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Sample records for resolution speckle tracking

  1. Speckle Tracking Imaging in Normal Stress Echocardiography.

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    Leitman, Marina; Tyomkin, Vladimir; Peleg, Eli; Zyssman, Izhak; Rosenblatt, Simcha; Sucher, Edgar; Gercenshtein, Vered; Vered, Zvi

    2017-04-01

    Exercise stress echocardiography is a widely used modality for the diagnosis and follow-up of patients with coronary artery disease. During the last decade, speckle tracking imaging has been used increasingly for accurate evaluation of cardiac function. This work aimed to assess speckle-tracking imaging parameters during nonischemic exercise stress echocardiography. During 2011 to 2014 we studied 46 patients without history of coronary artery disease, who completed exercise stress echocardiography protocol, had normal left ventricular function, a nonischemic response, and satisfactory image quality. These exams were analyzed with speckle-tracking imaging software at rest and at peak exercise. Peak strain and time-to-peak strain were measured at rest and after exercise. Clinical follow-up included a telephone contact 1 to 3 years after stress echo exam, confirming freedom from coronary events during this time. Global and regional peak strain increased following exercise. Time-to-peak global and regional strain and time-to-peak strain adjusted to the heart rate were significantly shorter in all segments after exercise. Rest-to-stress ratio of time-to-peak strain adjusted to the heart rate was 2.0 to 2.8. Global and regional peak strain rise during normal exercise echocardiography. Peak global and regional strain occur before or shortly after aortic valve closure at rest and after exercise, and the delay is more apparent at the basal segments. Time-to-peak strain normally shortens significantly during exercise; after adjustment to heart rate it shortens by a ratio of 2.0 to 2.8. These data may be useful for interpretation of future exercise stress speckle-tracking echocardiography studies. © 2016 by the American Institute of Ultrasound in Medicine.

  2. Speckle Tracking and Transthyretin Amyloid Cardiomyopathy

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    Alexandre Marins Rocha

    Full Text Available Abstract Background: Amyloidosis is a disease caused by deposits of insoluble fibrils in extracellular spaces. The most common type of familial amyloidosis is mediated by mutation of transthyretin, especially Val30Met. Symptoms and ejection fraction decrease may occur in cardiac amyloidosis only in case of poor prognosis. Myocardial strain detected by two-dimensional speckle tracking echocardiography can indicate changes in myocardial function at early stages of the disease. Objective: To determine the accuracy of left ventricular longitudinal strain by two-dimensional speckle tracking echocardiography in patients with familial amyloidosis caused by Val30Met transthyretin mutation. Methods: Eighteen consecutive patients, carriers of transthyretin mutation, were evaluated by two-dimensional speckle tracking echocardiography, by which myocardial strain curves were obtained, following the American Society of Echocardiography recommendations. Results: Patients were divided into three groups: 1- Val30Met with cardiac amyloidosis; 2-Val30Met with extracardiac amyloidosis; 3 - Val30Met without evidence of disease. As the three groups were compared by the Mann-Whitney test, we found a statistically significant difference between groups 1 and 2 in the mean longitudinal tension (p=0.01, mean basal longitudinal strain (p=0.014; in mean longitudinal tension and mean longitudinal strain between groups 1 and 3 (p=0.005; and in the ratio of longitudinal strain of apical septum segment to longitudinal strain of basal septum (p=0.041 between groups 2 and 3. Conclusion: Left ventricular longitudinal strain detected by two-dimensional speckle tracking echocardiography is able to diagnose left ventricular dysfunction in early stages of familial amyloidosis caused by transthyretin Val30Met mutation.

  3. MODERN POSSIBILITIES OF SPECKLE TRACKING ECHOCARDIOGRAPHY IN CLINICAL PRACTICE

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    V. S. Nikiforov

    2017-01-01

    Full Text Available Speckle-tracking echocardiography is promising modern technique for evaluation of structural and functional changes in the myocardium. It evaluates the indicator of global longitudinal myocardial deformation, which is more sensitive than ejection fraction to early changes of left ventricular contractility. The diagnostic capabilities of speckle tracking echocardiography are reflected in clinical recommendations and consensus statements of European Society of Cardiology (ESC, European Association of Cardiovascular Imaging (EACVI and American Society of Echocardiography (ASE. The aim of this paper is describe basic principles of speckle tracking echocardiography and clinical applications of this new technology. Attention is paid to the use of speckle tracking echocardiography in such heart pathologies as heart failure, coronary heart disease and myocardial infarction, left ventricular hypertrophy in arterial hypertension, hypertrophic cardiomyopathy and amyloidosis of the heart, valvular heart disease, constrictive pericarditis and cancer therapy-induced cardiotoxicity.

  4. Speckle tracking echocardiography in hypertensive males with glucose metabolism disorders

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    M. Yu. Kolesnyk

    2014-12-01

    Full Text Available Aim. Early left ventricle (LV abnormalities are hardly detectable by means of standard echocardiography in patients with hypertension (HTN and glucose metabolism disorders. The objective of this study was to assess changes inLVfunction with speckle tracking echocardiography in hypertensive males with different types of glucose metabolism abnormalities. Methods and results. We recruited 158 hypertensive males with different glycemic status. The multidirectionalLVstrain was assessed by two-dimensional speckle tracking echocardiography. The patients with HTN and type 2 diabetes mellitus demonstrated significant reduction ofLVglobal longitudinal strain and early diastolic strain rate despite preservedLVejection fraction. Conclusion. Speckle tracking echocardiography can identify subclinical myocardial alterations in hypertensive males with glucose metabolism abnormalities.

  5. Frame rate required for speckle tracking echocardiography: A quantitative clinical study with open-source, vendor-independent software.

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    Negoita, Madalina; Zolgharni, Massoud; Dadkho, Elham; Pernigo, Matteo; Mielewczik, Michael; Cole, Graham D; Dhutia, Niti M; Francis, Darrel P

    2016-09-01

    To determine the optimal frame rate at which reliable heart walls velocities can be assessed by speckle tracking. Assessing left ventricular function with speckle tracking is useful in patient diagnosis but requires a temporal resolution that can follow myocardial motion. In this study we investigated the effect of different frame rates on the accuracy of speckle tracking results, highlighting the temporal resolution where reliable results can be obtained. 27 patients were scanned at two different frame rates at their resting heart rate. From all acquired loops, lower temporal resolution image sequences were generated by dropping frames, decreasing the frame rate by up to 10-fold. Tissue velocities were estimated by automated speckle tracking. Above 40 frames/s the peak velocity was reliably measured. When frame rate was lower, the inter-frame interval containing the instant of highest velocity also contained lower velocities, and therefore the average velocity in that interval was an underestimate of the clinically desired instantaneous maximum velocity. The higher the frame rate, the more accurately maximum velocities are identified by speckle tracking, until the frame rate drops below 40 frames/s, beyond which there is little increase in peak velocity. We provide in an online supplement the vendor-independent software we used for automatic speckle-tracked velocity assessment to help others working in this field. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  6. X-ray pulse wavefront metrology using speckle tracking.

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    Berujon, Sebastien; Ziegler, Eric; Cloetens, Peter

    2015-07-01

    An instrument allowing the quantitative analysis of X-ray pulsed wavefronts is presented and its processing method explained. The system relies on the X-ray speckle tracking principle to accurately measure the phase gradient of the X-ray beam from which beam optical aberrations can be deduced. The key component of this instrument, a semi-transparent scintillator emitting visible light while transmitting X-rays, allows simultaneous recording of two speckle images at two different propagation distances from the X-ray source. The speckle tracking procedure for a reference-less metrology mode is described with a detailed account on the advanced processing schemes used. A method to characterize and compensate for the imaging detector distortion, whose principle is also based on speckle, is included. The presented instrument is expected to find interest at synchrotrons and at the new X-ray free-electron laser sources under development worldwide where successful exploitation of beams relies on the availability of an accurate wavefront metrology.

  7. DMD based digital speckle illumination for high resolution imaging

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    Shinde, Anant; Mishra, Ayush; Perinchery, Sandeep M.; Murukeshan, V. M.

    2017-06-01

    Spatially non-uniform illumination patterns have shown significant potential to improve the imaging. Recent developments in the patterned illumination microscopy have demonstrated that the use of an optical speckle as an illumination pattern significantly improves the imaging resolution at the same time reducing the computational overheads. We present a DMD based method for generation of digital speckle pattern. The generated digital speckle and uniform white light illumination are used as two illuminations to acquire images. The image reconstruction algorithm for blind structured illumination microscopy is used to get the high resolution image. Our approach does not require any calibration step or stringent control of the illumination, and dramatically simplifies the experimental set-up.

  8. LHCb VELO Tracking Resolutions

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    Alexander, Michael

    2011-01-01

    The excellent tracking performance of the Vertex Locator (VELO) at LHCb is presented. The resolutions it achieves on single hits, impact parameters, and primary vertex positions are shown, with particular attention paid to measurement of impact parameters.

  9. Deformation-induced speckle-pattern evolution and feasibility of correlational speckle tracking in optical coherence elastography

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    Zaitsev, Vladimir Y.; Matveyev, Alexandr L.; Matveev, Lev A.; Gelikonov, Grigory V.; Gelikonov, Valentin M.; Vitkin, Alex

    2015-07-01

    Feasibility of speckle tracking in optical coherence tomography (OCT) based on digital image correlation (DIC) is discussed in the context of elastography problems. Specifics of applying DIC methods to OCT, compared to processing of photographic images in mechanical engineering applications, are emphasized and main complications are pointed out. Analytical arguments are augmented by accurate numerical simulations of OCT speckle patterns. In contrast to DIC processing for displacement and strain estimation in photographic images, the accuracy of correlational speckle tracking in deformed OCT images is strongly affected by the coherent nature of speckles, for which strain-induced complications of speckle "blinking" and "boiling" are typical. The tracking accuracy is further compromised by the usually more pronounced pixelated structure of OCT scans compared with digital photographic images in classical DIC applications. Processing of complex-valued OCT data (comprising both amplitude and phase) compared to intensity-only scans mitigates these deleterious effects to some degree. Criteria of the attainable speckle tracking accuracy and its dependence on the key OCT system parameters are established.

