive and 94 % specific). Our study showed a high sensitivity and specificity of 3D DIR compared with STIR FLAIR for the detection of ON. These findings suggest that the 3D DIR sequence may be more useful in patients suspected of ON. (orig.)

  1. The use of ultrasound imaging of the abdominal drawing-in maneuver in subjects with low back pain.

    Science.gov (United States)

    Teyhen, Deydre S; Miltenberger, Chad E; Deiters, Henry M; Del Toro, Yadira M; Pulliam, Jennifer N; Childs, John D; Boyles, Robert E; Flynn, Timothy W

    2005-06-01

    Randomized controlled trial among patients with low back pain (LBP). (1) Determine the reliability of real-time ultrasound imaging for assessing activation of the lateral abdominal muscles; (2) characterize the extent to which the abdominal drawing-in maneuver (ADIM) results in preferential activation of the transverse abdominis (TrA); and (3) determine if ultrasound biofeedback improves short-term performance of the ADIM in patients with LBP. Ultrasound imaging is reportedly useful for measuring and training patients to preferentially activate the TrA muscle. However, research to support these claims is limited. Thirty patients with LBP referred for lumbar stabilization training were randomized to receive either traditional training (n = 15) or traditional training with biofeedback (n = 15). Ultrasound imaging was used to measure changes in thickness of the lateral abdominal muscles. Differences in preferential changes in muscle thickness of the TrA between groups and across time were assessed using analysis of variance. Intrarater reliability measuring lateral abdominal muscle thickness exceeded 0.93. On average, patients in both groups demonstrated a 2-fold increase in the thickness of the TrA during the ADIM. Performance of the ADIM did not differ between the groups. These data provide construct validity for the notion that the ADIM results in preferential activation of the TrA in patients with LBP. Although, the addition of biofeedback did not enhance the ability to perform the ADIM at a short-term follow-up, our data suggest a possible ceiling effect or an insufficient training stimulus. Further research is necessary to determine if there is a subgroup of patients with LBP who may benefit from biofeedback.

  2. Inversion in the steady state: contrast optimization and reduced imaging time with fast three-dimensional inversion-recovery-prepared GRE pulse sequences.

    Science.gov (United States)

    Foo, T K; Sawyer, A M; Faulkner, W H; Mills, D G

    1994-04-01

    To evaluate the differences in contrast between 1-second delay and zero delay (for magnetization recovery) before the preparation radio-frequency pulse in three-dimensional, inversion-recovery (IR) fast gradient-echo (GRE) acquisitions. Mathematical simulations and measurements of brain image contrast were performed with healthy volunteers and 10 patients. The zero-delay sequence generated T1-weighted contrast similar to that obtained with 1-second delay but was accompanied by a substantial reduction in imaging time. However, the zero delay prohibits full recovery of the longitudinal magnetization. Hence, the signal null characteristic of IR experiments is not easily observed, since it occurs (as a function of tissue T1) at very short inversion times (prepared rapid GRE sequences with a 1-second delay and preparation time (TP) of 600-700 msec can be achieved in less time by using a zero delay and a shorter TP (400-500 msec).

  3. Feasibility of strain and strain rate imaging for the assessment of regional left atrial deformation: a study in normal subjects.

    Science.gov (United States)

    Sirbu, C; Herbots, L; D'hooge, J; Claus, P; Marciniak, A; Langeland, T; Bijnens, B; Rademakers, F E; Sutherland, G R

    2006-06-01

    There are no data on the use of Myocardial Velocity Imaging (MVI) to study the left atrium (LA) wall deformation. The aims of this study were to assess the feasibility of measuring regional longitudinal strain/strain rate (epsilon/SR) profiles in the LA wall, to define the normal values and to validate these measurements. MVI data were recorded in 40 healthy young individuals using a GE Vivid7 for the lateral, anterior and inferior LA walls. The peak epsilon/SR values and total epsilon values during the contractile, reservoir and conduit LA phases were measured. For the LA lateral wall, the total epsilon values were correlated with the LA volumetric indicators (LA active emptying fraction: LA AEF; LA expansion index: LA EI; and LA passive emptying fraction: LA PEF). The correlations were significant for all three periods: contractile (total epsilon vs. LA AEF, r=-0.78, P<0.001), reservoir (total epsilon vs. LA EI, r=0.43, P<0.01) and conduit (total epsilon vs. LA PEF, r=-0.46, P<0.005). SR/epsilon imaging for the quantification of longitudinal myocardial LA deformation was shown to be feasible and the normal values were reported and validated. These data may improve the understanding of the LA pathophysiology.

  4. Evaluation of three-dimensional navigator-gated whole heart MR coronary angiography: The importance of systolic imaging in subjects with high heart rates

    Energy Technology Data Exchange (ETDEWEB)

    Wu Yenwen [Department of Diagnostic Imaging, Kyoto University Graduate School of Medicine, 54 Shogoinkawahara-cho, Sakyo-ku, Kyoto 606-8507 (Japan); Tadamura, Eiji [Department of Diagnostic Imaging, Kyoto University Graduate School of Medicine, 54 Shogoinkawahara-cho, Sakyo-ku, Kyoto 606-8507 (Japan)]. E-mail: et@kuhp.kyoto-u.ac.jp; Yamamuro, Masaki [Department of Diagnostic Imaging, Kyoto University Graduate School of Medicine, 54 Shogoinkawahara-cho, Sakyo-ku, Kyoto 606-8507 (Japan); Kanao, Shotaro [Department of Diagnostic Imaging, Kyoto University Graduate School of Medicine, 54 Shogoinkawahara-cho, Sakyo-ku, Kyoto 606-8507 (Japan); Nakayama, Kazuki [Department of Radiology, Sakazaki Clinic, 11 Nishinokyoshimoai-cho, Nakagyo-ku, Kyoto 604-8436 (Japan); Togashi, Kaori [Department of Diagnostic Imaging, Kyoto University Graduate School of Medicine, 54 Shogoinkawahara-cho, Sakyo-ku, Kyoto 606-8507 (Japan)

    2007-01-15

    Purpose: To evaluate the influence of heart rate (HR) on magnetic resonance coronary angiography (MRCA) image quality in diastolic and systolic phases. Materials and methods: Twenty-seven healthy volunteers (9 men; 33 {+-} 9 years, HR 53-110 bpm), were evaluated with the electrocardiography and three-dimensional navigator-gating MRCA in a 1.5-T MR scanner (Avanto, Siemens) in diastolic and systolic phases (steady-state free precession; TR/TE/flip angle = 3.2 ms/1.6 ms/90{sup o}). The timing of scanning was individually adapted to the cardiac rest periods obtained in the prescanning, by visually identifying when the movement of right coronary artery was minimized during diastole and systole. Images of two phases were side-by-side compared on a four-point scale (from 1 = poor to 4 = excellent visibility; score of 3 or 4 as diagnostic). Results: Of 13 subjects with HR {<=}65 bpm (low HR group, mean 59.8 {+-} 4.9 bpm, range 53-65), the image quality scores were significantly better than that with higher heart rates (73.9 {+-} 9.0 bpm, range 68-110) in diastolic MRCA. The image quality was significantly improved during systole in high HR group. Overall, 91.3% of low HR group had MRCA image of diagnostic quality acquired at diastole, while 88.3% of high HR group had diagnostic images at systole by segmental analysis (p = NS). Conclusions: MRCA at systole offered superior quality in patients with high heart rates.

  5. Encoding and recall of finger sequences in experienced pianists compared with musically naïve controls: a combined behavioral and functional imaging study.

    Science.gov (United States)

    Pau, S; Jahn, G; Sakreida, K; Domin, M; Lotze, M

    2013-01-01

    Long-term intensive sensorimotor training alters functional representation of the motor and sensory system and might even result in structural changes. However, there is not much knowledge about how previous training impacts learning transfer and functional representation. We tested 14 amateur pianists and 15 musically naïve participants in a short-term finger sequence training procedure, differing considerably from piano playing and measured associated functional representation with functional magnetic resonance imaging. The conditions consisted of encoding a finger sequence indicated by hand symbols ("sequence encoding") and subsequently replaying the sequence from memory, both with and without auditory feedback ("sequence retrieval"). Piano players activated motor areas and the mirror neuron system more strongly than musically naïve participants during encoding. When retrieving the sequence, musically naïve participants showed higher activation in similar brain areas. Thus, retrieval activations of naïve participants were comparable to encoding activations of piano players, who during retrieval performed the sequences more accurately despite lower motor activations. Interestingly, both groups showed primary auditory activation even during sequence retrieval without auditory feedback, supporting previous reports about coactivation of the auditory cortex after learned association with motor performance. When playing with auditory feedback, only pianists lateralized to the left auditory cortex. During encoding activation in left primary somatosensory cortex in the height of the finger representations had a predictive value for increased motor performance later on (error rates). Contrarily, decreased performance was associated with increased visual cortex activation during encoding. Our study extends previous reports about training transfer of motor knowledge resulting in superior training effects in musicians. Performance increase went along with activity in

  6. Impact of head models in N170 component source imaging: results in control subjects and ADHD patients

    Science.gov (United States)

    Beltrachini, L.; Blenkmann, A.; von Ellenrieder, N.; Petroni, A.; Urquina, H.; Manes, F.; Ibáñez, A.; Muravchik, C. H.

    2011-12-01

    The major goal of evoked related potential studies arise in source localization techniques to identify the loci of neural activity that give rise to a particular voltage distribution measured on the surface of the scalp. In this paper we evaluate the effect of the head model adopted in order to estimate the N170 component source in attention deficit hyperactivity disorder (ADHD) patients and control subjects, considering faces and words stimuli. The standardized low resolution brain electromagnetic tomography algorithm (sLORETA) is used to compare between the three shell spherical head model and a fully realistic model based on the ICBM-152 atlas. We compare their variance on source estimation and analyze the impact on the N170 source localization. Results show that the often used three shell spherical model may lead to erroneous solutions, specially on ADHD patients, so its use is not recommended. Our results also suggest that N170 sources are mainly located in the right occipital fusiform gyrus for faces stimuli and in the left occipital fusiform gyrus for words stimuli, for both control subjects and ADHD patients. We also found a notable decrease on the N170 estimated source amplitude on ADHD patients, resulting in a plausible marker of the disease.

  7. Factors affecting subjective appearance evaluations among patients with congenital craniofacial conditions: An application of Cash's cognitive-behavioural model of body image development.

    Science.gov (United States)

    Feragen, Kristin Billaud; Stock, Nicola Marie

    2018-01-30

    Satisfaction with appearance is of central importance for psychological well-being and health. For individuals with an unusual appearance, such as congenital craniofacial anomalies (CFA), appearance evaluations could be especially important. However, few, if any papers have presented a comprehensive synthesis of the factors found to affect subjective satisfaction with appearance among children, adolescents, and adults born with a CFA. Further, only a handful of craniofacial studies have applied psychological theories or models to their findings, resulting in an overall lack of guidance for researchers in the field. This paper summarises the literature pertaining to satisfaction with appearance among those affected by CFAs, and examines the extent to which Cash's cognitive-behavioural model of body image development (2012) fits with this literature. Given the overlap between factors of interest in the field of CFAs, and in the area of body image more broadly, a closer collaboration between the two research fields is suggested. Copyright © 2018 Elsevier Ltd. All rights reserved.

  8. 1D and 2D diffusion pore imaging on a preclinical MR system using adaptive rephasing: Feasibility and pulse sequence comparison.