  10. Comparison of laboratory grating-based and speckle-tracking x-ray phase-contrast imaging

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    Romell, J.; Zhou, T.; Zdora, M.; Sala, S.; Koch, F. J.; Hertz, H. M.; Burvall, A.

    2017-06-01

    Phase-contrast imaging with x-rays is a developing field for imaging weakly absorbing materials. In this work, two phase-contrast imaging methods, grating- and speckle-based imaging, that measure the derivative of the phase shift, have been implemented with a laboratory source and compared experimentally. It was found that for the same dose conditions, the speckle-tracking differential phase-contrast images have considerably higher contrast-to-noise ratio than the grating-based images, but at the cost of lower resolution. Grating-based imaging performs better in terms of resolution, but would require longer exposure times, mainly due to absorption in the grating interferometer.

  11. Speckle tracking echocardiography in mature Irish Wolfhound dogs

    DEFF Research Database (Denmark)

    Westrup, Ulrik; McEvoy, Fintan

    2013-01-01

    Two-dimensional strain measurements obtained by speckle tracking echocardiography (STE) have been reported in both humans and dogs. Incorporation of this technique into canine clinical practice requires the availability of measurements from clinically normal dogs, ideally of the same breed, taken...... under normal clinical conditions.The aims of this prospective study were to assess if it is possible to obtain STE data during a routine echocardiographic examination in Irish Wolfhound dogs and that these data will provide reference values and an estimation of measurement error....

  12. Speeding up 3D speckle tracking using PatchMatch

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    Zontak, Maria; O'Donnell, Matthew

    2016-03-01

    Echocardiography provides valuable information to diagnose heart dysfunction. A typical exam records several minutes of real-time cardiac images. To enable complete analysis of 3D cardiac strains, 4-D (3-D+t) echocardiography is used. This results in a huge dataset and requires effective automated analysis. Ultrasound speckle tracking is an effective method for tissue motion analysis. It involves correlation of a 3D kernel (block) around a voxel with kernels in later frames. The search region is usually confined to a local neighborhood, due to biomechanical and computational constraints. For high strains and moderate frame-rates, however, this search region will remain large, leading to a considerable computational burden. Moreover, speckle decorrelation (due to high strains) leads to errors in tracking. To solve this, spatial motion coherency between adjacent voxels should be imposed, e.g., by averaging their correlation functions.1 This requires storing correlation functions for neighboring voxels, thus increasing memory demands. In this work, we propose an efficient search using PatchMatch, 2 a powerful method to find correspondences between images. Here we adopt PatchMatch for 3D volumes and radio-frequency signals. As opposed to an exact search, PatchMatch performs random sampling of the search region and propagates successive matches among neighboring voxels. We show that: 1) Inherently smooth offset propagation in PatchMatch contributes to spatial motion coherence without any additional processing or memory demand. 2) For typical scenarios, PatchMatch is at least 20 times faster than the exact search, while maintaining comparable tracking accuracy.

  13. 3D Characterization of corneal deformation using ultrasound speckle tracking

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    Keyton Clayson

    2017-11-01

    Full Text Available The three-dimensional (3D mechanical response of the cornea to intraocular pressure (IOP elevation has not been previously reported. In this study, we use an ultrasound speckle tracking technique to measure the 3D displacements and strains within the central 5.5mm of porcine corneas during the whole globe inflation. Inflation tests were performed on dextran-treated corneas (treated with a 10% dextran solution and untreated corneas. The dextran-treated corneas showed an inflation response expected of a thin spherical shell, with through-thickness thinning and in-plane stretch, although the strain magnitudes exhibited a heterogeneous spatial distribution from the central to more peripheral cornea. The untreated eyes demonstrated a response consistent with swelling during experimentation, with through-thickness expansion overriding the inflation response. The average volume ratios obtained in both groups was near 1 confirming general incompressibility, but local regions of volume loss or expansion were observed. These results suggest that biomechanical measurements in 3D provide important new insight to understand the mechanical response of ocular tissues such as the cornea.

  14. Robust motion tracking based on adaptive speckle decorrelation analysis of OCT signal.

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    Wang, Yuewen; Wang, Yahui; Akansu, Ali; Belfield, Kevin D; Hubbi, Basil; Liu, Xuan

    2015-11-01

    Speckle decorrelation analysis of optical coherence tomography (OCT) signal has been used in motion tracking. In our previous study, we demonstrated that cross-correlation coefficient (XCC) between Ascans had an explicit functional dependency on the magnitude of lateral displacement (δx). In this study, we evaluated the sensitivity of speckle motion tracking using the derivative of function XCC(δx) on variable δx. We demonstrated the magnitude of the derivative can be maximized. In other words, the sensitivity of OCT speckle tracking can be optimized by using signals with appropriate amount of decorrelation for XCC calculation. Based on this finding, we developed an adaptive speckle decorrelation analysis strategy to achieve motion tracking with optimized sensitivity. Briefly, we used subsequently acquired Ascans and Ascans obtained with larger time intervals to obtain multiple values of XCC and chose the XCC value that maximized motion tracking sensitivity for displacement calculation. Instantaneous motion speed can be calculated by dividing the obtained displacement with time interval between Ascans involved in XCC calculation. We implemented the above-described algorithm in real-time using graphic processing unit (GPU) and demonstrated its effectiveness in reconstructing distortion-free OCT images using data obtained from a manually scanned OCT probe. The adaptive speckle tracking method was validated in manually scanned OCT imaging, on phantom as well as in vivo skin tissue.

  15. Dictionary learning-based spatiotemporal regularization for 3D dense speckle tracking

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    Lu, Allen; Zontak, Maria; Parajuli, Nripesh; Stendahl, John C.; Boutagy, Nabil; Eberle, Melissa; O'Donnell, Matthew; Sinusas, Albert J.; Duncan, James S.

    2017-03-01

    Speckle tracking is a common method for non-rigid tissue motion analysis in 3D echocardiography, where unique texture patterns are tracked through the cardiac cycle. However, poor tracking often occurs due to inherent ultrasound issues, such as image artifacts and speckle decorrelation; thus regularization is required. Various methods, such as optical flow, elastic registration, and block matching techniques have been proposed to track speckle motion. Such methods typically apply spatial and temporal regularization in a separate manner. In this paper, we propose a joint spatiotemporal regularization method based on an adaptive dictionary representation of the dense 3D+time Lagrangian motion field. Sparse dictionaries have good signal adaptive and noise-reduction properties; however, they are prone to quantization errors. Our method takes advantage of the desirable noise suppression, while avoiding the undesirable quantization error. The idea is to enforce regularization only on the poorly tracked trajectories. Specifically, our method 1.) builds data-driven 4-dimensional dictionary of Lagrangian displacements using sparse learning, 2.) automatically identifies poorly tracked trajectories (outliers) based on sparse reconstruction errors, and 3.) performs sparse reconstruction of the outliers only. Our approach can be applied on dense Lagrangian motion fields calculated by any method. We demonstrate the effectiveness of our approach on a baseline block matching speckle tracking and evaluate performance of the proposed algorithm using tracking and strain accuracy analysis.

  16. LHCb VELO tracking resolutions

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    Alexander, M. T.; LHCb VELO Group

    2013-01-01

    The LHCb detector at the Large Hadron Collider (LHC) at CERN is designed to make precision measurements of mesons and baryons containing b and c quarks. Many analyses performed using data from LHCb examine properties of particles and anti-particles as a function of proper decay time. Precise measurements of production and decay vertices are thus essential. The Vertex Locator (VELO) subdetector of LHCb performs this task. The excellent performance of the VELO with respect to the resolutions it achieves on single hits, impact parameters, and primary vertex positions is presented, with particular attention paid to measurement of impact parameters.

  17. Real-time three-dimensional speckle tracking echocardiography: technical aspects and clinical applications

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    Sorrentino R

    2016-11-01

    Full Text Available Regina Sorrentino, Roberta Esposito, Enrica Pezzullo, Maurizio Galderisi Department of Advanced Biomedical Sciences, Interdepartmental Laboratory of Cardiac Imaging, Federico II University Hospital, Naples, Italy Abstract: Three-dimensional speckle tracking echocardiography (3D STE is a novel technique for the quantification of cardiac deformation based on tracking of ultrasonic speckles in gray scale full-volume 3D images. Developments in ultrasound technologies have made 3D speckle tracking widely available. Two-dimensional echocardiography has intrinsic limitations regarding estimation of left ventricular (LV volumes, ejection fraction, and LV mechanics, due to its inherent foreshortening errors and dependency on geometric models. The development of 3D echocardiography has improved reproducibility and accuracy. Data regarding the feasibility, accuracy, and clinical applications of 3D STE are rapidly assembling. From the tracking results, 3D STE derives several parameters, including longitudinal, circumferential and radial strain, as well as a combined assessment of longitudinal and circumferential strain, termed area strain. 3D STE can also quantify LV rotational movements such as rotation, twist, and torsion. 3D STE provides a better insight on global and regional myocardial deformation. Main applications include detection of subclinical myocardial involvement in heart failure, arterial hypertension, dyssynchrony, and ischemic heart disease. Emerging areas of application include a large spectrum of heart-involving systemic conditions, such as prediction of rejection in heart transplant patients, early detection of cardiotoxicity in patients receiving chemotherapy for cancer, and deeper physiological understanding of LV contraction mechanics in different types of athletes. Aim of this review is to discuss background, technical acquisition and processing aspects as well as recognized and developing clinical applications of this emerging

  18. Reference values of right atrial longitudinal strain imaging by two-dimensional speckle tracking.

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    Padeletti, Margherita; Cameli, Matteo; Lisi, Matteo; Malandrino, Angela; Zacà, Valerio; Mondillo, Sergio

    2012-02-01

    The role of speckle tracking in the assessment of right atrial (RA) deformation dynamics has not been established yet. The reference ranges of RA longitudinal strain indices were measured by speckle tracking in a population of normal subjects. In 84 healthy individuals, peak atrial longitudinal strain (PALS), peak atrial contraction strain (PACS), and time to peak longitudinal strain (TPLS) were measured using a six-segment model for the RA. Strain rate (SR) was also measured starting from the QRS-wave onset, peak positive (x-wave), first peak negative (y-wave), and second negative peak (z-wave). The time from the QRS onset was measured to each wave peak. Adequate tracking quality was achieved in 64% of segments analyzed. Inter- and intraobserver variability coefficients of measurements ranged between 6% and 11%. Global PALS was 49 ± 13%, global TPLS was 363 ± 59 msec, x-wave was 2.12 ± 0.58 sec(-1) , y-wave was -1.91 ± 0.63 sec(-1) , and z-wave was -2.18 ± 0.78 sec(-1) . Speckle tracking is a feasible technique for the assessment of longitudinal myocardial RA deformation. Reference ranges of strain indices were reported. © 2011, Wiley Periodicals, Inc.