    Science.gov (United States)

    Bertleff, Marco; Domsch, Sebastian; Laun, Frederik B; Kuder, Tristan A; Schad, Lothar R

    2017-05-01

    Diffusion pore imaging (DPI) has recently been proposed as a means to acquire images of the average pore shape in an image voxel or region of interest. The highly asymmetric gradient scheme of its sequence makes it substantially demanding in terms of the hardware of the NMR system. The aim of this work is to show the feasibility of DPI on a preclinical 9.4T animal scanner. Using water-filled capillaries with an inner radius of 10μm, four different variants of the DPI sequence were compared in 1D and 2D measurements. The pulse sequences applied cover the basic implementation using one long and one temporally narrow gradient pulse, a CPMG-like variant with multiple refocusing RF pulses as well as two variants splitting up the long gradient and distributing it on either side of the refocusing pulse. Substantial differences between the methods were found in terms of signal-to-noise ratio, contrast, blurring, deviations from the expected results and sensitivity to gradient imperfections. Each of the tested sequences was found to produce characteristic gradient mismatches dependent on the absolute value, direction and sign of the applied q-value. Read gradients were applied to compensate these mismatches translating them into time shifts, which enabled 1D DPI yielding capillary radius estimations within the tolerances specified by the manufacturer. For a successful DPI application in 2D, a novel gradient amplitude adaption scheme was implemented to correct for the occurring time shifts. Using this adaption, higher conformity to the expected pore shape, reduced blurring and enhanced contrast were achieved. Images of the phantom's pore shape could be acquired with a nominal resolution of 2.2μm. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. Thoracic staging of non-small-cell lung cancer using integrated {sup 18}F-FDG PET/MR imaging: diagnostic value of different MR sequences

    Energy Technology Data Exchange (ETDEWEB)

    Schaarschmidt, Benedikt [University of Dusseldorf, Department of Diagnostic and Interventional Radiology, Medical Faculty, Duesseldorf (Germany); University of Duisburg-Essen, Department of Diagnostic and Interventional Radiology and Neuroradiology, Medical Faculty, Essen (Germany); Buchbender, Christian; Rubbert, Christian; Hild, Florian; Antoch, Gerald; Heusch, Philipp [University of Dusseldorf, Department of Diagnostic and Interventional Radiology, Medical Faculty, Duesseldorf (Germany); Gomez, Benedikt; Ruhlmann, Verena [University of Duisburg-Essen, Department of Nuclear Medicine, Medical Faculty, Essen (Germany); Koehler, Jens [University of Duisburg-Essen, Department of Medical Oncology, Medical Faculty, Essen (Germany); Grueneisen, Johannes; Wetter, Axel [University of Duisburg-Essen, Department of Diagnostic and Interventional Radiology and Neuroradiology, Medical Faculty, Essen (Germany); Reis, Henning [University of Duisburg-Essen, Institute of Pathology, Medical Faculty, Essen (Germany); Quick, Harald H. [University of Duisburg-Essen, Erwin L. Hahn Institute for MR Imaging, Essen (Germany); University Hospital Essen, High Field and Hybrid MR Imaging, Essen (Germany)

    2015-07-15

    To compare the accuracy of different MR sequences in simultaneous PET/MR imaging for T staging in non-small-cell lung cancer in relation to histopathology. The study included 28 patients who underwent dedicated thoracic PET/MR imaging before tumour resection. Local tumour staging was performed separately by three readers with each of the following MR sequences together with PET: transverse T2 BLADE, transverse non-enhanced and contrast-enhanced T1 FLASH, T1 3D Dixon VIBE in transverse and coronal orientation, coronal T2 HASTE, and coronal TrueFISP. The staging results were compared with histopathology after resection as the reference standard. Differences in the accuracy of T staging among the MR sequences were evaluated using McNemar's test. Due to multiple testing, Bonferroni correction was applied to prevent accumulation of α errors; p < 0.0024 was considered statistically significant. Compared with histopathology, T-staging accuracy was 69 % with T2 BLADE, 68 % with T2 HASTE, 59 % with contrast-enhanced T1 FLASH, 57 % with TrueFISP, 50 % with non-enhanced T1 FLASH, and 45 % and 48 % with T1 3D Dixon VIBE in transverse and coronal orientation, respectively. Staging accuracy with T2 BLADE was significantly higher than with non-enhanced T1 FLASH and with T1 3D Dixon VIBE in transverse and coronal orientations (p < 0.0024). T2 HASTE had a significantly higher T-staging accuracy than transverse T1 3D-Dixon-VIBE (p < 0.0024). Transverse T2 BLADE images provide the highest accuracy for local tumour staging and should therefore be included in dedicated thoracic PET/MR protocols. As T1 3D Dixon VIBE images acquired for attenuation correction performed significantly worse, this sequence cannot be considered sufficiently accurate for local tumour staging in the thorax. (orig.)

  10. The OMERACT psoriatic arthritis magnetic resonance imaging scoring system (PsAMRIS): definitions of key pathologies, suggested MRI sequences, and preliminary scoring system for PsA Hands

    DEFF Research Database (Denmark)

    Østergaard, Mikkel; McQueen, Fiona; Wiell, Charlotte

    2009-01-01

    This article describes a preliminary OMERACT psoriatic arthritis magnetic resonance image scoring system (PsAMRIS) for evaluation of inflammatory and destructive changes in PsA hands, which was developed by the international OMERACT MRI in inflammatory arthritis group. MRI definitions of important...... pathologies in peripheral PsA and suggestions concerning appropriate MRI sequences for use in PsA hands are also provided....

  11. 1D and 2D diffusion pore imaging on a preclinical MR system using adaptive rephasing: Feasibility and pulse sequence comparison

    Science.gov (United States)

    Bertleff, Marco; Domsch, Sebastian; Laun, Frederik B.; Kuder, Tristan A.; Schad, Lothar R.

    2017-05-01

    Diffusion pore imaging (DPI) has recently been proposed as a means to acquire images of the average pore shape in an image voxel or region of interest. The highly asymmetric gradient scheme of its sequence makes it substantially demanding in terms of the hardware of the NMR system. The aim of this work is to show the feasibility of DPI on a preclinical 9.4 T animal scanner. Using water-filled capillaries with an inner radius of 10 μm, four different variants of the DPI sequence were compared in 1D and 2D measurements. The pulse sequences applied cover the basic implementation using one long and one temporally narrow gradient pulse, a CPMG-like variant with multiple refocusing RF pulses as well as two variants splitting up the long gradient and distributing it on either side of the refocusing pulse. Substantial differences between the methods were found in terms of signal-to-noise ratio, contrast, blurring, deviations from the expected results and sensitivity to gradient imperfections. Each of the tested sequences was found to produce characteristic gradient mismatches dependent on the absolute value, direction and sign of the applied q-value. Read gradients were applied to compensate these mismatches translating them into time shifts, which enabled 1D DPI yielding capillary radius estimations within the tolerances specified by the manufacturer. For a successful DPI application in 2D, a novel gradient amplitude adaption scheme was implemented to correct for the occurring time shifts. Using this adaption, higher conformity to the expected pore shape, reduced blurring and enhanced contrast were achieved. Images of the phantom's pore shape could be acquired with a nominal resolution of 2.2 μm.

  12. Characterizing cross-subject spatial interaction patterns in functional magnetic resonance imaging studies: A two-stage point-process model.

    Science.gov (United States)

    Lee, Adél; Särkkä, Aila; Madhyastha, Tara M; Grabowski, Thomas J

    2017-11-01

    We develop a two-stage spatial point process model that introduces new characterizations of activation patterns in multisubject functional Magnetic Resonance Imaging (fMRI) studies. Conventionally multisubject fMRI methods rely on combining information across subjects one voxel at a time in order to identify locations of peak activation in the brain. The two-stage model that we develop here addresses shortcomings of standard methods by explicitly modeling the spatial structure of functional signals and recognizing that corresponding cross-subject functional signals can be spatially misaligned. In our first stage analysis, we introduce a marked spatial point process model that captures the spatial features of the functional response and identifies a configuration of activation units for each subject. The locations of these activation units are used as input for the second stage model. The point process model of the second stage analysis is developed to characterize multisubject activation patterns by estimating the strength of cross-subject interactions at different spatial ranges. The model uses spatial neighborhoods to account for the cross-subject spatial misalignment in corresponding functional units. We applied our methods to an fMRI study of 21 individuals who performed an attention test. We identified four brain regions that are involved in the test and found that our model results agree well with our understanding of how these regions engage with the tasks performed during the attention test. Our results highlighted that cross-subject interactions are stronger in brain areas that have a more specific function in performing the experimental tasks than in other areas. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Inaudible functional MRI using a truly mute gradient echo sequence

    Energy Technology Data Exchange (ETDEWEB)

    Marcar, V.L. [University of Zurich, Department of Psychology, Neuropsychology, Treichlerstrasse 10, 8032 Zurich (Switzerland); Girard, F. [GE Medical Systems SA, 283, rue de la Miniere B.P. 34, 78533 Buc Cedex (France); Rinkel, Y.; Schneider, J.F.; Martin, E. [University Children' s Hospital, Neuroradiology and Magnetic Resonance, Department of Diagnostic Imaging, Steinwiesstrasse 75, 8032 Zurich (Switzerland)

    2002-11-01

    We performed functional MRI experiments using a mute version of a gradient echo sequence on adult volunteers using either a simple visual stimulus (flicker goggles: 4 subjects) or an auditory stimulus (music: 4 subjects). Because the mute sequence delivers fewer images per unit time than a fast echo planar imaging (EPI) sequence, we explored our data using a parametric ANOVA test and a non-parametric Wilcoxon-Mann-Whitney test in addition to performing a cross-correlation analysis. All three methods were in close agreement regarding the location of the BOLD contrast signal change. We demonstrated that, using appropriate statistical analysis, functional MRI using an MR sequence that is acoustically inaudible to the subject is feasible. Furthermore compared with the ''silent'' event-related procedures involving an EPI protocol, our mGE protocol compares favourably with respect to experiment time and the BOLD signal. (orig.)

  14. Single-subject-based whole-brain MEG slow-wave imaging approach for detecting abnormality in patients with mild traumatic brain injury.

    Science.gov (United States)

    Huang, Ming-Xiong; Nichols, Sharon; Baker, Dewleen G; Robb, Ashley; Angeles, Annemarie; Yurgil, Kate A; Drake, Angela; Levy, Michael; Song, Tao; McLay, Robert; Theilmann, Rebecca J; Diwakar, Mithun; Risbrough, Victoria B; Ji, Zhengwei; Huang, Charles W; Chang, Douglas G; Harrington, Deborah L; Muzzatti, Laura; Canive, Jose M; Christopher Edgar, J; Chen, Yu-Han; Lee, Roland R

    2014-01-01

    Traumatic brain injury (TBI) is a leading cause of sustained impairment in military and civilian populations. However, mild TBI (mTBI) can be difficult to detect using conventional MRI or CT. Injured brain tissues in mTBI patients generate abnormal slow-waves (1-4 Hz) that can be measured and localized by resting-state magnetoencephalography (MEG). In this study, we develop a voxel-based whole-brain MEG slow-wave imaging approach for detecting abnormality in patients with mTBI on a single-subject basis. A normative database of resting-state MEG source magnitude images (1-4 Hz) from 79 healthy control subjects was established for all brain voxels. The high-resolution MEG source magnitude images were obtained by our recent Fast-VESTAL method. In 84 mTBI patients with persistent post-concussive symptoms (36 from blasts, and 48 from non-blast causes), our method detected abnormalities at the positive detection rates of 84.5%, 86.1%, and 83.3% for the combined (blast-induced plus with non-blast causes), blast, and non-blast mTBI groups, respectively. We found that prefrontal, posterior parietal, inferior temporal, hippocampus, and cerebella areas were particularly vulnerable to head trauma. The result also showed that MEG slow-wave generation in prefrontal areas positively correlated with personality change, trouble concentrating, affective lability, and depression symptoms. Discussion is provided regarding the neuronal mechanisms of MEG slow-wave generation due to deafferentation caused by axonal injury and/or blockages/limitations of cholinergic transmission in TBI. This study provides an effective way for using MEG slow-wave source imaging to localize affected areas and supports MEG as a tool for assisting the diagnosis of mTBI.

  15. Single-subject-based whole-brain MEG slow-wave imaging approach for detecting abnormality in patients with mild traumatic brain injury

    Directory of Open Access Journals (Sweden)

    Ming-Xiong Huang

    2014-01-01

    Full Text Available Traumatic brain injury (TBI is a leading cause of sustained impairment in military and civilian populations. However, mild TBI (mTBI can be difficult to detect using conventional MRI or CT. Injured brain tissues in mTBI patients generate abnormal slow-waves (1–4 Hz that can be measured and localized by resting-state magnetoencephalography (MEG. In this study, we develop a voxel-based whole-brain MEG slow-wave imaging approach for detecting abnormality in patients with mTBI on a single-subject basis. A normative database of resting-state MEG source magnitude images (1–4 Hz from 79 healthy control subjects was established for all brain voxels. The high-resolution MEG source magnitude images were obtained by our recent Fast-VESTAL method. In 84 mTBI patients with persistent post-concussive symptoms (36 from blasts, and 48 from non-blast causes, our method detected abnormalities at the positive detection rates of 84.5%, 86.1%, and 83.3% for the combined (blast-induced plus with non-blast causes, blast, and non-blast mTBI groups, respectively. We found that prefrontal, posterior parietal, inferior temporal, hippocampus, and cerebella areas were particularly vulnerable to head trauma. The result also showed that MEG slow-wave generation in prefrontal areas positively correlated with personality change, trouble concentrating, affective lability, and depression symptoms. Discussion is provided regarding the neuronal mechanisms of MEG slow-wave generation due to deafferentation caused by axonal injury and/or blockages/limitations of cholinergic transmission in TBI. This study provides an effective way for using MEG slow-wave source imaging to localize affected areas and supports MEG as a tool for assisting the diagnosis of mTBI.

  16. Wideband arrhythmia-Insensitive-rapid (AIR) pulse sequence for cardiac T1 mapping without image artifacts induced by an implantable-cardioverter-defibrillator.

    Science.gov (United States)

    Hong, KyungPyo; Jeong, Eun-Kee; Wall, T Scott; Drakos, Stavros G; Kim, Daniel

    2015-08-01

    To develop and evaluate a wideband arrhythmia-insensitive-rapid (AIR) pulse sequence for cardiac T1 mapping without image artifacts induced by implantable-cardioverter-defibrillator (ICD). We developed a wideband AIR pulse sequence by incorporating a saturation pulse with wide frequency bandwidth (8.9 kHz) to achieve uniform T1 weighting in the heart with ICD. We tested the performance of original and "wideband" AIR cardiac T1 mapping pulse sequences in phantom and human experiments at 1.5 Tesla. In five phantoms representing native myocardium and blood and postcontrast blood/tissue T1 values, compared with the control T1 values measured with an inversion-recovery pulse sequence without ICD, T1 values measured with original AIR with ICD were considerably lower (absolute percent error > 29%), whereas T1 values measured with wideband AIR with ICD were similar (absolute percent error T1 values measured with original AIR without ICD, T1 measured with original AIR with ICD was significantly lower (absolute percent error > 10.1%), whereas T1 measured with wideband AIR with ICD was similar (absolute percent error T1 mapping without significant image artifacts induced by ICD. © 2015 Wiley Periodicals, Inc.

  17. Sequence variations of the pancreatic islet/liver glucose transporter (GLUT2) gene in Japanese subjects with noninsulin dependent diabetes mellitus

    Energy Technology Data Exchange (ETDEWEB)

    Matsubara, Atsushi; Tanizawa, Yukio; Matsutani, Akira [Yamaguchi Univ. School of Medicine (Japan)] [and others

    1995-10-01

    To assess the genetic susceptibility to noninsulin-dependent diabetes mellitus (NIDDM) in Japanese subjects, we investigated the role of GLUT2 gene defects in patients with NIDDM. When the allelic frequency of a simple tandem repeat polymorphism in the GLUT2 gene was compared, the allele with 155 base pairs was more common in NIDDM patients (n = 99) than in controls (n = 89; 5.1% v. 0.6%; P = 0.0118, by Fisher`s exact test), whereas this was not significant after the correction for multiple comparisons. To directly identify mutations, we then analyzed each of 11 exons by the polymerase chain reaction-single strand conformation polymorphism analysis in 60 NIDDM patients. We found 2 missense mutations in exon 3: CCC{r_arrow}CTC (Pro{sup 68}{r_arrow}Leu) in 1 patient and ACT{r_arrow}ATT (Thr{sup 110}{r_arrow}Ile) in 3 patients, all in the heterozygous state. These mutations were found in 60 control subjects. To evaluate the significance of the Pro{sup 68}{r_arrow}Leu mutation, the family members of the proband were studied. The mutation did not appear to be associated with the disease or other clinical parameters including change in immunoreactive insulin/change in plasma glucose or oral glucose load. The other mutation (Thr{sup 110}{r_arrow}Ile) is known to be functionally insignificant. We identified 4 additional nucleotide changes, all of which appeared to be silent. We concluded that the mutations in the GLUT2 gene were not major determinants of genetic susceptibility to NIDDM in Japanese. 34 refs., 2 figs., 3 tabs.

  18. Cidades-imagem: afirmações e enfrentamentos às políticas da subjetividade Cities-image: affirmations and interrogations to subjectivity's politics

    Directory of Open Access Journals (Sweden)

    Ana Cabral Rodrigues

    2010-12-01

    Full Text Available Neste trabalho propomos articular subjetividades e espaços através de imagens, estas compreendidas no sentido que delas podemos apreender a partir dos escritos do filósofo alemão Walter Benjamin. Em Imagens do Pensamento, Benjamin nos convida a ler-ver imagens, não enquanto matéria a ser decifrada, tampouco como mera representação do mundo, mas como força que pode produzir estranhamento a partir de sentidos que não se completam, que não se encerram em si mesmos, não totalizam. Sentidos incompletos que saltam a partir de seus encontros, de suas montagens. Teceremos, assim, articulações entre subjetividades e espaços através de algumas imagens da Paris de Haussmann, das provocadoras cidades invisíveis de Ítalo Calvino e da porosidade de Nápoles, narrada por Walter Benjamin. As questões que permeiam este trabalho são: o que as cidades-imagem afirmam e como elas interpelam o campo de estudos da subjetividade.In this essay we intend to articulate subjectivities and spaces through images, in the sense in which they may be apprehended based on the writings of Walter Benjamin. In Images of thought, Benjamin invites us to read-see images, not as matter to be deciphered, nor as mere representation of the world, but as a force that might produce an estrangement that emerge from senses that do not reach completeness, that are not enclosed in themselves, that do not constitute totalities. Incomplete senses that emerge from encounters, from collages. Therefore, we shall articulate subjectivities and spaces through images by Haussmann's Paris, the provoking invisible cities by Italo Calvino and by Naples' porosity, narrated by Walter Benjamin. The questions that permeate this work are: what do the cities-image affirm, and how do they interrogate the field of studies of subjectivity.

  19. Potential influence of Gadolinium contrast on image segmentation in MR-based attenuation correction with Dixon sequences in whole-body 18F-FDG PET/MR.

    Science.gov (United States)

    Ruhlmann, Verena; Heusch, Philipp; Kühl, Hilmar; Beiderwellen, Karsten; Antoch, Gerald; Forsting, Michael; Bockisch, Andreas; Buchbender, Christian; Quick, Harald H

    2016-04-01

    To evaluate the influence of Gadolinium contrast agent on image segmentation in magnetic resonance (MR)-based attenuation correction (AC) with four-segment dual-echo time Dixon-sequences in whole-body [18F]-fluorodeoxyglucose positron emission tomography (PET)/MR imaging, and to analyze the consecutive effect on standardized uptake value (SUV). Hybrid imaging with an integrated PET/MR system was performed in 30 oncological patients. AC was based on MR imaging with a Dixon sequence with subsequent automated image segmentation. AC maps (µmaps) were acquired and reconstructed prior to (µmap-gd) and after (µmap+gd) Gd-contrast agent application. For quantification purposes, the SUV of organs and tumors based on both µmaps were compared. Tissue classification based on µmap-gd was correct in 29/30 patients; based on µmap+gd, the brain was falsely classified as fat in 12/30 patients with significant underestimation of SUV. In all cancerous lesions, tissue segmentation was correct. All concordant µmaps-gd/+gd resulted in no significant difference in SUV. In PET/MR, Gd-contrast agent potentially influences fat/water separation in Dixon-sequences of the head with above-average false tissue segmentation and an associated underestimation of SUV. Thus, MR-based AC should be acquired prior to Gd-contrast agent application. Additionally, integrating the MR-based AC maps into the reading-routine in PET/MR is recommended to avoid interpretation errors in cases where tissue segmentation fails.

  20. Next-generation-sequencing-based identification of familial hypercholesterolemia-related mutations in subjects with increased LDL-C levels in a latvian population.

    Science.gov (United States)

    Radovica-Spalvina, Ilze; Latkovskis, Gustavs; Silamikelis, Ivars; Fridmanis, Davids; Elbere, Ilze; Ventins, Karlis; Ozola, Guna; Erglis, Andrejs; Klovins, Janis

    2015-09-28

    Familial hypercholesterolemia (FH) is one of the commonest monogenic disorders, predominantly inherited as an autosomal dominant trait. When untreated, it results in early coronary heart disease. The vast majority of FH remains undiagnosed in Latvia. The identification and early treatment of affected individuals remain a challenge worldwide. Most cases of FH are caused by mutations in one of four genes, APOB, LDLR, PCSK9, or LDLRAP1. The spectrum of disease-causing variants is very diverse and the variation detection panels usually used in its diagnosis cover only a minority of the disease-causing gene variants. However, DNA-based tests may provide an FH diagnosis for FH patients with no physical symptoms and with no known family history of the disease. Here, we evaluate the use of targeted next-generation sequencing (NGS) to identify cases of FH in a cohort of patients with coronary artery disease (CAD) and individuals with abnormal low-density lipoprotein-cholesterol (LDL-C) levels. We used targeted amplification of the coding regions of LDLR, APOB, PCSK9, and LDLRAP1, followed by NGS, in 42 CAD patients (LDL-C, 4.1-7.2 mmol/L) and 50 individuals from a population-based cohort (LDL-C, 5.1-9.7 mmol/L). In total, 22 synonymous and 31 nonsynonymous variants, eight variants in close proximity (10 bp) to intron-exon boundaries, and 50 other variants were found. We identified four pathogenic mutations (p.(Arg3527Gln) in APOB, and p.(Gly20Arg), p.(Arg350*), and c.1706-10G > A in LDLR) in seven patients (7.6 %). Three possible pathogenic variants were also found in four patients. NGS-based methods can be used to detect FH in high-risk individuals when they do not meet the defined clinical criteria.

  1. Correlation between podoplanin expression and extracapsular spread in squamous cell carcinoma of the oral cavity using subjective immunoreactivity scores and semiquantitative image analysis.

    Science.gov (United States)

    Mermod, Maxime; Bongiovanni, Massimo; Petrova, Tatiana V; Dubikovskaya, Elena A; Simon, Christian; Tolstonog, Genrich; Monnier, Yan

    2017-01-01

    The correlation between podoplanin expression and extracapsular spread in head and neck squamous cell carcinoma (HNSCC) has never been reported. The purpose of this study was to assess the predictive value of podoplanin expression for this parameter. Subjective immunoreactivity scores and semiquantitative image analysis of podoplanin expression were performed in 67 patients with primary oral squamous cell carcinoma and in their corresponding lymph nodes. Neck classification showed 34 cases (51%) of pN0 and 33 cases (49%) of pN+. Correlation between the levels of podoplanin expression and the histopathological data was established. In lymph nodes, a high level of podoplanin expression correlated with the presence of extracapsular spread by multivariate analysis (p = .03). A strong correlation between subjective and semiquantitative image analysis was observed (r = 0.77; p < .001). A high level of podoplanin expression in lymph node metastases of oral squamous cell carcinoma is independently associated with extracapsular spread. © 2016 Wiley Periodicals, Head Neck 39: 98-108, 2017. © 2016 Wiley Periodicals, Inc.

  2. Simple anthropometric measures correlate with metabolic risk indicators as strongly as magnetic resonance imaging-measured adipose tissue depots in both HIV-infected and control subjects.

    Science.gov (United States)

    Scherzer, Rebecca; Shen, Wei; Bacchetti, Peter; Kotler, Donald; Lewis, Cora E; Shlipak, Michael G; Heymsfield, Steven B; Grunfeld, Carl

    2008-06-01

    Studies in persons without HIV infection have compared percentage body fat (%BF) and waist circumference as markers of risk for the complications of excess adiposity, but only limited study has been conducted in HIV-infected subjects. We compared anthropometric and magnetic resonance imaging (MRI)-based adiposity measures as correlates of metabolic complications of adiposity in HIV-infected and control subjects. The study was a cross-sectional analysis of 666 HIV-positive and 242 control subjects in the Fat Redistribution and Metabolic Change in HIV Infection (FRAM) study assessing body mass index (BMI), waist (WC) and hip (HC) circumferences, waist-to-hip ratio (WHR), %BF, and MRI-measured regional adipose tissue. Study outcomes were 3 metabolic risk variables [homeostatic model assessment (HOMA), triglycerides, and HDL cholesterol]. Analyses were stratified by sex and HIV status and adjusted for demographic, lifestyle, and HIV-related factors. In HIV-infected and control subjects, univariate associations with HOMA, triglycerides, and HDL were strongest for WC, MRI-measured visceral adipose tissue, and WHR; in all cases, differences in correlation between the strongest measures for each outcome were small (r subjects.

  3. Hourly and Spatial Analysis of Degrees of Congestion in the Observation Camera Scene by Accumulating Local Changes in the Image Sequence

    Science.gov (United States)

    Niwakawa, Makoto; Onda, Toshikazu

    We can see a lot of observation cameras at public or private facilities such as stations, halls, shopping malls, hallways and gates. Some janitors of the facilities want to detect and investigate passing people or congestion existences in the camera scene. In order to respond to these requests, we extracted moving areas in the image and accumulated these data and then displayed them on the monitor. Consequently, we obtained spatial distributions and hourly changes of congestion in the observation camera scene. To extract moving areas, we estimated the differences of correlation value of segmented small windows in the image. This paper describes our procedure to analyze the congestion from the image sequence of observation camera, and some experimental results.

  4. Images

    Data.gov (United States)

    National Aeronautics and Space Administration — Images for the website main pages and all configurations. The upload and access points for the other images are: Website Template RSW images BSCW Images HIRENASD...

  5. [Determination of iodine content in the left ventricular myocardium of healthy subjects using dual-source dual-energy CT myocardial first perfusion imaging: a preliminary study].