  19. Radial and longitudinal strain and strain rate assessed by speckle-tracking echocardiography in dogs with myxomatous mitral valve disease

    DEFF Research Database (Denmark)

    Zois, Nora Elisabeth; Tidholm, A.; Nägga, K.M.

    2012-01-01

    Assessment of left ventricular (LV) function using conventional echocardiographic methods is difficult in mitral regurgitation (MR) owing to altered hemodynamic loading conditions. Newer methods such as speckle-tracking echocardiography (STE) provide assessment of LV strain (St) and strain rates ...

  20. Usefulness of speckle tracking echocardiography in hypertensive crisis and the effect of medical treatment.

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    Alam, Mahboob; Zhang, Lily; Stampehl, Mark; Lakkis, Nasser; Dokainish, Hisham

    2013-07-15

    The acute impact of hypertensive crisis, and changes after treatment, on left ventricular (LV) systolic and diastolic function using comprehensive echocardiography, including speckle tracking, has not been well characterized. Thirty consecutive patients admitted to the hospital from the emergency room with hypertensive crisis underwent Doppler echocardiography at baseline and after blood pressure optimization. The mean age of the patients was 54 ± 13 years, with 19 men (63%). The most common presenting symptoms included dyspnea (70%), chest pain (43%), and altered mental status (13%). Mean systolic and diastolic blood pressures at presentation were 198 ± 12 and 122 ± 12 mm Hg, decreasing to 143 ± 15 and 77 ± 12 mm Hg (p hypertensive crisis and significantly improved after medical treatment. LV diastolic function, assessed using conventional and speckle-tracking parameters, was also depressed and significantly improved after treatment. Copyright © 2013 Elsevier Inc. All rights reserved.

  1. Left ventricular mechanics in isolated mild mitral stenosis: a three dimensional speckle tracking study.

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    Poyraz, Esra; Öz, Tuğba Kemaloğlu; Zeren, Gönül; Güvenç, Tolga Sinan; Dönmez, Cevdet; Can, Fatma; Güvenç, Rengin Çetin; Dayı, Şennur Ünal

    2017-09-01

    In a fraction of patients with mild mitral stenosis, left ventricular systolic function deteriorates despite the lack of hemodynamic load imposed by the dysfunctioning valve. Neither the predisposing factors nor the earlier changes in left ventricular contractility were understood adequately. In the present study we aimed to evaluate left ventricular mechanics using three-dimensional (3D) speckle tracking echocardiography. A total of 31 patients with mild rheumatic mitral stenosis and 27 healthy controls were enrolled to the study. All subjects included to the study underwent echocardiographic examination to collect data for two- and three-dimensional speckle-tracking based stain, twist angle and torsion measurements. Data was analyzed offline with a echocardiographic data analysis software. Patients with rheumatic mild MS had lower global longitudinal (p risk for developing overt systolic dysfunction.

  2. Left Ventricular Longitudinal Function Assessed by Speckle Tracking Ultrasound from a Single Apical Imaging Plane

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    Thomas Bagger

    2012-01-01

    Full Text Available Background. Transthoracic ultrasonography of the heart is valuable in monitoring and treatment of critically ill patients. Speckle tracking ultrasound (STU has proven valid in estimating left ventricular systolic deformation. The aims of the study were to compare conventional and automated STU and to determine whether left ventricular systolic deformation could be estimated from one single imaging plane. Methods. 2D-echocardiography cine-loops were obtained from 20 patients for off-line speckle tracking analysis, consisting of manually tracing of the endocardial border (conventional method or automatically drawn boundaries (automated method. Results. We found a bias of 0,6 (95% CI −2.2−3.3 for global peak systolic strain comparing the automated and the conventional method. Comparing global peak systolic strain of apical 4-chamber cine-loops with averaged Global Peak Strain obtained from apical 4, 2 and long axis cine-loops, showed a bias of 0.1 (95% CI −3.9−4.0. The agreement between subcostal 4-chamber and apical 4-chamber global peak systolic strain was 4.4 (95% CI −3.7−12.5. Conclusion. We found good agreement between the conventional and the automated method. STU applied to single apical 4-chamber cine-loops is in excellent agreement with overall averaged global peak systolic strain, while subcostal 4-chamber cine-loops proved less compliant with speckle tracking ultrasound.

  3. Acute myocarditis with normal wall motion detected with 2D speckle tracking echocardiography

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    Thomas Sturmberger

    2016-05-01

    Full Text Available We present the case of a 26-year-old male with acute tonsillitis who was referred for coronary angiography because of chest pain, elevated cardiac biomarkers, and biphasic T waves. The patient had no cardiovascular risk factors. Echocardiography showed no wall motion abnormalities and no pericardial effusion. 2D speckle tracking revealed distinct decreased regional peak longitudinal systolic strain in the lateral and posterior walls. Ischemic disease was extremely unlikely in view of his young age, negative family history regarding coronary artery disease, and lack of regional wall motion abnormalities on the conventional 2D echocardiogram. Coronary angiography was deferred as myocarditis was suspected. To confirm the diagnosis, cardiac magnetic resonance tomography (MRT was performed, showing subepicardial delayed hyperenhancement in the lateral and posterior walls correlating closely with the strain pattern obtained by 2D speckle tracking echocardiography. With a working diagnosis of acute myocarditis associated with acute tonsillitis, we prescribed antibiotics and nonsteroidal anti-inflammatory drugs. The patient’s clinical signs resolved along with normalization of serum creatine kinase (CK levels, and the patient was discharged on the third day after admission. Learning points: • Acute myocarditis can mimic acute coronary syndromes. • Conventional 2D echocardiography lacks specific features for detection of subtle regional wall motion abnormalities. • 2D speckle tracking expands the scope of echocardiography in identifying myocardial dysfunction derived from edema in acute myocarditis.

  4. Speckle-tracking X-ray phase-contrast imaging for samples with obvious edge-enhancement effect

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    Wang, Feixiang; Wang, Yudan; Wei, Gongxiang; Du, Guohao; Xue, Yanling; Hu, Tao; Li, Ke; Deng, Biao; Xie, Honglan; Xiao, Tiqiao

    2017-10-01

    Compared to the grating or crystal-based X-ray phase contrast imaging, the speckle-tracking method has the advantages of a simple setup and two-dimensional imaging. However, the edge-enhancement effect prevents the application of the speckle-tracking imaging to a large variety of samples. In this letter, an image reconstruction method is proposed to solve this problem. The experimental results from phantom, a biomedical sample, and a sample with a speckle-resembling structure demonstrated that the proposed method is efficacious in eliminating the effect of edge enhancement. The proposed method may greatly expand the application of the speckle-tracking method to most biomedical and material samples.

  5. Retooling Laser Speckle Contrast Analysis Algorithm to Enhance Non-Invasive High Resolution Laser Speckle Functional Imaging of Cutaneous Microcirculation

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    Gnyawali, Surya C.; Blum, Kevin; Pal, Durba; Ghatak, Subhadip; Khanna, Savita; Roy, Sashwati; Sen, Chandan K.

    2017-01-01

    Cutaneous microvasculopathy complicates wound healing. Functional assessment of gated individual dermal microvessels is therefore of outstanding interest. Functional performance of laser speckle contrast imaging (LSCI) systems is compromised by motion artefacts. To address such weakness, post-processing of stacked images is reported. We report the first post-processing of binary raw data from a high-resolution LSCI camera. Sharp images of low-flowing microvessels were enabled by introducing inverse variance in conjunction with speckle contrast in Matlab-based program code. Extended moving window averaging enhanced signal-to-noise ratio. Functional quantitative study of blood flow kinetics was performed on single gated microvessels using a free hand tool. Based on detection of flow in low-flow microvessels, a new sharp contrast image was derived. Thus, this work presents the first distinct image with quantitative microperfusion data from gated human foot microvasculature. This versatile platform is applicable to study a wide range of tissue systems including fine vascular network in murine brain without craniotomy as well as that in the murine dorsal skin. Importantly, the algorithm reported herein is hardware agnostic and is capable of post-processing binary raw data from any camera source to improve the sensitivity of functional flow data above and beyond standard limits of the optical system.

  6. Speckle correlation resolution enhancement of wide-field fluorescence imaging (Conference Presentation)

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    Yilmaz, Hasan

    2016-03-01

    Structured illumination enables high-resolution fluorescence imaging of nanostructures [1]. We demonstrate a new high-resolution fluorescence imaging method that uses a scattering layer with a high-index substrate as a solid immersion lens [2]. Random scattering of coherent light enables a speckle pattern with a very fine structure that illuminates the fluorescent nanospheres on the back surface of the high-index substrate. The speckle pattern is raster-scanned over the fluorescent nanospheres using a speckle correlation effect known as the optical memory effect. A series of standard-resolution fluorescence images per each speckle pattern displacement are recorded by an electron-multiplying CCD camera using a commercial microscope objective. We have developed a new phase-retrieval algorithm to reconstruct a high-resolution, wide-field image from several standard-resolution wide-field images. We have introduced phase information of Fourier components of standard-resolution images as a new constraint in our algorithm which discards ambiguities therefore ensures convergence to a unique solution. We demonstrate two-dimensional fluorescence images of a collection of nanospheres with a deconvolved Abbe resolution of 116 nm and a field of view of 10 µm × 10 µm. Our method is robust against optical aberrations and stage drifts, therefore excellent for imaging nanostructures under ambient conditions. [1] M. G. L. Gustafsson, J. Microsc. 198, 82-87 (2000). [2] H. Yilmaz, E. G. van Putten, J. Bertolotti, A. Lagendijk, W. L. Vos, and A. P. Mosk, Optica 2, 424-429 (2015).

  7. Estudo da Mecânica Cardíaca pelo Speckle Tracking

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    Maria Cristina Donadio Abduch

    2014-04-01

    Full Text Available Speckles, ou marcadores naturais do miocárdio, originam se da interferência construtiva e destrutiva do feixe de ultrassom que incide sobre os tecidos, podem fornecer um diagnóstico precoce das alterações miocárdicas e atuar na predição de certos eventos cardíacos. Devido à sua relativa estabilidade temporal, os speckles podem ser rastreados durante o ciclo cardíaco por software dedicados, promovendo a análise da função sistólica e diastólica. São identificados tanto pela escala de cinza da ecocardiografia 2D convencional quanto pela ecocardiografia 3D, sendo independentes do ângulo de incidência do ultrassom, permitindo assim a avaliação da mecânica cardíaca nos três planos espaciais: longitudinal, circunferencial e radial. O objetivo do presente artigo é discutir o papel e o significado da deformação cardíaca obtida por meio do speckle tracking durante a avaliação da fisiologia cardíaca, e discutir as aplicações clínicas desta tecnologia ecocardiográfica inovadora.

  8. Clinical utility of speckle-tracking echocardiography in cardiac resynchronisation therapy

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    Sitara G Khan

    2016-05-01

    Full Text Available Cardiac resynchronisation therapy (CRT can profoundly improve outcome in selected patients with heart failure; however, response is difficult to predict and can be absent in up to one in three patients. There has been a substantial amount of interest in the echocardiographic assessment of left ventricular dyssynchrony, with the ultimate aim of reliably identifying patients who will respond to CRT. The measurement of myocardial deformation (strain has conventionally been assessed using tissue Doppler imaging (TDI, which is limited by its angle dependence and ability to measure in a single plane. Two-dimensional speckle-tracking echocardiography is a technique that provides measurements of strain in three planes, by tracking patterns of ultrasound interference (‘speckles’ in the myocardial wall throughout the cardiac cycle. Since its initial use over 15 years ago, it has emerged as a tool that provides more robust, reproducible and sensitive markers of dyssynchrony than TDI. This article reviews the use of two-dimensional and three-dimensional speckle-tracking echocardiography in the assessment of dyssynchrony, including the identification of echocardiographic parameters that may hold predictive potential for the response to CRT. It also reviews the application of these techniques in guiding optimal LV lead placement pre-implant, with promising results in clinical improvement post-CRT.

  9. Left ventricular adaptation after TAVI evaluated by conventional and speckle-tracking echocardiography.

    Science.gov (United States)

    Dimitriadis, Zisis; Scholtz, Smita; Ensminger, Stephan; Wiemer, Marcus; Fischbach, Thomas; Scholtz, Werner; Piper, Cornelia; Börgermann, Jochen; Bitter, Thomas; Horstkotte, Dieter; Faber, Lothar

    2017-02-01

    Our study aimed to evaluate myocardial adaption and outcome after transfemoral aortic valve implantation (TAVI TF) for severe aortic stenosis by LV ejection fraction (LVEF) and speckle tracking analysis. From 168 patients who underwent TAVI TF between 2010 and 2013 in our institution, n=95 with a follow-up period ≥3months were included and grouped (G) according to baseline left ventricular ejection fraction (LVEF; G1: LVEF55%). LV function was evaluated using conventional and speckle-tracking based parameters. Mortality was tracked up to 60months. Aortic valve orifice diameter and mean aortic gradient improved significantly after TAVI. LV dimensions and LVEF remained largely unchanged. Systolic function significantly improved in G1 (LVEF, p8% than with LVEF deterioration >8% (p=0.04). GLS changes had no significant impact on mortality. In patient with aortic stenosis and LVEF impairment at baseline, TAVI results in an improved LVEF, while patients with a high LVEF at baseline experience a normalization of LVEF after TAVI. Independent of the baseline value, a deterioration of LVEF leads to a significant increase in mortality. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  10. Speckle tracking evaluation of right ventricular functions in children with sickle cell disease.

    Science.gov (United States)

    Tolba, Osama Abd Rab Elrasol; El-Shanshory, Mohamed Ramadan; El-Gamasy, Mohamed Abd Elaziz; El-Shehaby, Walid Ahmed

    2017-01-01

    Cardiac dysfunction is a risk factor for death in patients with sickle cell disease (SCD). Aim of the work is to evaluate the right ventricular systolic and diastolic functions by tissue Doppler and speckling tracking imaging in children with SCD. Thirty children with SCD and thirty controls were subjected to clinical, laboratory evaluations, and echocardiographic study using GE Vivid 7 (GE Medical System, Horten, Norway with a 3.5-MHz multifrequency transducer) including; Two-dimensional and tissue Doppler echocardiographic study (lateral tricuspid valve annulus peak E' velocity, lateral tricuspid valve annulus peak A' velocity, E'/A' ratio, isovolumetric relaxation time, lateral tricuspid valve annulus S' and septal S' waves and peak longitudinal systolic strain [PLSS] and time to PLSS) were done in six right ventricular segments. There was a significant decrease in right ventricular systolic and diastolic function in patients group when compared to controls. Children with SCD have impaired right ventricular systolic and diastolic functions when compared to healthy children with early evaluation of the systolic dysfunction by speckle tracking imaging technique.

  11. Changes in three-dimensional speckle-tracking-derived myocardial strain during percutaneous coronary intervention.

    Science.gov (United States)

    Ternacle, Julien; Gallet, Romain; Champagne, Stéphane; Teiger, Emmanuel; Gellen, Barnabas; Dubois Randé, Jean-Luc; Gueret, Pascal; Lim, Pascal

    2013-12-01

    The aim of this study was to evaluate changes in three-dimensional (3D) speckle-tracking-derived myocardial strain during ischemia. Twenty patients referred for percutaneous coronary intervention were studied (mean age, 65 ± 11 years; mean left ventricular ejection fraction, 56 ± 7%). Of the 20 study patients, 12 had severe left anterior descending coronary artery stenosis. A full-volume apical view using multibeat 3D modality and two-dimensional (2D) apical views (four chamber, two chamber, and three chamber) were recorded during coronary occlusion before wall motion abnormalities. After percutaneous coronary intervention, ultrasound contrast agent was selectively delivered through the target lesion to delineate ischemic and peri-ischemic segments (ischemia-adjacent segments). Strain values derived from 2D and 3D speckle-tracking echocardiography were compared in ischemic and nonischemic segments. Despite no changes in wall motion and 2D left ventricular ejection fraction (56 ± 7% vs 56 ± 7%), global longitudinal strain by 2D imaging was impaired during percutaneous coronary intervention (-16 ± 3% vs -14 ± 3%, P = .01). Similar changes were observed for all 3D strain components: -11 ± 16% for longitudinal (-15 ± 4% vs -13 ± 4%, P = .03), -13 ± 25% for circumferential (-15 ± 4% vs -12 ± 4%, P = .02), -12 ± 16% for area (-25 ± 5% vs -22 ± 6%, P = .009), and -12 ± 25% for radial global strain (39 ± 12% vs 33 ± 12%, P = .04). During coronary occlusion, 2D longitudinal peak strain and all 3D peak strain components decreased in ischemic segments, while no changes was observed in nonischemic segments. In peri-ischemic segments, only 3D longitudinal and area strain were impaired during ischemia. Changes in myocardial deformation related to ischemia can be characterized by 3D speckle-tracking echocardiography before the stage of wall motion abnormality. Copyright © 2013 American Society of

  12. Speckle tracking echocardiography in chronic obstructive pulmonary disease and overlapping obstructive sleep apnea

    Directory of Open Access Journals (Sweden)

    Pizarro C

    2016-08-01

    Full Text Available Carmen Pizarro,* Fabian van Essen,* Fabian Linnhoff, Robert Schueler, Christoph Hammerstingl, Georg Nickenig, Dirk Skowasch, Marcel Weber Department of Internal Medicine II, Cardiology, Pneumology and Angiology, University Hospital Bonn, Bonn, Germany *These authors contributed equally to this work Background: COPD and congestive heart failure represent two disease entities of growing global burden that share common etiological features. Therefore, we aimed to identify the degree of left ventricular (LV dysfunction in COPD as a function of COPD severity stages and concurrently placed particular emphasis on the presence of overlapping obstructive sleep apnea (OSA.Methods: A total of 85 COPD outpatients (64.1±10.4 years, 54.1% males and 20 controls, matched for age, sex, and smoking habits, underwent speckle tracking echocardiography for LV longitudinal strain imaging. Complementary 12-lead electrocardiography, laboratory testing, and overnight screening for sleep-disordered breathing using the SOMNOcheck micro® device were performed.Results: Contrary to conventional echocardiographic parameters, speckle tracking echocardiography revealed significant impairment in global LV strain among COPD patients compared to control smokers (-13.3%±5.4% vs -17.1%±1.8%, P=0.04. On a regional level, the apical septal LV strain was reduced in COPD (P=0.003 and associated with the degree of COPD severity (P=0.02. With regard to electrocardiographic findings, COPD patients exhibited a significantly higher mean heart rate than controls (71.4±13.0 beats per minute vs 60.3±7.7 beats per minute, P=0.001 that additionally increased over Global Initiative for Chronic Obstructive Lung Disease stages (P=0.01. Albeit not statistically significant, COPD led to elevated N-terminal pro-brain natriuretic peptide levels (453.2±909.0 pg/mL vs 96.8±70.0 pg/mL, P=0.08. As to somnological testing, the portion of COPD patients exhibiting overlapping OSA accounted for 5.9% and

  13. Hybrid Young interferometer for high resolution measurement of dynamic speckle using high birefringence liquid crystal

    Science.gov (United States)

    Bennis, N.; Holdynski, Z.; Merta, I.; Marc, P.; Kula, P.; Mazur, R.; Piecek, W.; Jaroszewicz, L. R.