    Science.gov (United States)

    Chen, Z X; Wang, G; Liang, L; Lu, X R; Guo, Q H; Zhai, Y N; Shi, X N

    2017-05-24

    Objective: To analyze the normal value of the iodine content in the left ventricular myocardium of healthy subjects and to observe if there is a segmental differences on iodine distribution by using the second generation dual-source dual-energy computed tomography myocardial first perfusion imaging. Methods: In this retrospective study, 42 healthy subjects, who admitted to our department between January to June 2016, with normal second generation dual-source dual-energy computed tomography and coronary CT angioghphy (CTA), electrocardiogram (ECG) results, normal cardiac, hepatic, renal function, normal myocardial enzymes results were enrolled, data from 38 out of 42 subjects with satisfactory image quality were analyzed using Siemens Dual Energy-Heart PBV image processing software.In accordance with the standards of the American Heart Association myocardial 17 fractionation method, content of iodine was measured at different segmental left ventricular myocardium and aorta (left coronary artery from the opening level). The standardized containing iodine value (nIC) was calculated. Results: The iodine content of left ventricular myocardium in normal subjects was 3.1-7.8 mg/ml.The nIC of myocardium from 1st to 17th segments was 0.28±0.06, 0.31±0.07, 0.30±0.07, 0.30±0.04, 0.28±0.04, 0.29±0.05, 0.29±0.01, 0.30±0.07, 0.31±0.07, 0.27±0.06, 0.28±0.08, 0.28±0.07, 0.29±0.08, 0.31±0.07, 0.27±0.06, 0.29±0.06 and 0.21±0.07, respectively.The nIC of the 17th segment was the lowest and was significantly lower than in other segments (all PnIC was similar among the rest 16 segments (all P>0.05). Conclusion: The normal iodine content range in left ventricle myocardium is 3.1-7.8 mg/ml, and the lowest iodine content is detected in the apex and which is significantly lower than the other left ventricular segments.

  6. The combined effect of subjective body image and body mass index (distorted body weight perception) on suicidal ideation.

    Science.gov (United States)

    Shin, Jaeyong; Choi, Young; Han, Kyu-Tae; Cheon, Sung-Youn; Kim, Jae-Hyun; Lee, Sang Gyu; Park, Eun-Cheol

    2015-03-01

    Mental health disorders and suicide are an important and growing public health concern in Korea. Evidence has shown that both globally and in Korea, obesity is associated with an increased risk of developing some psychiatric disorders. Therefore, we examined the association between distorted body weight perception (BWP) and suicidal ideation. Data were obtained from the 2007-2012 Korea National Health and Nutritional Evaluation Survey (KNHANES), an annual cross-sectional nationwide survey that included 14 276 men and 19 428 women. Multiple logistic regression analyses were conducted to investigate the associations between nine BWP categories, which combined body image (BI) and body mass index (BMI) categories, and suicidal ideation. Moreover, the fitness of our models was verified using the Akaike information criterion. Consistent with previous studies, suicidal ideation was associated with marital status, household income, education level, and perceived health status in both genders. Only women were significantly more likely to have distorted BWP; there was no relationship among men. In category B1 (low BMI and normal BI), women (odds ratio [OR], 2.25; 95% confidence interval [CI], 1.48 to 3.42) were more likely to express suicidal ideation than women in category B2 (normal BMI and normal BI) were. Women in overweight BWP category C2 (normal BMI and fat BI) also had an increased OR for suicidal ideation (OR, 2.25; 95% CI, 1.48 to 3.42). Those in normal BWP categories were not likely to have suicidal ideation. Among women in the underweight BWP categories, only the OR for those in category A2 (normal BMI and thin BI) was significant (OR, 1.34; 95% CI, 1.13 to 1.59). Distorted BWP should be considered an important factor in the prevention of suicide and for the improvement of mental health among Korean adults, especially Korean women with distorted BWPs.

  7. The Combined Effect of Subjective Body Image and Body Mass Index (Distorted Body Weight Perception on Suicidal Ideation

    Directory of Open Access Journals (Sweden)

    Jaeyong Shin

    2015-03-01

    Full Text Available Objectives: Mental health disorders and suicide are an important and growing public health concern in Korea. Evidence has shown that both globally and in Korea, obesity is associated with an increased risk of developing some psychiatric disorders. Therefore, we examined the association between distorted body weight perception (BWP and suicidal ideation. Methods: Data were obtained from the 2007-2012 Korea National Health and Nutritional Evaluation Survey (KNHANES, an annual cross-sectional nationwide survey that included 14 276 men and 19 428 women. Multiple logistic regression analyses were conducted to investigate the associations between nine BWP categories, which combined body image (BI and body mass index (BMI categories, and suicidal ideation. Moreover, the fitness of our models was verified using the Akaike information criterion. Results: Consistent with previous studies, suicidal ideation was associated with marital status, household income, education level, and perceived health status in both genders. Only women were significantly more likely to have distorted BWP; there was no relationship among men. In category B1 (low BMI and normal BI, women (odds ratio [OR], 2.25; 95% confidence interval [CI], 1.48 to 3.42 were more likely to express suicidal ideation than women in category B2 (normal BMI and normal BI were. Women in overweight BWP category C2 (normal BMI and fat BI also had an increased OR for suicidal ideation (OR, 2.25; 95% CI, 1.48 to 3.42. Those in normal BWP categories were not likely to have suicidal ideation. Among women in the underweight BWP categories, only the OR for those in category A2 (normal BMI and thin BI was significant (OR, 1.34; 95% CI, 1.13 to 1.59. Conclusions: Distorted BWP should be considered an important factor in the prevention of suicide and for the improvement of mental health among Korean adults, especially Korean women with distorted BWPs.

  8. Hypermetabolism of compensatory laryngeal muscles in unilateral vocal cord palsy: comparison study between speech and silence with normal subjects by co-registered PET-CT fusion images

    Energy Technology Data Exchange (ETDEWEB)

    Pai, Moon Sun; Kim, Hyon Kyong; Kim, Han Su [Ewha Womans University College of Medicine, Seoul (Korea, Republic of)

    2006-02-15

    There are a few case report on asymmetric vocal cord uptake on FDG-PET in patients with unilateral vocal cord paralysis, which could be a potential pitfall in the interpretation of FDG-PET images. We evaluated the metabolic activity of laryngeal muscles of patients with unilateral vocal cord paralysis in comparison to normal controls during both speech and silence. Eleven patients with unilateral vocal cord palsy (thyroidectomy=7, lung cancer=1, other=3) and 12 normal controls underwent FDG-PET with usual protocol. They were divided into two groups respectively; one group read books aloud for 20 minutes (phonation group) and the other kept silence (non-phonation groups) after FDG injection. Recent neck CT scan were co-registered with FDG-PET to produce PET-CT fusion images to elaborate small laryngeal muscles. In patients with unilateral vocal cord palsy, contralateral non-paralyzed vocal cord showed hypermetabolism mainly on thyroarytenoid muscle, more intensely with phonation group (SUV=5.88{+-}2.65) than with non-phonation group (SUV=2.30{+-}0.39). Normal control subjects showed hypermetabolism (3.68{+-} 0.96) in interarytenoid muscle and symmetric mild hypermetabolism in both lateral cricoarytenoid muscles in only phonation group. FDG-PET with fusion images using CT scan in patients with unilateral vocal cord paralysis showed hypermetabolism of contralateral non-paralyzed thyroarytedoid muscle, suggesting compensatory action during phonation. Phonation during FDG-PET study enhanced FDG uptake on different laryngeal muscles between patients with unilateral vocal cord paralysis and normal subjects.

  9. Hypermetabolism of compensatory laryngeal muscles in unilateral vocal cord palsy: comparison study between speech and silence with normal subjects by co-registered PET-CT fusion images

    Energy Technology Data Exchange (ETDEWEB)

    Pai, Moon Sun; Kim, Hyon Kyong; Kim, Han Su; Chung, Sung Min [College of Medicine, Ewha Womans University, Seoul (Korea, Republic of)

    2005-07-01

    There are a few case reports on asymmetric vocal cord uptake on FDG-PET in patients with unilateral vocal cord paralysis, which could be a potential pitfall in the interpretation of FDG-PET images. We evaluated the metabolic activity of laryngeal muscles of patients with unilateral vocal cord paralysis in comparison to normal controls during both speech and silence. Eleven patients with iatrogenic unilateral vocal cord palsy(thyroidectomy 7, lung cancer = 1, others = 3) and 12 normal controls underwent FDG-PET with usual protocol. They were divided into two groups respectively; one group read books aloud for 20 minutes (phonation group) and the other kept silence (non-phonation groups) after FDG injection. Recent neck CT scan were co-registered with FDG-PET to produce PET-CT fusion images to elaborate small laryngeal muscles. In patients with unilateral vocal cord palsy, contralateral non-paralyzed vocal cord showed increased FDG uptake, more intense with phonation group (SUV =5.88, n =5) than non-phonation group (SUV =2.33, n =6) --mainly on thyroarytenoid muscle. Normal control subjects showed symmetric mildly increased FDG uptake (SUV=1.92, n=6) only in phonation group, which was significantly low against patient groups and was localized in lateral cricoarytenoid muscle. Hypermetabolism of contralateral thyroarytenoid muscle in patients with unilateral vocal cord paralysis could be encountered during FDG-PET imaging even with keeping silence. Phonation during FDG-PET study enhance FDG uptake on different laryngeal muscles between unilateral vocal cord paralysis and normal subjects.

  10. Clinical application of controlled aliasing in parallel imaging results in a higher acceleration (CAIPIRINHA)-volumetric interpolated breathhold (VIBE) sequence for gadoxetic acid-enhanced liver MR imaging.

    Science.gov (United States)

    Yu, Mi Hye; Lee, Jeong Min; Yoon, Jeong-Hee; Kiefer, Berthold; Han, Joon Koo; Choi, Byung-Ihn

    2013-11-01

    To determine whether a controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA) technique can improve the image quality of three-dimensional (3D), T1-weighted gradient echo (T1w-GRE) imaging compared with the use of a standard, parallel acquisition technique (PAT). Sixty-four patients who underwent liver MR on a 3 Tesla (T) scanner, were included in this study. Twenty minutes after the injection of 0.025 mmole/kg of gadoxetic acid, 3D T1w-GRE imaging (volumetric interpolated breathhold examination [VIBE]) was acquired twice using a generalized autocalibrating partially parallel acquisition (384 × 250 matrix, acceleration factor [AF] of 2) and a CAIPIRINHA (384 × 380 matrix, AF of 4), respectively. Qualitative image analysis was performed for two image sets. CAIPIRINHA-VIBE showed better hepatic vessel clarity and lesion conspicuity than standard VIBE (P spatial resolution, T1-weighted imaging with better image quality compared with a standard VIBE. Copyright © 2013 Wiley Periodicals, Inc.

  11. Comprehensive small animal imaging strategies on a clinical 3 T dedicated head MR-scanner; adapted methods and sequence protocols in CNS pathologies.

    Directory of Open Access Journals (Sweden)

    Deepu R Pillai

    Full Text Available BACKGROUND: Small animal models of human diseases are an indispensable aspect of pre-clinical research. Being dynamic, most pathologies demand extensive longitudinal monitoring to understand disease mechanisms, drug efficacy and side effects. These considerations often demand the concomitant development of monitoring systems with sufficient temporal and spatial resolution. METHODOLOGY AND RESULTS: This study attempts to configure and optimize a clinical 3 Tesla magnetic resonance scanner to facilitate imaging of small animal central nervous system pathologies. The hardware of the scanner was complemented by a custom-built, 4-channel phased array coil system. Extensive modification of standard sequence protocols was carried out based on tissue relaxometric calculations. Proton density differences between the gray and white matter of the rodent spinal cord along with transverse relaxation due to magnetic susceptibility differences at the cortex and striatum of both rats and mice demonstrated statistically significant differences. The employed parallel imaging reconstruction algorithms had distinct properties dependent on the sequence type and in the presence of the contrast agent. The attempt to morphologically phenotype a normal healthy rat brain in multiple planes delineated a number of anatomical regions, and all the clinically relevant sequels following acute cerebral ischemia could be adequately characterized. Changes in blood-brain-barrier permeability following ischemia-reperfusion were also apparent at a later time. Typical characteristics of intra-cerebral haemorrhage at acute and chronic stages were also visualized up to one month. Two models of rodent spinal cord injury were adequately characterized and closely mimicked the results of histological studies. In the employed rodent animal handling system a mouse model of glioblastoma was also studied with unequivocal results. CONCLUSIONS: The implemented customizations including extensive

  12. Variable Flip Angle 3D Fast Spin-Echo Sequence Combined with Outer Volume Suppression for Imaging Trabecular Bone Structure of the Proximal Femur

    Science.gov (United States)

    Han, Misung; Chiba, Ko; Banerjee, Suchandrima; Carballido-Gamio, Julio; Krug, Roland