    2015-08-01

    It is well known that the Young interference experiment is the fundamental setup to combine two beams and to construct the phase modulated light. Moreover, homodyne phase demodulator is based on signal decoding in back Fourier focal plane using bicell photodetector (B-PD). On the above base, we propose a novel experimental approach to the signals demodulation by using the optical interferometer which operates in homodyne mode, combined with liquid crystal spatial light modulators operating both phase as speckle modulator. Dynamic phase changes between the two beams can be controlled by monopixel liquid crystals cell placed in one branch of the interferometer. A phase modulation effect in a signal arm of interferometer is observed as a dynamic shift of the speckle pattern. Simple arithmetic combination of signals from B-PD placed in speckle pattern plane is only one necessary numerical manipulation to obtain exactly phase difference. Concept of signals demodulation in the Fourier focal plane can be only used for exactly defined geometrical (B-PD as well as Young interferometer) and physical parameters (polarization, wavelength). We optimize the setup geometry to obtain extremely high measurement resolution. In this paper we focus on the principles of operation of each part of the system as well as discussion their requirement in order to increase the signal to noise ratio.

  14. Image-based speckle tracking for tissue motion characterization in a deformable cardiovascular phantom

    Science.gov (United States)

    Chan, R.; Manzke, R.; Dalal, S.; Stanton, D.; Chang, P.; Settlemier, S.; Salgo, I.; Tournoux, F.

    2008-03-01

    We present and validate image-based speckle-tracking calipers for quantification of tissue deformation and rotation in dynamic cardiovascular phantom models. Lagrangian strain was computed from the change in distance between caliper regions-of-interest (ROIs) positioned within the wall of a pulsatile phantom and compared with reference measurements derived from cardiac CT imaging. In a torsion phantom, rotational tissue excursion in a 2D plane was estimated and compared with reference values from CT-scan data. Tissue deformation and rotation measurements correlated well with their respective reference measurements. Our algorithm is capable of estimating strain and rotation from distinct tissue regions without requiring explicit cardiac border detection, a step which can be especially challenging in patients with poor acoustic windows.

  15. Archeological Echocardiography: Digitization and Speckle Tracking Analysis of Archival Echocardiograms in the HyperGEN Study.

    Science.gov (United States)

    Aguilar, Frank G; Selvaraj, Senthil; Martinez, Eva E; Katz, Daniel H; Beussink, Lauren; Kim, Kwang-Youn A; Ping, Jie; Rasmussen-Torvik, Laura; Goyal, Amita; Sha, Jin; Irvin, Marguerite R; Arnett, Donna K; Shah, Sanjiv J

    2016-03-01

    Several large epidemiologic studies and clinical trials have included echocardiography, but images were stored in analog format and these studies predated tissue Doppler imaging (TDI) and speckle tracking echocardiography (STE). We hypothesized that digitization of analog echocardiograms, with subsequent quantification of cardiac mechanics using STE, is feasible, reproducible, accurate, and produces clinically valid results. In the NHLBI HyperGEN study (N = 2234), archived analog echocardiograms were digitized and subsequently analyzed using STE to obtain tissue velocities/strain. Echocardiograms were assigned quality scores and inter-/intra-observer agreement was calculated. Accuracy was evaluated in: (1) a separate second study (N = 50) comparing prospective digital strain versus post hoc analog-to-digital strain, and (2) in a third study (N = 95) comparing prospectively obtained TDI e' velocities with post hoc STE e' velocities. Finally, we replicated previously known associations between tissue velocities/strain, conventional echocardiographic measurements, and clinical data. Of the 2234 HyperGEN echocardiograms, 2150 (96.2%) underwent successful digitization and STE analysis. Inter/intra-observer agreement was high for all STE parameters, especially longitudinal strain (LS). In accuracy studies, LS performed best when comparing post hoc STE to prospective digital STE for strain analysis. STE-derived e' velocities correlated with, but systematically underestimated, TDI e' velocity. Several known associations between clinical variables and cardiac mechanics were replicated in HyperGEN. We also found a novel independent inverse association between fasting glucose and LS (adjusted β = -2.4 [95% CI -3.6, -1.2]% per 1-SD increase in fasting glucose; P digitization and speckle tracking analysis of archival echocardiograms, is feasible and generates indices of cardiac mechanics similar to contemporary studies. © 2015, Wiley Periodicals, Inc.

  16. Left atrial deformation and phasic function determined by 2-dimensional speckle tracking echocardiography in healthy dogs.

    Science.gov (United States)

    Caivano, D; Rishniw, M; Patata, V; Giorgi, M E; Birettoni, F; Porciello, F

    2016-06-01

    Feasibility, intra- and inter-observer variability of measuring left atrial (LA) longitudinal strain and strain rate (SR) variables using speckle tracking echocardiography (STE) have not been reported in the dog. Reference intervals for these variables which can be useful to estimate LA function have been provided. Forty-eight healthy adult dogs. Left atrial longitudinal deformation was evaluated in each dog by STE, and different combinations of STE variables were used to describe the 3 phases (reservoir, conduit and booster pump phase) of the LA function. Left atrial STE was possible in 40/48 dogs (83%). Strain and SR curves in healthy dogs were characterized, and reference intervals for several strain and SR variables are provided. Intra- and inter-observer variability, expressed as percent difference between observations or observers, was 3.58%-10.8% for indices of the LA reservoir function, 10.48%-15.82% for indices of the LA conduit function and 14.1%-34% for indices of the LA contractile function. Strain rate in early diastole and strain rate at atrial contraction variables were correlated significantly with age. No other relationships (body weight, heart rate or LA size) with any STE variables could be identified. Speckle tracking echocardiography provides quantitative measurements of LA longitudinal deformation and can be used to assess LA phasic function in healthy dogs. Further studies of these variables in dogs with cardiac diseases are needed to determine the clinical applicability and utility. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Variability of global left ventricular deformation analysis using vendor dependent and independent two-dimensional speckle-tracking software in adults

    DEFF Research Database (Denmark)

    Risum, Niels; Ali, Sophia; Olsen, Niels T

    2012-01-01

    Evaluation of myocardial deformation by two-dimensional speckle-tracking is useful for clinical and research purposes. However, differences may exist among different ultrasound machines, software packages, frame rates, and observers....

  18. Speckle-tracking echocardiography for predicting outcome in chronic aortic regurgitation during conservative management and after surgery

    DEFF Research Database (Denmark)

    Olsen, Niels Thue; Søgaard, Peter; Larsson, Henrik B W

    2011-01-01

    . Speckle-tracking echocardiography has been proposed for this purpose, but the clinical value of this method in aortic regurgitation has not been established. Methods A longitudinal study was performed in 64 patients with moderate to severe aortic regurgitation. Thirty-five patients were managed...... conservatively with frequent clinical visits and sequential echocardiography and followed for an average of 19 ± 8 months, while 29 patients underwent surgery for the valve lesion and were followed for 6 months post-operatively. Baseline LV function by speckle-tracking and conventional echocardiography...... was compared with impaired outcome after surgery (defined as persisting symptoms or persisting LV dilation [LV end-diastolic volume index =87 ml/m2] or dysfunction [LV ejection fraction management (defined as development of symptoms, increase in LV volume...

  19. Speckle-Tracking Strain Imaging Identifies Alterations in Left Atrial Mechanics With General Anesthesia and Positive-Pressure Ventilation.

    Science.gov (United States)

    Howard-Quijano, Kimberly; Anderson-Dam, John; McCabe, Melissa; Hall, Michael; Mazor, Einat; Mahajan, Aman

    2015-08-01

    The primary aim of this study was to use speckle-tracking strain imaging to evaluate the effect of general anesthesia (GA) and positive-pressure ventilation (PPV) on left atrial (LA) mechanics. The authors hypothesized that GA and PPV would be associated with a decrease in LA strain. The secondary aims were to investigate the effects of GA and PPV on traditional Doppler-derived measures of LA function and Doppler echocardiographic grade of diastolic function. A prospective observational study. A university hospital. Adult patients undergoing cardiac surgery. Transthoracic echocardiography was performed at baseline and under GA with PPV. Changes in LA function associated with GA and PPV were assessed using LA speckle-tracking strain imaging. A reduction was observed in LA peak longitudinal strain (24% v 18%, pmechanics by decreasing strain measures of LA preload, with a lesser effect on LA contractility. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. Speckle tracking echocardiography in chronic obstructive pulmonary disease and overlapping obstructive sleep apnea.

    Science.gov (United States)

    Pizarro, Carmen; van Essen, Fabian; Linnhoff, Fabian; Schueler, Robert; Hammerstingl, Christoph; Nickenig, Georg; Skowasch, Dirk; Weber, Marcel

    2016-01-01

    COPD and congestive heart failure represent two disease entities of growing global burden that share common etiological features. Therefore, we aimed to identify the degree of left ventricular (LV) dysfunction in COPD as a function of COPD severity stages and concurrently placed particular emphasis on the presence of overlapping obstructive sleep apnea (OSA). A total of 85 COPD outpatients (64.1±10.4 years, 54.1% males) and 20 controls, matched for age, sex, and smoking habits, underwent speckle tracking echocardiography for LV longitudinal strain imaging. Complementary 12-lead electrocardiography, laboratory testing, and overnight screening for sleep-disordered breathing using the SOMNOcheck micro(®) device were performed. Contrary to conventional echocardiographic parameters, speckle tracking echocardiography revealed significant impairment in global LV strain among COPD patients compared to control smokers (-13.3%±5.4% vs -17.1%±1.8%, P=0.04). On a regional level, the apical septal LV strain was reduced in COPD (P=0.003) and associated with the degree of COPD severity (P=0.02). With regard to electrocardiographic findings, COPD patients exhibited a significantly higher mean heart rate than controls (71.4±13.0 beats per minute vs 60.3±7.7 beats per minute, P=0.001) that additionally increased over Global Initiative for Chronic Obstructive Lung Disease stages (P=0.01). Albeit not statistically significant, COPD led to elevated N-terminal pro-brain natriuretic peptide levels (453.2±909.0 pg/mL vs 96.8±70.0 pg/mL, P=0.08). As to somnological testing, the portion of COPD patients exhibiting overlapping OSA accounted for 5.9% and did not significantly vary either in comparison to controls (P=0.07) or throughout the COPD Global Initiative for Chronic Obstructive Lung Disease stages (P=0.49). COPD-OSA overlap solely correlated with nocturnal hypoxemic events, whereas LV performance status was unrelated to coexisting OSA. To conclude, COPD itself seems to be

  1. Valoración de la función del apéndice auricular izquierdo por speckle tracking

    Directory of Open Access Journals (Sweden)

    Jairo A. Rendón

    2014-05-01

    Conclusión: La valoración de la función del apéndice auricular izquierdo por medio de speckle tracking, es una herramienta útil para caracterizar la función de esta estructura; su alteración se podría relacionar con el riesgo de desarrollar trombos y eventos embólicos secundarios.