    2014-01-01

    Purpose To demonstrate the feasibility of using a variable flip angle 3D fast spin-echo (3D VFA-FSE) sequence combined with outer volume suppression for imaging of trabecular bone structure at the proximal femur in vivo at 3T. Materials and Methods The 3D VFA-FSE acquisition was optimized to minimize blurring and to provide high signal-to-noise ratio (SNR) from bone marrow. Outer volume suppression was achieved by applying three quadratic-phase radio-frequency pulses. The SNR and trabecular bone structures from 3D VFA-FSE was compared with those from previously demonstrated multiple-acquisition 3D balanced steady-state free precision (bSSFP) using theoretical simulations, ex vivo experiments, and in vivo experiments. Results Our simulation demonstrated that 3D VFA-FSE can provide at least 35% higher SNR than 3D bSSFP, which was confirmed by the ex vivo and in vivo experiments. The ex vivo experiments demonstrated a good correlation and agreement between bone structural paramters obtained with the two sequences. The proposed sequence depicted trabecular bone structure at the proxiaml femur in vivo well without visible suppression artifacts and provided a mean SNR of 11.0. Conclusion The reduced-FOV 3D VFA-FSE sequence can depict the trabecular bone structure of the proximal femur in vivo with minimal blurring and high SNR efficiency. PMID:24956149

  13. Geometric Feature-Based Facial Expression Recognition in Image Sequences Using Multi-Class AdaBoost and Support Vector Machines

    Directory of Open Access Journals (Sweden)

    Joonwhoan Lee

    2013-06-01

    Full Text Available Facial expressions are widely used in the behavioral interpretation of emotions, cognitive science, and social interactions. In this paper, we present a novel method for fully automatic facial expression recognition in facial image sequences. As the facial expression evolves over time facial landmarks are automatically tracked in consecutive video frames, using displacements based on elastic bunch graph matching displacement estimation. Feature vectors from individual landmarks, as well as pairs of landmarks tracking results are extracted, and normalized, with respect to the first frame in the sequence. The prototypical expression sequence for each class of facial expression is formed, by taking the median of the landmark tracking results from the training facial expression sequences. Multi-class AdaBoost with dynamic time warping similarity distance between the feature vector of input facial expression and prototypical facial expression, is used as a weak classifier to select the subset of discriminative feature vectors. Finally, two methods for facial expression recognition are presented, either by using multi-class AdaBoost with dynamic time warping, or by using support vector machine on the boosted feature vectors. The results on the Cohn-Kanade (CK+ facial expression database show a recognition accuracy of 95.17% and 97.35% using multi-class AdaBoost and support vector machines, respectively.

  14. Comparison of qualitative and quantitative imaging characteristics of [11C]PiB and [18F]flutemetamol in normal control and Alzheimer's subjects.

    Science.gov (United States)

    Mountz, James M; Laymon, Charles M; Cohen, Ann D; Zhang, Zheng; Price, Julie C; Boudhar, Sanaa; McDade, Eric; Aizenstein, Howard J; Klunk, William E; Mathis, Chester A

    2015-01-01

    Neuritic amyloid plaques and neurofibrillary tangles, the hallmark pathologic lesions of Alzheimer's disease, are thought to develop before the symptoms of brain failure are clinically detectable. Imaging methods capable of detecting the presence of neuritic amyloid plaques should improve a clinician's ability to identify Alzheimer's disease during the earliest symptomatic phase and to identify at-risk individuals presymptomatically. Currently the best studied amyloid imaging ligand is [(11)C]Pittsburgh Compound B ([(11)C]PiB). However, the 20-minute half-life of this radiotracer limits its use. This study is designed to evaluate the performance characteristics of [(18)F]flutemetamol and to independently compare results to [(11)C]PiB in the same subjects. Twenty-three subjects, 15 cognitively normal (NL) and 8 with a clinical diagnosis of Alzheimer's Dementia (AD), underwent [(11)C]PiB and [(18)F]flutemetamol PET scans within 28 days of study enrollment. We studied both normal and AD subjects to assess the uptake characteristics across a range of amyloid positivity. Blinded visual reads were conducted by five raters. Correlation analyses were performed between cortical SUVR for the two tracers and also between rater scores and SUVR for each tracer. Overall reader accuracy for classifying scans as amyloid positive or negative was determined for each tracer using SUVR classification as the standard. The linear correlation coefficient between global cortical SUVR for the two tracers was R(2) = 0.85, indicating that both tracers have similar retention characteristics. The two tracers were well correlated for rater-determined AD-like positivity (Cohen κ = 0.82). Averaged visual ratings and global cortical SUVR disagreed on their classification in 2/23 [(11)C]PiB scans and 4/23 [(18)F]flutemetamol scans. [(11)C]PiB and [(18)F]flutemetamol have similar retention characteristics across a range of amyloid negative to positive subjects. Both tracers performed similarly when

  15. Assessment of cardiac function by magnetic resonance imaging: segmented versus real time steady-state free precession sequences

    Energy Technology Data Exchange (ETDEWEB)

    Bezerra, Leonardo Bernardo [Rio Grande do Norte Univ., Natal, RN (Brazil)]. E-mail: warrenhellwind@yahoo.com.br; Marchiori, Edson; Pontes, Paulo V. [Universidade Federal Fluminense, Niteroi, RJ (Brazil). Dept. de Radiologia

    2006-09-15

    Objective: to compare ventricular systolic parameters on segmented and real-time steady-state free precession cine-MRI sequences and ECG-gated MRI in patients presenting or not with cardiac arrhythmias. Materials and methods: ejection fraction and end-diastolic/end-systolic volumes have been compared in 31 patients, 11 presenting with cardiac arrhythmias, and 20 with regular sinus rhythm, using ECG-gated segmented and real-time sequences. The statistical analysis was performed using Pearson's correlation and Bland-Altman agreement plot, with p < 0.01. Results: real-time acquisitions demonstrated endocardial borders blurring effects, but both sequences presented a clear, positive correlation: ejection fraction r = 0.94; end-diastolic volume r = 0.93 and end-systolic volume r 0.98. The assessment of 11 patients with arrhythmias has not demonstrated a statistically significant difference, despite the lower blood pool-myocardial contrast ratio. Conclusion: real-time sequences may be utilized for cardiac function assessment, regardless the patient's cardiac rhythm. (author)

  16. Body image discrepancy and subjective norm as mediators and moderators of the relationship between body mass index and quality of life

    Science.gov (United States)

    Pétré, Benoit; Scheen, André J; Ziegler, Olivier; Donneau, Anne-Françoise; Dardenne, Nadia; Husson, Eddy; Albert, Adelin; Guillaume, Michèle

    2016-01-01

    Background and objective Despite the strength and consistency of the relationship between body mass index (BMI) and quality of life (QoL), a reduction in BMI does not necessarily lead to an improvement in QoL. Between-subject variability indicates the presence of mediators and moderators in the BMI–QoL association. This study aimed to examine the roles of body image discrepancy (BID) and subjective norm (SN) as potential mediators and moderators. Subjects and methods In 2012, 3,016 volunteers (aged ≥18 years) participated in a community-based survey conducted in the French-speaking region of Belgium. Participation was enhanced using a large multimedia campaign (which was supported by a large network of recruiters) that employed the nonstigmatizing slogan, “Whatever your weight, your opinion will count”. Participants were invited to complete a web-based questionnaire on their weight-related experiences. Self-reported measures were used to calculate each participant’s BMI, BID, SN, and QoL (a French obesity-specific QoL questionnaire was used to calculate the participants’ physical dimension of QoL scores [PHY-QoL], psychosocial dimension of QoL scores [PSY/SOC-QoL], and their total scores). The covariates included gender, age, subjective economic status, level of education, household size, and perceived health. The mediation/moderation tests were based on Hayes’ method. Results Tests showed that the relationships between BMI and PHY-QoL, PSY/SOC-QoL, and TOT-QoL were partially mediated by BID in both males and females and by SN in females. Moreover, BID was a moderator of the relationship between BMI and PSY/SOC-QoL in males and females. SN was a moderator of the relationship between BMI and PSY/SOC-QoL in males and between BMI and total scores in males (when used without BID in the models). Conclusion BID and SN should be considered as important factors in obesity management strategies. The study shows that targeting BMI only is not sufficient to

  17. Real-time balanced turbo field echo cine-magnetic resonance imaging evaluation of tongue movements during deglutition in subjects with anterior open bite.

    Science.gov (United States)

    Akin, Erol; Sayin, Mehmet Ozgür; Karaçay, Seniz; Bulakbaşi, Nail

    2006-01-01

    The aim of this study was to evaluate tongue movements in subjects with anterior dental open bites during deglutition by using real-time balanced turbo field echo cine-magnetic resonance imaging. The study included 28 subjects. Two groups were formed according to the presence of anterior open bite (at least 2 mm). The open-bite group (OBG) consisted of 18 patients (14 girls, 4 boys) with a mean age of 14.5 +/- 2.7 years. The control group (CG) consisted of 10 patients (5 girls, 5 boys) with a mean age of 14.5 +/- 2.6 years. We evaluated deglutition during 3 stages: oral (stage 1), pharyngeal (stage 2), and esophageal stage (3). Results indicated that (1) in the OBG, from stage 2 to stage 3, the anterior portion of the tongue dorsum was elevated [corrected] whereas its midportion was lowered [corrected]; (2) in the CG, its posterior portion was lowered [corrected] from stage 2 to stage 3; (3) in the CG, the tongue tip was positioned more posteriorly [corrected] at stage 2 than at stage 1; (4) in the OBG, the tongue tip moved more anteriorly in all stages of deglutition than in the CG. Compensatory tongue functions occur in patients with anterior dental open bites. Dynamic MRI is a promising tool for evaluating swallowing patterns in these patients.

  18. Quantitative assessment of hepatic function: modified look-locker inversion recovery (MOLLI) sequence for T1 mapping on Gd-EOB-DTPA-enhanced liver MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Jeong Hee [Seoul National University Hospital, Department of Radiology, Seoul (Korea, Republic of); Lee, Jeong Min; Han, Joon Koo; Choi, Byung Ihn [Seoul National University Hospital, Department of Radiology, Seoul (Korea, Republic of); Seoul National University College of Medicine, Institute of Radiation Medicine, Jongno-gu, Seoul (Korea, Republic of); Paek, Munyoung [Siemens Healthcare, Seoul (Korea, Republic of)

    2016-06-15

    To determine whether multislice T1 mapping of the liver using a modified look-locker inversion recovery (MOLLI) sequence on gadoxetic acid-enhanced magnetic resonance imaging (MRI) can be used as a quantitative tool to estimate liver function and predict the presence of oesophageal or gastric varices. Phantoms filled with gadoxetic acid were scanned three times using MOLLI sequence to test repeatability. Patients with chronic liver disease or liver cirrhosis who underwent gadoxetic acid-enhanced liver MRI including MOLLI sequence at 3 T were included (n = 343). Pre- and postcontrast T1 relaxation times of the liver (T1liver), changes between pre- and postcontrast T1liver (ΔT1liver), and adjusted postcontrast T1liver (postcontrast T1liver-T1spleen/T1spleen) were compared among Child-Pugh classes. In 62 patients who underwent endoscopy, all T1 parameters and spleen sizes were correlated with varices. Phantom study showed excellent repeatability of MOLLI sequence. As Child-Pugh scores increased, pre- and postcontrast T1liver were significantly prolonged (P < 0.001), and ΔT1liver and adjusted postcontrast T1liver decreased (P< 0.001). Adjusted postcontrast T1liver and spleen size were independently associated with varices (R{sup 2} = 0.29, P < 0.001). T1 mapping of the liver using MOLLI sequence on gadoxetic acid-enhanced MRI demonstrated potential in quantitatively estimating liver function, and adjusted postcontrast T1liver was significantly associated with varices. (orig.)

  19. Automatic detection of the carotid artery boundary on cross-sectional MR image sequences using a circle model guided dynamic programming

    Directory of Open Access Journals (Sweden)

    Brambs Hans

    2011-04-01

    Full Text Available Abstract Background Systematic aerobe training has positive effects on the compliance of dedicated arterial walls. The adaptations of the arterial structure and function are associated with the blood flow-induced changes of the wall shear stress which induced vascular remodelling via nitric oxide delivered from the endothelial cell. In order to assess functional changes of the common carotid artery over time in these processes, a precise measurement technique is necessary. Before this study, a reliable, precise, and quick method to perform this work is not present. Methods We propose a fully automated algorithm to analyze the cross-sectional area of the carotid artery in MR image sequences. It contains two phases: (1 position detection of the carotid artery, (2 accurate boundary identification of the carotid artery. In the first phase, we use intensity, area size and shape as features to discriminate the carotid artery from other tissues and vessels. In the second phase, the directional gradient, Hough transform, and circle model guided dynamic programming are used to identify the boundary accurately. Results We test the system stability using contrast degraded images (contrast resolutions range from 50% to 90%. The unsigned error ranges from 2.86% ± 2.24% to 3.03% ± 2.40%. The test of noise degraded images (SNRs range from 16 to 20 dB shows the unsigned error ranging from 2.63% ± 2.06% to 3.12% ± 2.11%. The test of raw images has an unsigned error 2.56% ± 2.10% compared to the manual tracings. Conclusions We have proposed an automated system which is able to detect carotid artery cross sectional boundary in MRI sequences during heart cycles. The accuracy reaches 2.56% ± 2.10% compared to the manual tracings. The system is stable, reliable and results are reproducible.

  20. Subject-specific finite element modeling of the tibiofemoral joint based on CT, magnetic resonance imaging and dynamic stereo-radiography data in vivo.

    Science.gov (United States)

    Carey, Robert E; Zheng, Liying; Aiyangar, Ameet K; Harner, Christopher D; Zhang, Xudong

    2014-04-01

    In this paper, we present a new methodology for subject-specific finite element modeling of the tibiofemoral joint based on in vivo computed tomography (CT), magnetic resonance imaging (MRI), and dynamic stereo-radiography (DSX) data. We implemented and compared two techniques to incorporate in vivo skeletal kinematics as boundary conditions: one used MRI-measured tibiofemoral kinematics in a nonweight-bearing supine position and allowed five degrees of freedom (excluding flexion-extension) at the joint in response to an axially applied force; the other used DSX-measured tibiofemoral kinematics in a weight-bearing standing position and permitted only axial translation in response to the same force. Verification and comparison of the model predictions employed data from a meniscus transplantation study subject with a meniscectomized and an intact knee. The model-predicted cartilage-cartilage contact areas were examined against "benchmarks" from a novel in situ contact area analysis (ISCAA) in which the intersection volume between nondeformed femoral and tibial cartilage was characterized to determine the contact. The results showed that the DSX-based model predicted contact areas in close alignment with the benchmarks, and outperformed the MRI-based model: the contact centroid predicted by the former was on average 85% closer to the benchmark location. The DSX-based FE model predictions also indicated that the (lateral) meniscectomy increased the contact area in the lateral compartment and increased the maximum contact pressure and maximum compressive stress in both compartments. We discuss the importance of accurate, task-specific skeletal kinematics in subject-specific FE modeling, along with the effects of simplifying assumptions and limitations.

  1. 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

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wen Chao; Choi, Byung Ihn; Han, Joon Koo; Kim, Tae Kyoung; Cho, Soon Gu [Seoul National Univ. College of Medicine, Seoul (Korea, Republic of)

    1997-03-01

    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.

  2. 3D double-echo steady-state sequence assessment of hip joint cartilage and labrum at 3 Tesla: comparative analysis of magnetic resonance imaging and intraoperative data

    Energy Technology Data Exchange (ETDEWEB)

    Schleich, Christoph; Antoch, Gerald [University of Dusseldorf, Department of Diagnostic and Interventional Radiology, Medical Faculty, Duesseldorf (Germany); Hesper, Tobias; Rettegi, Fanni; Zilkens, Christoph; Krauspe, Ruediger; Bittersohl, Bernd [University of Dusseldorf, Department of Orthopedic Surgery, Medical Faculty, Duesseldorf (Germany); Hosalkar, Harish S. [Paradise Valley Hospital, Joint Preservation and Deformity Correction, San Diego, CA (United States); Tri-city Medical Center, Hip Preservation, San Diego, CA (United States)

    2017-10-15

    To assess the diagnostic accuracy of a high-resolution, three-dimensional (3D) double-echo steady-state (DESS) sequence with radial imaging at 3 Tesla (T) for evaluating cartilage and labral alterations in the hip. Magnetic resonance imaging (MRI) data obtained at 3 T, including radially reformatted DESS images and intraoperative data of 45 patients (mean age 42 ± 13.7 years) who underwent hip arthroscopy, were compared. The acetabular cartilage and labrum of the upper hemisphere of the acetabulum and the central femoral head cartilage were evaluated. Sensitivity, specificity, accuracy, and negative and positive predictive values were determined. Sensitivity, specificity and accuracy of the DESS technique were 96.7%, 75% and 93.7% for detecting cartilage lesions and 98%, 76.2% and 95.9% for detecting labral lesions. The positive and negative predictive values for detecting or ruling out cartilage lesions were 96% and 78.9%. For labral lesions, the positive and negative predictive values were 97.5% and 80%. A high-resolution, 3D DESS technique with radial imaging at 3 T demonstrated high accuracy for detecting hip cartilage and labral lesions with excellent interobserver agreement and moderate correlation between MRI and intraoperative assessment. (orig.)

  3. Value of Perineural Edema/Inflammation Detected by Fat Saturation Sequences in Lumbar Magnetic Resonance Imaging of Patients with Unilateral Sciatica

    Energy Technology Data Exchange (ETDEWEB)

    Sirvanci, M.; Duran, C. (Dept. of Radiology, Faculty of Medicine, Istanbul Bilim Univ., Istanbul (Turkey)); Kara, B.; Onat, L.; Ulusoy, O.L.; Mutlu, A. (Dept. of Radiology of Florence Nightingale Hospital, Istanbul (Turkey)); Ozturk, E. (Dept. of Radiology, GATA Haydarpasa Teaching Hospital, Istanbul (Turkey)); Karatoprak, O. (Dept. of Orthopeadic Surgery, Kadikoy Florence Nightingale Hospital, Istanbul (Turkey))

    2009-02-15

    Background: Routine lumbar spine magnetic resonance imaging (MRI) may not show any evidence of the cause of sciatica in some cases. The relationship between nerve root compression detected on lumbar MRI and sciatica is also sometimes uncertain. Purpose: To ascertain whether axial (and, when necessary, sagittal and coronal) short-tau inversion recovery or fat-saturated T2-weighted MRI findings can be used to study the level of sciatica in patients with a non-yielding routine MRI examination. Material and Methods: A total of 215 patients with unilateral sciatica underwent MRI. All patients were asked to complete pain drawing forms describing their pain dermatomal distributions. Perineural edema/inflammation corresponding to the pain location indicated by the pain drawings was sought on short-tau inversion recovery or fat-saturated T2-weighted images. Results: Routine MRI findings revealed that 110 of the 215 patients had nerve root compromise related to the patients' symptoms. Routine MRI could not ascertain the cause of these symptoms in the remaining 105 patients. In 31 (29.5%) of these 105 patients, short-tau inversion recovery or fat-saturated T2-weighted magnetic resonance images revealed perineural edema/inflammation surrounding the nerve roots related to the pain locations indicated in the pain drawings. Conclusion: Axial (and, when required, sagittal and coronal) short-tau inversion recovery or fat-saturated T2-weighted magnetic resonance images may be helpful for revealing additional findings in cases of unexplained sciatica in standard magnetic resonance imaging. However, the value of this imaging may be not great enough to justify routine use of these additional sequences to study the level of sciatica

  4. Prenatal imaging of amniotic band sequence: utility and role of fetal MRI as an adjunct to prenatal US

    Energy Technology Data Exchange (ETDEWEB)

    Neuman, Jeremy [Cincinnati Children' s Hospital Medical Center, Department of Radiology, Cincinnati, OH (United States); Staten Island University Hospital, Department of Radiology, Staten Island, NY (United States); Calvo-Garcia, Maria A.; Kline-Fath, Beth M.; Bitters, Constance; Merrow, Arnold C.; Guimaraes, Carolina V.A. [Cincinnati Children' s Hospital Medical Center, Department of Radiology, Cincinnati, OH (United States); Lim, Foong-Yen [Cincinnati Children' s Hospital Medical Center, Department of Fetal Surgery, Cincinnati, OH (United States)

    2012-05-15

    Amniotic band sequence and its US manifestations have been well-described. There is little information, however, regarding the accuracy and utility of fetal MRI. To describe the MRI findings in amniotic band sequence and to compare the diagnostic accuracy of MRI and US. Prenatal MRI and US studies were retrospectively reviewed in 14 consecutive pregnancies with confirmed amniotic band sequence. Both studies were evaluated for amniotic band visualization, body part affected, type of deformity, umbilical cord involvement and vascular abnormality. Amniotic bands were confidently identified with MRI in 8 fetuses (57%), suggested with MRI in 3 fetuses (21%) and confidently seen by US in 13 fetuses (93%). Neither modality detected surgically proven bands on one fetus. Both techniques were equally able to define the body part affected and the type of deformity. At least one limb abnormality was visualized in all cases and truncal involvement was present in two cases. Cord involvement was identified in seven cases, with one case detected only by MRI. Fetal MRI is able to visualize amniotic bands and their secondary manifestations and could be complementary to prenatal US when fetal surgery is contemplated. (orig.)

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

    NARCIS (Netherlands)

    van Nierop, Bastiaan J.; Bax, Noortje A. M.; Nelissen, Jules L.; Arslan, Fatih; Motaal, Abdallah G.; de Graaf, Larry; Zwanenburg, Jaco J. M.; Luijten, Peter R.; Nicolay, Klaas; Strijkers, Gustav J.

    2015-01-01

    Background 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

  6. An Matching Method for Vehicle-borne Panoramic Image Sequence Based on Adaptive Structure from Motion Feature

    Directory of Open Access Journals (Sweden)

    ZHANG Zhengpeng

    2015-10-01

    Full Text Available Panoramic image matching method with the constraint condition of local structure from motion similarity feature is an important method, the process requires multivariable kernel density estimations for the structure from motion feature used nonparametric mean shift. Proper selection of the kernel bandwidth is a critical step for convergence speed and accuracy of matching method. Variable bandwidth with adaptive structure from motion feature for panoramic image matching method has been proposed in this work. First the bandwidth matrix is defined using the locally adaptive spatial structure of the sampling point in spatial domain and optical flow domain. The relaxation diffusion process of structure from motion similarity feature is described by distance weighting method of local optical flow feature vector. Then the expression form of adaptive multivariate kernel density function is given out, and discusses the solution of the mean shift vector, termination conditions, and the seed point selection method. The final fusions of multi-scale SIFT the features and structure features to establish a unified panoramic image matching framework. The sphere panoramic images from vehicle-borne mobile measurement system are chosen such that a comparison analysis between fixed bandwidth and adaptive bandwidth is carried out in detail. The results show that adaptive bandwidth is good for case with the inlier ratio changes and the object space scale changes. The proposed method can realize the adaptive similarity measure of structure from motion feature, improves the correct matching points and matching rate, experimental results have shown our method to be robust.

  7. Body image discrepancy and subjective norm as mediators and moderators of the relationship between body mass index and quality of life

    Directory of Open Access Journals (Sweden)

    Pétré B

    2016-11-01

    Full Text Available Benoit Pétré,1 André J Scheen,2 Olivier Ziegler,3 Anne-Françoise Donneau,1 Nadia Dardenne,1 Eddy Husson,1 Adelin Albert,1 Michèle Guillaume1 1Department of Public Health, University of Liège, Liège, Belgium; 2Division of Diabetes, Nutrition and Metabolic Disorders, Department of Medicine, CHU Sart Tilman, University of Liège, Liège, Belgium; 3Department of Diabetes, Metabolic Diseases and Nutrition, Nancy University Hospital, Nancy, France Background and objective: Despite the strength and consistency of the relationship between body mass index (BMI and quality of life (QoL, a reduction in BMI does not necessarily lead to an improvement in QoL. Between-subject variability indicates the presence of mediators and moderators in the BMI–QoL association. This study aimed to examine the roles of body image discrepancy (BID and subjective norm (SN as potential mediators and moderators. Subjects and methods: In 2012, 3,016 volunteers (aged ≥18 years participated in a community-based survey conducted in the French-speaking region of Belgium. Participation was enhanced using a large multimedia campaign (which was supported by a large network of recruiters that employed the nonstigmatizing slogan, “Whatever your weight, your opinion will count”. Participants were invited to complete a web-based questionnaire on their weight-related experiences. Self-reported measures were used to calculate each participant’s BMI, BID, SN, and QoL (a French obesity-specific QoL questionnaire was used to calculate the participants’ physical dimension of QoL scores [PHY-QoL], psychosocial dimension of QoL scores [PSY/SOC-QoL], and their total scores. The covariates included gender, age, subjective economic status, level of education, household size, and perceived health. The mediation/moderation tests were based on Hayes’ method. Results: Tests showed that the relationships between BMI and PHY-QoL, PSY/SOC-QoL, and TOT-QoL were partially mediated by BID

  8. A pilot study on the application of FFE and SSh-TSE sequences in ocular MRI.

    Science.gov (United States)

    Ma, Xiaofen; Tian, Junzhang; Jiang, Guihua; Liang, Lianbao; Zeng, Shaoqing; Li, Wuming

    2011-09-01

    To preliminarily investigate the application value of rapid sequences FFE and SSh-TSE in ocular magnetic resonance imaging (MRI). Ocular MRI was performed in 18 subjects without ocular conditions,and demonstration of 15 delicate anatomic structures on two sequences in each subject was rated by three proficient physicians. FFE sequence was comparatively advantageous in demonstrating delicate structures on ocular wall and ocular adnexa (PSSh-TSE; while SSh-TSE sequence better revealed the delicate anatomy within anterior chamber (PSSh-TSE sequences are able to effectively eliminate the impact from motion artifact and thus result in desirable images with high spatial resolution. The application of high-resolution MR microscopic imaging technique has improved the ability to demonstrate delicate ocular structures.