  2. Speckle tracking echocardiographic analysis of left ventricular systolic and diastolic function in young elite rugby players.

    Science.gov (United States)

    Mandigout, Stéphane; Maufrais, Claire; Cornette, Thibault; Alaphilippe, Anne; Daviet, Jean C

    2016-11-01

    Little evidence exists in the literature on the effects of mixed-type training on the left ventricle (LV). This study focused on the effects of training on the morphological and functional characteristics of the left ventricle. This study investigated the effects of training on LV function using Speckle Tracking Imaging (STI) in high-level, young rugby players. This prospective and longitudinal cohort study enrolled ten young controls and 24 young rugby players (13 high-level rugby players; 11 amateur rugby players) were included in the study. Standard Tissue Doppler Imaging Echocardiography and STI were performed in this study before and after the season. LV mass and pulsed wave Doppler inflow recording of the LV, including early and atrial waves, were carried out in 2-3-4 chamber views. We assessed three normal strains, rotation, and torsion in the LV. The main results of this study demonstrated that no differences existed between the three groups in LV functional parameters, the longitudinal circumferential and radial strain indices, and rotation and torsion indices. In the professional group, a significantly higher end-diastolic diameter (Prugby players have normal LV remodeling and normal LV function under resting conditions.

  3. Early detection of cardiac involvement in sarcoidosis with 2-dimensional speckle-tracking echocardiography.

    Science.gov (United States)

    Schouver, Elie-Dan; Moceri, Pamela; Doyen, Denis; Tieulie, Nathalie; Queyrel, Viviane; Baudouy, Delphine; Cerboni, Pierre; Gibelin, Pierre; Leroy, Sylvie; Fuzibet, Jean-Gabriel; Ferrari, Emile

    2017-01-15

    Cardiac sarcoidosis (CS) is associated with high morbidity and sudden death. The absence of specific symptoms and lack of diagnostic gold standard technique is challenging. New imaging methods could improve the diagnosis of CS. The aim of our study was to assess the role of left ventricular (LV) longitudinal and circumferential strain as estimated by 2D speckle-tracking imaging in patients with diagnosed sarcoidosis without cardiac involvement according to the current guidelines. We investigated the prevalence of LV strain impairment in this population and assessed its relationship with clinical outcomes, composite of mortality, heart failure, arrhythmia and/or secondarily development of CS and cardiac device implantation. We performed a prospective case-control longitudinal study including 35 patients with diagnosed sarcoidosis and normal cardiac function as assessed by standard transthoracic echocardiography and 35 healthy age- and gender-matched controls. All patients underwent a comprehensive echocardiographic study. Mean age of patients was 47.9±14.8years old (22 women). Compared with controls, global LV longitudinal strain (LV GLS) was reduced in sarcoidosis patients: (-17.2±3.1 vs -21.3±1.5%, psarcoidosis patients that was associated with outcomes. LV GLS may represent an early marker of myocardial involvement in sarcoidosis patients that needs to be studied further. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  4. Speckle Tracking Based Strain Analysis Is Sensitive for Early Detection of Pathological Cardiac Hypertrophy.

    Science.gov (United States)

    An, Xiangbo; Wang, Jingjing; Li, Hao; Lu, Zhizhen; Bai, Yan; Xiao, Han; Zhang, Youyi; Song, Yao

    2016-01-01

    Cardiac hypertrophy is a key pathological process of many cardiac diseases. However, early detection of cardiac hypertrophy is difficult by the currently used non-invasive method and new approaches are in urgent need for efficient diagnosis of cardiac malfunction. Here we report that speckle tracking-based strain analysis is more sensitive than conventional echocardiography for early detection of pathological cardiac hypertrophy in the isoproterenol (ISO) mouse model. Pathological hypertrophy was induced by a single subcutaneous injection of ISO. Physiological cardiac hypertrophy was established by daily treadmill exercise for six weeks. Strain analysis, including radial strain (RS), radial strain rate (RSR) and longitudinal strain (LS), showed marked decrease as early as 3 days after ISO injection. Moreover, unlike the regional changes in cardiac infarction, strain analysis revealed global cardiac dysfunction that affects the entire heart in ISO-induced hypertrophy. In contrast, conventional echocardiography, only detected altered E/E', an index reflecting cardiac diastolic function, at 7 days after ISO injection. No change was detected on fractional shortening (FS), E/A and E'/A' at 3 days or 7 days after ISO injection. Interestingly, strain analysis revealed cardiac dysfunction only in ISO-induced pathological hypertrophy but not the physiological hypertrophy induced by exercise. Taken together, our study indicates that strain analysis offers a more sensitive approach for early detection of cardiac dysfunction than conventional echocardiography. Moreover, multiple strain readouts distinguish pathological cardiac hypertrophy from physiological hypertrophy.

  5. Speckle tracking echocardiography to assess regional ventricular function in patients with apical hypertrophic cardiomyopathy

    Science.gov (United States)

    Saccheri, María Cristina; Cianciulli, Tomás Francisco; Morita, Luis Alberto; Méndez, Ricardo José; Beck, Martín Alejandro; Guerra, Juan Enrique; Cozzarin, Alberto; Puente, Luciana Jimena; Balletti, Lorena Romina; Lax, Jorge Alberto

    2017-01-01

    AIM To explore regional systolic strain of midwall and endocardial segments using speckle tracking echocardiography in patients with apical hypertrophic cardiomyopathy (HCM). METHODS We prospectively assessed 20 patients (mean age 53 ± 16 years, range: 18-81 years, 10 were male), with apical HCM. We measured global longitudinal peak systolic strain (GLPSS) in the midwall and endocardium of the left ventricle. RESULTS The diastolic thickness of the 4 apical segments was 16.25 ± 2.75 mm. All patients had a normal global systolic function with a fractional shortening of 50% ± 8%. In spite of supernormal left ventricular (LV) systolic function, midwall GLPSS was decreased in all patients, more in the apical (-7.3% ± -8.8%) than in basal segments (-15.5% ± -6.93%), while endocardial GLPPS was significantly greater and reached normal values (apical: -22.8% ± -7.8%, basal: -17.9% ± -7.5%). CONCLUSION This study shows that two-dimensional strain was decreased mainly confined to the mesocardium, while endocardium myocardial deformation was preserved in HCM and allowed to identify subclinical LV dysfunction. This transmural heterogeneity in systolic strain had not been previously described in HCM and could be explained by the distribution of myofibrillar disarray in deep myocardial areas. The clinical application of this novel finding may help further understanding of the pathophysiology of HCM. PMID:28515855

  6. Assessment of subendocardial contractile function in aortic stenosis: a study using speckle tracking echocardiography.

    Science.gov (United States)

    van Dalen, Bas M; Tzikas, Apostolos; Soliman, Osama I I; Heuvelman, Helena J; Vletter, Wim B; Ten Cate, Folkert J; Geleijnse, Marcel L

    2013-03-01

    Angina and an electrocardiographic strain pattern are potential manifestations of subendocardial ischemia in aortic stenosis (AS). Left ventricular (LV) twist is known to increase proportionally to the severity of AS, which may be a result of loss of the inhibiting effect of the subendocardial fibers due to subendocardial dysfunction. It has also been shown that the ratio of LV twist to circumferential shortening of the endocardium (twist-to-shortening ratio [TSR]) is a reliable parameter of subendocardial dysfunction. The aim of this study was to investigate whether these markers are increased in AS patients with angina and/or electrocardiographic strain. The study comprised 60 AS patients with an aortic valve area 50%, and 30 healthy-for age and gender matched-control subjects. LV rotation parameters were determined by speckle tracking echocardiography. Comparison of patients without angina and strain (n = 22), with either angina or strain (n = 28), and with both angina and strain (n = 8), showed highest peak systolic LV apical rotation, peak systolic LV twist, and TSR, in patients with more signs of subendocardial ischemia. In a multivariate linear regression model, only severity of AS and the presence of angina and/or strain could be identified as independent predictors of peak systolic LV twist and TSR. Peak systolic LV twist and TSR are increased in AS patients and related to the severity of AS and symptoms (angina) or electrocardiographic signs (strain) compatible with subendocardial ischemia. © 2013, Wiley Periodicals, Inc.

  7. Speckle variance full-field optical coherence microscopy for high-resolution microvasculature mapping

    Science.gov (United States)

    Ogien, Jonas; Dubois, Arnaud

    2017-02-01

    This work reports on the feasibility of dynamic imaging using conventional reflectivity-based tomographic images obtained with full-field optical coherence microscopy (FF-OCM). Implementation of speckle variance for flow mapping with an imaging rate of 180 Hz is demonstrated by mapping 20% intralipid flowing into 100-μm-diameter microcapillary tubes at speeds up to 50 mm/s. This constitutes a significant advance in high-resolution, real-time microvasculature mapping, using FF-OCM. The acquisition scheme in FF-OCM is particularly appropriate for en face visualization of the microvasculature, as FF-OCM directly acquires en face tomographic images unlike conventional OCT which usually requires reslicing of a three-dimensional data set to get en face images.