  9. Body image discrepancy and subjective norm as mediators and moderators of the relationship between body mass index and quality of life.

    Science.gov (United States)

    Pétré, Benoit; Scheen, André J; Ziegler, Olivier; Donneau, Anne-Françoise; Dardenne, Nadia; Husson, Eddy; Albert, Adelin; Guillaume, Michèle

    2016-01-01

    Despite the strength and consistency of the relationship between body mass index (BMI) and quality of life (QoL), a reduction in BMI does not necessarily lead to an improvement in QoL. Between-subject variability indicates the presence of mediators and moderators in the BMI-QoL association. This study aimed to examine the roles of body image discrepancy (BID) and subjective norm (SN) as potential mediators and moderators. In 2012, 3,016 volunteers (aged ≥18 years) participated in a community-based survey conducted in the French-speaking region of Belgium. Participation was enhanced using a large multimedia campaign (which was supported by a large network of recruiters) that employed the nonstigmatizing slogan, "Whatever your weight, your opinion will count". Participants were invited to complete a web-based questionnaire on their weight-related experiences. Self-reported measures were used to calculate each participant's BMI, BID, SN, and QoL (a French obesity-specific QoL questionnaire was used to calculate the participants' physical dimension of QoL scores [PHY-QoL], psychosocial dimension of QoL scores [PSY/SOC-QoL], and their total scores). The covariates included gender, age, subjective economic status, level of education, household size, and perceived health. The mediation/moderation tests were based on Hayes' method. Tests showed that the relationships between BMI and PHY-QoL, PSY/SOC-QoL, and TOT-QoL were partially mediated by BID in both males and females and by SN in females. Moreover, BID was a moderator of the relationship between BMI and PSY/SOC-QoL in males and females. SN was a moderator of the relationship between BMI and PSY/SOC-QoL in males and between BMI and total scores in males (when used without BID in the models). BID and SN should be considered as important factors in obesity management strategies. The study shows that targeting BMI only is not sufficient to improve the QoL of overweight and obese subjects, and that other variables

  10. 3D-imaging of the knee with an optimized 3D-FSE-sequence and a 15-channel knee-coil

    Energy Technology Data Exchange (ETDEWEB)

    Notohamiprodjo, Mike, E-mail: mike.notohamiprodjo@med.uni-muenchen.de [Department of Clinical Radiology, University Hospitals Munich, Marchioninistrasse 15, 81377 Munich (Germany); Department of Radiology, Langone Medical Center, Bernard and Irene Schwartz Center for Biomedical Imaging New York University, 660 First Avenue, 4th Floor, New York, NY 10016 (United States); Horng, Annie; Kuschel, Bernhard [Department of Clinical Radiology, University Hospitals Munich, Marchioninistrasse 15, 81377 Munich (Germany); Paul, Dominik [Siemens Healthcare, Erlangen, Henkestr. 127, 91054 Erlangen (Germany); Li, Guobin [Siemens Mindit Magnetic Resonance Ltd., Shenzhen, Guang Dong (China); Raya, Jose G. [Department of Radiology, Langone Medical Center, Bernard and Irene Schwartz Center for Biomedical Imaging New York University, 660 First Avenue, 4th Floor, New York, NY 10016 (United States); Reiser, Maximilian F. [Department of Clinical Radiology, University Hospitals Munich, Marchioninistrasse 15, 81377 Munich (Germany); Glaser, Christian [Department of Clinical Radiology, University Hospitals Munich, Marchioninistrasse 15, 81377 Munich (Germany); Department of Radiology, Langone Medical Center, Bernard and Irene Schwartz Center for Biomedical Imaging New York University, 660 First Avenue, 4th Floor, New York, NY 10016 (United States)

    2012-11-15

    Objectives: To evaluate the clinical usefulness of an optimized 3D-Fast-Spin-Echo-sequence (3D-SPACE) in combination with a 15-channel knee-coil for 3D-imaging of the knee at 3 T. Methods: 15 volunteers and 50 consecutive patients were examined at 3 T with fat-saturated moderately T2-weighted 3D-SPACE (Voxel-size (VS): 0.6 mm Multiplication-Sign 0.5 mm Multiplication-Sign 0.5 mm/acquisition-time (AT) 10:44 min) using a 15-channel knee-coil. Flip angle optimization and radial k-space reordering were applied. Signal- and contrast-to-noise-ratios (SNR, CNR) were compared to non-optimized 3D-SPACE (8-channel knee-coil) and conventional 2D-FSE (VS: 0.4 mm Multiplication-Sign 0.4 mm Multiplication-Sign 3 mm/total AT: 12 min). Two radiologists independently rated depiction of internal knee structures and assessed detection and depiction of cartilage and meniscus abnormalities compared to conventional 2D-FSE-sequences. Sensitivity and specificity were calculated for a subgroup with arthroscopy as reference standard. Statistical analysis was performed with paired t-tests, confidence intervals and weighted-{kappa}-coefficients. Results: SNR and CNR particularly of fluid/cartilage of optimized 3D-SPACE were significantly higher (p < 0.05) than of the non-optimized 3D-sequence and conventional 2D-sequence. Blurring and image inhomogeneity were reduced in the optimized sequence. The thin slice-thickness was beneficial for depiction of problematical anatomical structures such as meniscal roots. 3D-SPACE showed significantly higher diagnostic confidence (p < 0.05) for diagnosis of cartilage lesions of the femoral trochlea. Overall sensitivity and specificity of 3D-SPACE and 2D-FSE for cartilage lesions was 82.3%/80.2% and 79.4%/84.2% and 100%/86.4% and 92.3%/81.8% for meniscus lesions. Conclusions: Optimized 3D-SPACE provides significantly higher signal and contrast compared to conventional 2D-FSE, particularly for fluid and cartilage, leading to improved diagnostic confidence

  11. Apparatus and method for motion tracking in brain imaging

    DEFF Research Database (Denmark)

    2013-01-01

    Disclosed is apparatus and method for motion tracking of a subject in medical brain imaging. The method comprises providing a light projector and a first camera; projecting a first pattern sequence (S1) onto a surface region of the subject with the light projector, wherein the subject is positioned...... in a scanner borehole of a medical scanner, the first pattern sequence comprising a first primary pattern (P1,1) and/or a first secondary pattern (P1,2); detecting the projected first pattern sequence (S1') with the first camera; determining a second pattern sequence (S2) comprising a second primary pattern (P......2,1) based on the detected first pattern sequence (S1'); projecting the second pattern sequence (S2) onto a surface region of the subject with the light projector; detecting the projected second pattern sequence (S2') with the first camera; and determining motion tracking parameters based...

  12. Deep wide-field imaging down to the oldest main sequence turn-offs in the Sculptor dwarf spheroidal galaxy

    Science.gov (United States)

    de Boer, T. J. L.; Tolstoy, E.; Saha, A.; Olsen, K.; Irwin, M. J.; Battaglia, G.; Hill, V.; Shetrone, M. D.; Fiorentino, G.; Cole, A.

    2011-04-01

    We present wide-field photometry of resolved stars in the nearby Sculptor dwarf spheroidal galaxy using CTIO/MOSAIC, going down to the oldest main sequence turn-off. The accurately flux calibrated wide field colour-magnitude diagrams can be used to constrain the ages of different stellar populations, and also their spatial distribution. The Sculptor dSph contains a predominantly ancient stellar population (>10 Gyr old) which can be easily resolved into individual stars. A galaxy dominated by an old population provides a clear view of ancient processes of galaxy formation unimpeded by overlying younger populations. By using spectroscopic metallicities of RGB stars in combination with our deep main sequence turn-off photometry we can constrain the ages of different stellar populations with particular accuracy. We find that the known metallicity gradient in Sculptor is well matched to an age gradient. This is the first time that this link with age has been directly quantified. This gradient has been previously observed as a variation in horizontal branch properties and is now confirmed to exist for main sequence turn-offs as well. It is likely the Sculptor dSph first formed an extended metal-poor population at the oldest times, and subsequent more metal-rich, younger stars were formed more towards the centre until the gas was depleted or lost roughly 7 Gyr ago. The fact that these clear radial gradients have been preserved up to the present day is consistent with the apparent lack of signs of recent tidal interactions. Appendices are only available in electronic form at http://www.aanda.org

  13. Image processing. Fourier analysis of image sequences in cardiological diagnosis. [GAMMA]. Bildverarbeitung. Fourier-Analyse von Bildsequenzen in der kardiologischen Diagnostik

    Energy Technology Data Exchange (ETDEWEB)

    Kindler, M.; Schmidt, A.; Wolf, E.

    1986-01-01

    The nuclear medical methods developed over the last ten years for cardiological diagnosis are especially suited to evaluating the functional performance of the left ventricle, and myocardial perfusion. Computed tomography and subtraction angiography are two other, non-invasive radiological methods for examining the size and topography of the cavities of the heart, and echocardiography has meanwhile taken the first position in the diagnosis of morphological heart disease. Fourier analysis and the Fourier tansformation technique allow acquisition, recording and evaluation of quantitative data of the radionuclide ventriculography. Due to the weak spatial resolution of the scintigraphic phase analysis, the next logical development was to apply Fourier analysis to the cine-ventriculography, which unfortunately requires considerable computing efforts and time. A solution has now been found that combines the two image processing systems and thus creates the basis for applying the Fourier analysis to all the diagnostic imaging methods, such as echocardiography, radiography, and nuclear medical methods.

  14. Faster pediatric 3-T abdominal magnetic resonance imaging: comparison between conventional and variable refocusing flip-angle single-shot fast spin-echo sequences

    Energy Technology Data Exchange (ETDEWEB)

    Ruangwattanapaisarn, Nichanan [Mahidol University, Department of Diagnostic and Therapeutic Radiology, Ramathibodi Hospital, Bangkok (Thailand); Stanford University, LPCH Department of Radiology, Stanford, CA (United States); Loening, Andreas M.; Saranathan, Manojkumar; Vasanawala, Shreyas S. [Stanford University, LPCH Department of Radiology, Stanford, CA (United States); Litwiller, Daniel V. [GE Healthcare, Rochester, MN (United States)

    2015-06-15

    Single-shot fast spin echo (SSFSE) is particularly appealing in pediatric patients because of its motion robustness. However radiofrequency energy deposition at 3 tesla forces long pauses between slices, leading to longer scans, longer breath-holds and more between-slice motion. We sought to learn whether modulation of the SSFSE refocusing flip-angle train could reduce radiofrequency energy deposition without degrading image quality, thereby reducing inter-slice pauses and overall scan times. We modulated the refocusing flip-angle train for SSFSE to minimize energy deposition while minimizing blurring and motion-related signal loss. In a cohort of 50 consecutive patients (25 boys, mean age 5.5 years, range 1 month to 17 years) referred for abdominal MRI we obtained standard SSFSE and variable refocusing flip-angle (vrfSSFSE) images and recorded sequence scan times. Two readers independently scored the images in blinded, randomized order for noise, tissue contrast, sharpness, artifacts and left lobe hepatic signal uniformity on a four-point scale. The null hypothesis of no difference between SSFSE and vrfSSFSE image-quality was assessed with a Mann-Whitney U test, and the null hypothesis of no scan time difference was assessed with the paired t-test. SSFSE and vrfSSFSE mean acquisition times were 54.3 and 26.2 s, respectively (P-value <0.0001). For each reader, SSFSE and vrfSSFSE noise, tissue contrast, sharpness and artifacts were not significantly different (P-values 0.18-0.86). However, SSFSE had better left lobe hepatic signal uniformity (P < 0.01, both readers). vrfSSFSE is twice as fast as SSFSE, with equivalent image quality with the exception of left hepatic lobe signal heterogeneity. (orig.)

  15. 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.

  16. Semi-Automated Analysis of Diaphragmatic Motion with Dynamic Magnetic Resonance Imaging in Healthy Controls and Non-Ambulant Subjects with Duchenne Muscular Dystrophy

    Directory of Open Access Journals (Sweden)

    Courtney A. Bishop

    2018-01-01

    Full Text Available Subjects with Duchenne Muscular Dystrophy (DMD suffer from progressive muscle damage leading to diaphragmatic weakness that ultimately requires ventilation. Emerging treatments have generated interest in better characterizing the natural history of respiratory impairment in DMD and responses to therapy. Dynamic (cine Magnetic Resonance Imaging (MRI may provide a more sensitive measure of diaphragm function in DMD than the commonly used spirometry. This study presents an analysis pipeline for measuring parameters of diaphragmatic motion from dynamic MRI and its application to investigate MRI measures of respiratory function in both healthy controls and non-ambulant DMD boys. We scanned 13 non-ambulant DMD boys and 10 age-matched healthy male volunteers at baseline, with a subset (n = 10, 10, 8 of the DMD subjects also assessed 3, 6, and 12 months later. Spirometry-derived metrics including forced vital capacity were recorded. The MRI-derived measures included the lung cross-sectional area (CSA, the anterior, central, and posterior lung lengths in the sagittal imaging plane, and the diaphragm length over the time-course of the dynamic MRI. Regression analyses demonstrated strong linear correlations between lung CSA and the length measures over the respiratory cycle, with a reduction of these correlations in DMD, and diaphragmatic motions that contribute less efficiently to changing lung capacity in DMD. MRI measures of pulmonary function were reduced in DMD, controlling for height differences between the groups: at maximal inhalation, the maximum CSA and the total distance of motion of the diaphragm were 45% and 37% smaller. MRI measures of pulmonary function were correlated with spirometry data and showed relationships with disease progression surrogates of age and months non-ambulatory, suggesting that they provide clinically meaningful information. Changes in the MRI measures over 12 months were consistent with weakening of

  17. Ethnic comparison of pharmacokinetics of {sup 18}F-florbetaben, a PET tracer for beta-amyloid imaging, in healthy Caucasian and Japanese subjects

    Energy Technology Data Exchange (ETDEWEB)

    Senda, Michio; Sasaki, Masahiro; Yamane, Tomohiko; Shimizu, Keiji [Institute of Biomedical Research and Innovation, Division of Molecular Imaging, 2-2 Minatojima-Minamimachi, Chuo-ku, Kobe (Japan); Patt, Marianne; Barthel, Henryk; Sattler, Bernhard; Sabri, Osama [University of Leipzig, Department of Nuclear Medicine, Leipzig (Germany); Nagasawa, Toshiki; Aitoku, Yasuko [Bayer Yakuhin Ltd, Osaka (Japan); Schultze-Mosgau, Marcus [Bayer HealthCare AG, Berlin (Germany); Dinkelborg, Ludger [Piramal Imaging GmbH, Berlin (Germany)

    2015-01-15

    {sup 18}F-Florbetaben is a positron emission tomography (PET) tracer indicated for imaging cerebral beta-amyloid deposition in adult patients with cognitive impairment who are being evaluated for Alzheimer's disease and other causes of cognitive decline. The present study examined ethnic comparability of the plasma pharmacokinetics, which is the input to the brain, between Caucasian and Japanese subjects. Two identical phase I trials were performed in 18 German and 18 Japanese healthy volunteers to evaluate the plasma pharmacokinetics of a single dose of 300 MBq {sup 18}F-florbetaben, either of low (≤5 μg, LD) or high (50-55 μg, HD) mass dose. Pharmacokinetic parameters were evaluated based on the total {sup 18}F radioactivity measurements in plasma followed by metabolite analysis using radio-HPLC. The pharmacokinetics of {sup 18}F-florbetaben was characterized by a rapid elimination from plasma. The dose-normalized areas under the curve of {sup 18}F-florbetaben in plasma as an indicator of the input to the brain were comparable between Germans (LD: 0.38 min/l, HD: 0.55 min/l) and Japanese (LD: 0.35 min/l, HD: 0.45 min/l) suggesting ethnic similarity, and the mass dose effect was minimal. A polar metabolite fraction was the main radiolabelled degradation product in plasma and was also similar between the doses and the ethnic groups. Absence of a difference in the pharmacokinetics of {sup 18}F-florbetaben in Germans and Japanese has warranted further global development of the PET imaging agent. (orig.)

  18. A comprehensive visual rating scale of brain magnetic resonance imaging: application in elderly subjects with Alzheimer's disease, mild cognitive impairment, and normal cognition.

    Science.gov (United States)

    Jang, Jae-Won; Park, So Young; Park, Young Ho; Baek, Min Jae; Lim, Jae-Sung; Youn, Young Chul; Kim, SangYun

    2015-01-01

    Brain magnetic resonance imaging (MRI) shows cerebral structural changes. However, a unified comprehensive visual rating scale (CVRS) has seldom been studied. Thus, we combined brain atrophy and small vessel disease scales and used an MRI template as a CVRS. The aims of this study were to design a simple and reliable CVRS, validate it by investigating cerebral structural changes in clinical groups, and made comparison to the volumetric measurements. Elderly subjects (n = 260) with normal cognition (NC, n = 65), mild cognitive impairment (MCI, n = 101), or Alzheimer's disease (AD, n = 94) were evaluated with brain MRI according to the CVRS of brain atrophy and small vessel disease. Validation of the CVRS with structural changes, neuropsychological tests, and volumetric analyses was performed. The CVRS revealed a high intra-rater and inter-rater agreement and it reflected the structural changes of subjects with NC, MCI, and AD better than volumetric measures (CVRS-coronal: F = 13.5, p < 0.001; CVRS-axial: F = 19.9, p < 0.001). The area under the receiver operation curve (aROC) of the CVRS showed higher accuracy than volumetric analyses. (NC versus MCI aROC: CVRS-coronal, 0.777; CVRS-axial, 0.773; MCI versus AD aROC: CVRS-coronal, 0.680; CVRS-axial, 0.681). The CVRS can be used clinically to conveniently measure structural changes of brain. It reflected cerebral structural changes of clinical groups and correlated with the age better than volumetric measures.

  19. The diagnostic efficacy of quantitative liver MR imaging with diffusion-weighted, SWI, and hepato-specific contrast-enhanced sequences in staging liver fibrosis - a multiparametric approach

    Energy Technology Data Exchange (ETDEWEB)

    Feier, Diana [Medical University of Vienna, General Hospital of Vienna (AKH), Department of Biomedical Imaging and Image-guided Therapy, Vienna (Austria); Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca, Emergency County Hospital, Department of Radiology, Cluj-Napoca (Romania); Balassy, Csilla; Bastati, Nina; Fragner, Romana; Ba-Ssalamah, Ahmed [Medical University of Vienna, General Hospital of Vienna (AKH), Department of Biomedical Imaging and Image-guided Therapy, Vienna (Austria); Wrba, Friedrich [Medical University of Vienna, General Hospital of Vienna (AKH), Department of Pathology, Vienna (Austria)

    2016-02-15

    To assess the diagnostic efficacy of multiparametric MRI using quantitative measurements of the apparent diffusion coefficient (ADC) of the liver parenchyma on diffusion-weighted imaging (DWI), signal intensity (SI) on susceptibility-weighted imaging (SWI), and gadoxetic acid-enhanced T1-weighted imaging during the hepatobiliary phase for the staging of liver fibrosis. Seventy-seven patients underwent a 3T MRI examination, including DWI/SWI sequences and gadoxetic acid-enhanced T1-weighted MRI. Liver fibrosis according to liver biopsy was staged using the Metavir fibrosis score: F0 (n = 21, 27.3 %); F1 (n = 7, 9.1 %); F2 (n = 8, 10.4 %); F3 (n = 12, 15.6 %); and F4 (n = 29, 37.7 %). SI of the liver was defined using region-of-interest measurements to calculate the ADC values, the relative enhancement (RE) in the hepatobiliary phase, and the liver-to-muscle ratio (LMR) measurements for SWI. The values of RE, LMR, and ADC measurements were statistically significantly different among the five fibrosis stages (p < 0.004). Combining the three parameters in a multiparametric approach, the AUC for detecting F1 stage or greater (≥ F1) was 94 %, for F2 or greater (≥F2) was 95 %, for F3 or greater (≥F3) was 90 %, and for stage F4 was 93 %. Multiparametric MRI is an efficient non-invasive diagnostic tool for the staging of liver fibrosis. (orig.)

  20. Comparisons of the pharmacokinetics and tolerability of fixed-dose combinations of amlodipine besylate/losartan and amlodipine camsylate/losartan in healthy subjects: a randomized, open-label, single-dose, two-period, two-sequence crossover study.

    Science.gov (United States)

    Choi, YoonJung; Lee, SeungHwan; Cho, Sang-Min; Kang, Won-Ho; Nam, Kyu-Yeol; Jang, In-Jin; Yu, Kyung-Sang

    2016-01-01

    A fixed-dose combination (FDC) of amlodipine and losartan has been used to reduce blood pressure in patients whose hypertension is not sufficiently controlled with either drug alone. The aim of this study was to evaluate the pharmacokinetic (PK) characteristics and tolerability of an FDC of 6.94 mg amlodipine besylate (5 mg as amlodipine)/50 mg losartan potassium compared to an FDC of 5 mg amlodipine camsylate/50 mg losartan potassium in healthy subjects. A randomized, open-label, single-dose, two-period, two-sequence crossover study was conducted on 46 healthy male subjects. Blood concentrations were measured by liquid chromatography-tandem mass spectrometry. Blood samples were collected up to 144 hours post dose for each period. PK parameters were calculated in each treatment group using a noncompartmental method. The 90% confidence intervals (CIs) of the geometric mean ratios of the two treatments for the maximum plasma concentration (Cmax) and the area under the concentration curve from time zero to the last quantifiable time point (AUC0-t) were estimated. Tolerability assessments were performed for all subjects who received the drug at least once. The PK profiles of the two treatments were similar. For amlodipine, the geometric mean ratios (90% CIs) of amlodipine besylate to amlodipine camsylate for the Cmax and AUC0-t were 0.98 (0.94-1.01) and 0.97 (0.93-1.01), respectively. The corresponding values for losartan were 0.91 (0.81-1.02) and 1.05 (0.98-1.12), respectively. The incidence of adverse events was not significantly different between the two treatments, and both were well tolerated. An FDC of 6.94 mg amlodipine besylate (5 mg as amlodipine)/50 mg losartan potassium produced similar results to an FDC of 5 mg amlodipine camsylate/50 mg losartan potassium treatment with respect to the PK parameters of amlodipine and losartan based on Cmax and AUC0-t values. The amlodipine besylate/losartan potassium combination was well tolerated by healthy male subjects.

  1. Reliability of zygapophysial joint space measurements made from magnetic resonance imaging scans of acute low back pain subjects: comparison of 2 statistical methods.

    Science.gov (United States)

    Cramer, Gregory D; Cantu, Joe A; Pocius, Judith D; Cambron, Jerrilyn A; McKinnis, Ray A

    2010-01-01

    This purpose of this study was to assess the reliability of measurements made of the zygapophysial (Z) joint space from the magnetic resonance imaging scans of subjects with acute low back pain using new equipment and 2 different methods of statistical analysis. If found to be reliable, the methods of Z joint measurement can be applied to scans taken before and after spinal manipulation in a larger study of acute low back pain subjects. Three observers measured the central anterior-to-posterior distance of the left and right L4/L5 and L5/S1 Z joint space from 5 subject scans (20 digitizer measurements, rounded to 0.1 mm) on 2 separate occasions separated by 4 weeks. Observers were blinded to each other and their previous work. Intra- and interobserver reliability was calculated by means of intraclass correlation coefficients and also by mean differences using the methods of Bland and Altman (1986). A mean difference of less than +/-0.4 mm was considered clinically acceptable. Intraclass correlation coefficients showed intraobserver reliabilities of 0.95 (95% confidence interval, 0.87-0.98), 0.83 (0.62-0.92), and 0.92 (0.83-0.96) for each of the 3 observers and interobserver reliabilities of 0.90 (0.82-0.95), 0.79 (0.61-0.90), and 0.84 (0.75-0.90) for the first and second measurements and overall reliability, respectively. The mean difference between the first and second measurements was -0.04 mm (+/-1.96 SD = -0.37 to 0.29), 0.23 (-0.48 to 0.94), 0.25 (-0.24 to 0.75), and 0.15 (-0.44 to 0.74) for each of the 3 observers and the overall agreement, respectively. Both statistical methods were found to be useful and complementary and showed the measurements to be highly reliable. Copyright 2010 National University of Health Sciences. Published by Mosby, Inc. All rights reserved.

  2. Positron emission tomography/computerised tomography imaging in detecting and managing recurrent cervical cancer: systematic review of evidence, elicitation of subjective probabilities and economic modelling.

    Science.gov (United States)

    Meads, C; Auguste, P; Davenport, C; Małysiak, S; Sundar, S; Kowalska, M; Zapalska, A; Guest, P; Thangaratinam, S; Martin-Hirsch, P; Borowiack, E; Barton, P; Roberts, T; Khan, K

    2013-03-01

    Cancer of the uterine cervix is a common cause of mortality in women. After initial treatment women may be symptom free, but the cancer may recur within a few years. It is uncertain whether it is more clinically effective to survey asymptomatic women for signs of recurrence or to await symptoms or signs before using imaging. This project compared the diagnostic accuracy of imaging using positron emission tomography/computerised tomography (PET-CT) with that of imaging using CT or magnetic resonance imaging (MRI) alone and evaluated the cost-effectiveness of adding PET-CT as an adjunct to standard practice. Standard systematic review methods were used to obtain and evaluate relevant test accuracy and effectiveness studies. Databases searched included MEDLINE, EMBASE, Science Citation Index and The Cochrane Library. All databases were searched from inception t