  8. Speckle tracking echocardiography in acute lupus myocarditis: comparison to conventional echocardiography

    Directory of Open Access Journals (Sweden)

    Riëtte Du Toit

    2017-07-01

    Full Text Available Aims: Lupus myocarditis occurs in 5–10% of patients with systemic lupus erythematosus (SLE. No single feature is diagnostic of lupus myocarditis. Speckle tracking echocardiography (STE can detect subclinical left ventricular dysfunction in SLE patients, with limited research on its utility in clinical lupus myocarditis. We report on STE in comparison to conventional echocardiography in patients with clinical lupus myocarditis. Methods and results: A retrospective study was done at a tertiary referral hospital in South Africa. SLE patients with lupus myocarditis were included and compared to healthy controls. Echocardiographic images were reanalyzed, including global longitudinal strain through STE. A poor echocardiographic outcome was defined as final left ventricular ejection fraction (LVEF <40%. 28 SLE patients fulfilled the criteria. Global longitudinal strain correlated with global (LVEF: r = −0.808; P = 0.001 and regional (wall motion score: r = 0.715; P < 0.001 function. In patients presenting with a LVEF ≥50%, global longitudinal strain (P = 0.023, wall motion score (P = 0.005 and diastolic function (P = 0.004 were significantly impaired vs controls. Following treatment, LVEF (35–47% (P = 0.023 and wall motion score (1.88–1.5 (P = 0.017 improved but not global longitudinal strain. Initial LVEF (34%; P = 0.046 and global longitudinal strain (−9.5%; P = 0.095 were lower in patients with a final LVEF <40%. Conclusions: This is the first known report on STE in a series of patients with clinical lupus myocarditis. Global longitudinal strain correlated with regional and global left ventricular function. Global longitudinal strain, wall motion score and diastolic parameters may be more sensitive markers of lupus myocarditis in patients presenting with a preserved LVEF ≥50%. A poor initial LVEF and global longitudinal strain were associated with a persistent LVEF <40%. Echocardiography is a non-invasive tool with diagnostic and

  9. Longitudinal Strain by Speckle Tracking Echocardiography in Pediatric Heart Transplant Recipients.

    Science.gov (United States)

    Buddhe, Sujatha; Richmond, Marc E; Gilbreth, John; Lai, Wyman W

    2015-01-01

    Heart transplant recipients are at risk for developing left ventricular (LV) dysfunction. While traditional echocardiographic parameters have limitations, speckle tracking echocardiography (STE) is a novel technique shown to be more sensitive and accurate in adult studies for evaluating ventricular systolic and diastolic function. Pediatric heart transplant recipients undergoing routine cardiac catheterization were included. Ratio of mitral early diastolic velocity-to-strain rate during early LV filling (E/SR(E)) and global longitudinal peak systolic strain (GLPSS) was measured by STE imaging. These were compared with wedge pressures by catheterization and traditional echocardiographic parameters. A total of 50 subjects (46% males) were included. Mean age of the subjects was 13.0 ± 6.3 years and time since transplant was 4.1 years (range 0.2-17.1 years). While peak mitral inflow to late diastolic velocity (E/A ratio) was the only traditional diastolic function parameter having significant correlation with pulmonary capillary wedge pressure (PCWP) (r = 0.3; P = .3), STE-derived E/SR(E) had modest correlation with PCWP (r = 0.55; P -18%. Interestingly, subjects with coronary artery disease (n = 6) had significantly higher E/SR(E) (71.9 ± 28.4) compared to subjects without (45.2 ± 10.8; P < .001). Diastolic function parameters by STE imaging correlate better with gold standard PCWP measurement than traditional echocardiographic parameters. Also, utilizing STE, abnormalities of longitudinal LV systolic function may be more common than previously thought in pediatric heart transplant recipients without acute graft rejection, despite "normal" systolic function by traditional echocardiogram. © 2015 Wiley Periodicals, Inc.

  10. Strain and strain rate by two-dimensional speckle tracking echocardiography in a maned wolf

    Directory of Open Access Journals (Sweden)

    Matheus M. Mantovani

    2012-12-01

    Full Text Available The measurement of cardiovascular features of wild animals is important, as is the measurement in pets, for the assessment of myocardial function and the early detection of cardiac abnormalities, which could progress to heart failure. Speckle tracking echocardiography (2D STE is a new tool that has been used in veterinary medicine, which demonstrates several advantages, such as angle independence and the possibility to provide the early diagnosis of myocardial alterations. The aim of this study was to evaluate the left myocardial function in a maned wolf by 2D STE. Thus, the longitudinal, circumferential and radial strain and strain rate were obtained, as well as, the radial and longitudinal velocity and displacement values, from the right parasternal long axis four-chamber view, the left parasternal apical four chamber view and the parasternal short axis at the level of the papillary muscles. The results of the longitudinal variables were -13.52±7.88, -1.60±1.05, 4.34±2.52 and 3.86±3.04 for strain (%, strain rate (1/s, displacement (mm and velocity (cm/s, respectively. In addition, the radial and circumferential Strain and Strain rate were 24.39±14.23, 1.86±0.95 and -13.69±6.53, -1.01±0.48, respectively. Thus, the present study provides the first data regarding the use of this tool in maned wolves, allowing a more complete quantification of myocardial function in this species.

  11. Two-dimensional speckle-tracking echocardiography reveals systolic abnormalities in granulomatosis with polyangiitis (Wegener's).

    Science.gov (United States)

    Miszalski-Jamka, Tomasz; Szczeklik, Wojciech; Nycz, Krzysztof; Sokołowska, Barbara; Górka, Jacek; Bury, Krzysztof; Musiał, Jacek

    2012-08-01

    Two-dimensional speckle-tracking echocardiography (STE) is a novel technique providing accurate assessment of myocardial function. However, its value in granulomatosis with polyangiitis (Wegener's) (WG) has not been studied. To assess the presence and frequency of systolic left ventricular (LV) dysfunction using STE and to determine incremental value of STE over standard echocardiography to detect myocardial abnormalities in WG. Twenty-two WG patients (11 males, 11 females, mean age 46.8 ± 12.3 years) and 22 sex- and age-matched healthy subjects underwent standard and STE. Global longitudinal, circumferential, and rotational deformation parameters were calculated. All patients had LV ejection fraction (EF) >50%. LVEF was 65.0 ± 7.5% and LV end-diastolic volume index 44.8 ± 11.8 mL/m(2) . Regional LV wall motion abnormalities were found in 7 (32%), while abnormal global STE determined systolic dysfunction in 16 (73%) subjects (P = 0.008). Global longitudinal, circumferential and radial peak-systolic deformational parameters (strain or strain rate) were decreased in 11 (50%), 9 (41%), and 3 (14%) patients (P = 0.02), respectively. Comparing patients with abnormal and normal STE derived global systolic function, the former had higher cumulative disease extent index (10.6 ± 3.0 vs 7.5 ± 1.8; P = 0.03) and vasculitis damage index (7.9 ± 1.9 vs 6.0 ± 1.7; P = 0.04). Despite normal LVEF the global systolic LV abnormalities detected by STE are common in WG. They correspond to the extent and severity of WG and are more frequent than regional wall motion abnormalities in standard echocardiography. © 2012, Wiley Periodicals, Inc.

  12. Detection of small subendocardial infarction using speckle tracking echocardiography in a rat model.

    Science.gov (United States)

    Bachner-Hinenzon, Noa; Shlomo, Liron; Khamis, Hanan; Ertracht, Offir; Vered, Zvi; Malka, Assaf; Binah, Ofer; Adam, Dan

    2016-10-01

    It is challenging to detect small nontransmural infarcts visually or automatically. As it is important to detect myocardial infarction (MI) at early stages, we tested the hypothesis that small nontransmural MI can be detected using speckle tracking echocardiography (STE) at the acute stage. Minimal nontransmural infarcts were induced in 18 rats by causing recurrent ischemia-reperfusion of the left anterior descending (LAD) coronary artery, followed by a 30-min ligation and by reperfusion. A week later, the scar size was measured by histological analysis. Each rat underwent three echocardiography measurements: at baseline, 1 day post-MI, and 1 week post-MI. To measure the peak circumferential strain (CS), peak systolic CS, radial strain (RS), and time-to-peak (TTP) of the CS, short-axis view of the apex was analyzed by a STE program. The TTP was normalized by the duration of the heart cycle to create percent change of heart cycle. Histological analysis after 1 week showed scar size of 4±6% at the anterior wall. At 24 h post-MI, the peak CS, peak systolic CS, and RS were reduced compared to baseline at the anterior wall due to the MI, and at the adjacent segments-the anterior septum and lateral wall, due to stunning (P<.05). However, only the anterior wall, the genuine damaged segment, showed prolonged TTP vs baseline (baseline 36%, 24 h 48%, P<.05). The TTP of the CS can distinguish between regions adjacent to MI (stunned or tethered) and MI, even in small nontransmural infarcts. © 2016, Wiley Periodicals, Inc.

  13. Feasibility, Reproducibility, and Agreement between Different Speckle Tracking Echocardiographic Techniques for the Assessment of Longitudinal Deformation

    Directory of Open Access Journals (Sweden)

    Sergio Buccheri

    2013-01-01

    Full Text Available Background. Left ventricular (LV longitudinal deformation can be assessed with new echocardiographic techniques like triplane echocardiography (3PE and four-dimensional echocardiography (4DE. We aimed to assess the feasibility, reproducibility, and agreement between these different speckle-tracking techniques for the assessment of longitudinal deformation. Methods. 101 consecutive subjects underwent echocardiographic examination. 2D cine loops from the apical views, a triplane view, and an LV 4D full volume were acquired in all subjects. LV longitudinal strain was obtained for each imaging modality. Results. 2DE analysis of LV strain was feasible in 90/101 subjects, 3PE strain in 89/101, and 4DE strain in 90/101. The mean value of 2DE and 3PE longitudinal strains was significantly higher with respect to 4DE. The relationship between 2DE and 3PE derived strains (r=0.782 was significantly higher (z=3.72, P<0.001 than that between 2DE and 4DE (r=0.429 and that between 3PE and 4DE (r=0.510; z=3.09, P=0.001. The mean bias between 2DE and 4DE strains was -6.61±7.31% while -6.42±6.81% between 3PE and 4DE strains; the bias between 2DE and 3PE strain was of 0.21±4.16%. Intraobserver and interobserver variabilities were acceptable among the techniques. Conclusions. Echocardiographic techniques for the assessment of longitudinal deformation are not interchangeable, and further studies are needed to assess specific reference values.

  14. Comet Shoemaker-Levy 9/Jupiter collision observed with a high resolution speckle imaging system

    Energy Technology Data Exchange (ETDEWEB)

    Gravel, D. [Lawrence Livermore National Lab., CA (United States)

    1994-11-15

    During the week of July 16, 1994, comet Shoemaker-Levy 9, broken into 20 plus pieces by tidal forces on its last orbit, smashed into the planet Jupiter, releasing the explosive energy of 500 thousand megatons. A team of observers from LLNL used the LLNL Speckle Imaging Camera mounted on the University of California`s Lick Observatory 3 Meter Telescope to capture continuous sequences of planet images during the comet encounter. Post processing with the bispectral phase reconstruction algorithm improves the resolution by removing much of the blurring due to atmospheric turbulence. High resolution images of the planet surface showing the aftermath of the impact are probably the best that were obtained from any ground-based telescope. We have been looking at the regions of the fragment impacts to try to discern any dynamic behavior of the spots left on Jupiter`s cloud tops. Such information can lead to conclusions about the nature of the comet and of Jupiter`s atmosphere. So far, the Hubble Space Telescope has observed expanding waves from the G impact whose mechanism is enigmatic since they appear to be too slow to be sound waves and too fast to be gravity waves, given the present knowledge of Jupiter`s atmosphere. Some of our data on the G and L impact region complements the Hubble observations but, so far, is inconclusive about spot dynamics.

  15. Three-dimensional Speckle Tracking Echocardiography in Light Chain Cardiac Amyloidosis: Examination of Left and Right Ventricular Myocardial Mechanics Parameters.

    Science.gov (United States)

    Urbano-Moral, Jose Angel; Gangadharamurthy, Dakshin; Comenzo, Raymond L; Pandian, Natesa G; Patel, Ayan R

    2015-08-01

    The study of myocardial mechanics has a potential role in the detection of cardiac involvement in patients with amyloidosis. This study aimed to characterize 3-dimensional-speckle tracking echocardiography-derived left and right ventricular myocardial mechanics in light chain amyloidosis and examine their relationship with brain natriuretic peptide. In patients with light chain amyloidosis, left ventricular longitudinal and circumferential strain (n=40), and right ventricular longitudinal strain and radial displacement (n=26) were obtained by 3-dimensional-speckle tracking echocardiography. Brain natriuretic peptide levels were determined. All myocardial mechanics measurements showed differences when compared by brain natriuretic peptide level tertiles. Left and right ventricular longitudinal strain were highly correlated (r=0.95, P<.001). Left ventricular longitudinal and circumferential strain were reduced in patients with cardiac involvement (-9±4 vs -16±2; P<.001, and -24±6 vs -29±4; P=.01, respectively), with the most prominent impairment at the basal segments. Right ventricular longitudinal strain and radial displacement were diminished in patients with cardiac involvement (-9±3 vs -17±3; P<.001, and 2.7±0.8 vs 3.8±0.3; P=.002). On multivariate analysis, left ventricular longitudinal strain was associated with the presence of cardiac involvement (odds ratio = 1.6; 95% confidence interval, 1.04 to 2.37; P=.03) independent of the presence of brain natriuretic peptide and troponin I criteria for cardiac amyloidosis. Three-dimensional-speckle tracking echocardiography-derived left and right ventricular myocardial mechanics are increasingly altered as brain natriuretic peptide increases in light chain amyloidosis. There appears to be a strong association between left ventricular longitudinal strain and cardiac involvement, beyond biomarkers such as brain natriuretic peptide and troponin I. Copyright © 2015 Sociedad Española de Cardiología. Published by

  16. Quantification of global myocardial function by cine MRI deformable registration-based analysis: Comparison with MR feature tracking and speckle-tracking echocardiography.

    Science.gov (United States)

    Lamacie, Mariana M; Thavendiranathan, Paaladinesh; Hanneman, Kate; Greiser, Andreas; Jolly, Marie-Pierre; Ward, Richard; Wintersperger, Bernd J

    2017-04-01

    To evaluate deformable registration algorithms (DRA)-based quantification of cine steady-state free-precession (SSFP) for myocardial strain assessment in comparison with feature-tracking (FT) and speckle-tracking echocardiography (STE). Data sets of 28 patients/10 volunteers, undergoing same-day 1.5T cardiac MRI and echocardiography were included. LV global longitudinal (GLS), circumferential (GCS) and radial (GRS) peak systolic strain were assessed on cine SSFP data using commercially available FT algorithms and prototype DRA-based algorithms. STE was applied as standard of reference for accuracy, precision and intra-/interobserver reproducibility testing. DRA showed narrower limits of agreement compared to STE for GLS (-4.0 [-0.9,-7.9]) and GCS (-5.1 [1.1,-11.2]) than FT (3.2 [11.2,-4.9]; 3.8 [13.9,-6.3], respectively). While both DRA and FT demonstrated significant differences to STE for GLS and GCS (all pcine MRI. • Inverse DRA demonstrated superior reproducibility compared to feature-tracking (FT) methods. • Cine MR DRA and FT analysis demonstrate differences to speckle-tracking echocardiography • DRA demonstrated better correlation with STE than FT for MR-derived global strain data.

  17. Estudo da Mecânica Cardíaca pelo Speckle Tracking

    OpenAIRE

    Maria Cristina Donadio Abduch; Adriano Mesquita Alencar; Wilson Mathias Jr; Marcelo Luiz Campos Vieira

    2014-01-01

    Speckles, ou marcadores naturais do miocárdio, originam se da interferência construtiva e destrutiva do feixe de ultrassom que incide sobre os tecidos, podem fornecer um diagnóstico precoce das alterações miocárdicas e atuar na predição de certos eventos cardíacos. Devido à sua relativa estabilidade temporal, os speckles podem ser rastreados durante o ciclo cardíaco por software dedicados, promovendo a análise da função sistólica e diastólica. São identificados tanto pela escala de cinza da e...

  18. Deformação miocárdica pelo speckle tracking na cardiomiopatia dilatada grave

    Directory of Open Access Journals (Sweden)

    Maria Cristina Donadio Abduch

    2012-09-01

    Full Text Available FUNDAMENTO: A alta e crescente prevalência de Cardiomiopatia Dilatada (CMD representa sério problema de saúde pública. Novas tecnologias vêm sendo utilizadas objetivando diagnósticos mais sofisticados, que melhorem a abordagem terapêutica. Nesse cenário, o Speckle Tracking (STE utiliza marcadores miocárdicos naturais para analisar a deformação sistólica do Ventrículo Esquerdo (VE. OBJETIVO: Mensurar o strain transmural longitudinal global (SG do VE através do STE em pacientes com CMD grave, comparando os resultados com indivíduos normais e com parâmetros ecocardiográficos consagrados para análise da função sistólica do VE, validando o método nessa população. MÉTODOS: Foram estudados 71 pacientes com CMD grave, (53 ± 12a, 72% homens e 20 controles (30 ± 8a, 45% homens. Foram obtidos os volumes e a FEVE pela ecocardiografia bi e tridimensional, parâmetros do Doppler, Doppler tecidual e o SG pelo STE. RESULTADOS: Comparados ao grupo controle, os volumes do VE foram maiores no grupo CMD; entretanto, a FEVE e velocidade de pico da onda E foram menores neste último. O índice de performance miocárdica foi maior entre os pacientes. As velocidades do miocárdio pelo Doppler tecidual (S', e', a' foram consideravelmente menores e a relação E/e' foi maior no grupo CMD. O SG apresentou-se diminuído no grupo CMD (-5,5% ± 2,3%, em relação aos controles (-14,0% ± 1,8%. CONCLUSÃO: No presente estudo, o SG foi significativamente menor nos pacientes com CMD grave, abrindo novas perspectivas para abordagens terapêuticas nessa população específica.

  19. Descending aortic mechanics and atrial fibrillation: a two-dimensional speckle tracking transesophageal echocardiography study.

    Science.gov (United States)

    Teixeira, Rogério; Monteiro, Ricardo; Dinis, Paulo; Santos, Maria José; Botelho, Ana; Quintal, Nuno; Cardim, Nuno; Gonçalves, Lino

    2017-04-01

    Vascular mechanics assessed with two-dimensional speckle tracking echocardiography (2D-STE) could be used as a new imaging surrogate of vascular stiffening. The CHA2DS2-VASc score is considered accurate as an estimate of stroke risk in non-valvular AF, although many potential stroke risk factors have not been included in this scoring method. The purpose of this research is to study the feasibility of evaluating vascular mechanics at the descending aorta in non-valvular AF patients using transesophageal 2D-STE and to analyze the association between descending aortic mechanics and stroke. We prospectively recruited a group of 44 patients referred for a transesophageal echocardiogram (TEE) in the context of cardioversion for non-valvular AF. A short-axis view of the descending aorta, one to two centimeters after the aortic arch was selected for the vascular mechanics assessment with the 2D-STE methodology. The vascular mechanics parameters analyzed were circumferential aortic strain (CAS) and early circumferential aortic strain rate (CASR). A clinical assessment was performed with focus on the past stroke history and the CHA2DS2-VASc score. The mean age of our cohort was 65 ± 13 years and 75% were men; AF was known for 2.8 ± 2.5 years and it was considered paroxystic in 41% of cases. Waveforms adequate for measuring 2D-STE were present in 85% of the 264 descending aortic wall segments. The mean CAS was 3.5 ± 1.2% and the mean CASR was 0.7 ± 0.3 s-1. The inter- and intra-observer variability for aortic mechanics was considered adequate. The median CHA2DS2VASc score was 2 (2-3). As the score increased we noted that both the CAS (r = -0.38, P = 0.01) and the CASR (r = -0.42, P mechanics assessed with transesophageal 2D-STE.

  20. Speckle tracking and myocardial tissue imaging in infant of diabetic mother with gestational and pregestational diabetes.

    Science.gov (United States)

    Al-Biltagi, Mohammed; Tolba, Osama Abd Rab Elrasoul; Rowisha, Mohamed Ahmed; Mahfouz, Amal El-Sayed; Elewa, Mona Ahmed

    2015-02-01

    The aim of this study was to evaluate the myocardial changes in infants of diabetic mother either with gestational or pregestational diabetes and its relation to maternal diabetic control. The study included 45 infants of diabetic mother (IDMs) and 45 healthy newborn as a control group. IDMs were then categorized into 2 subgroups: twenty infants of mother with pregestational diabetes and twenty-five infants of mothers with gestational diabetes. The studied groups underwent measurement of the maternal and neonatal glycated Hb % (HbA1c), conventional echocardiography, tissue Doppler imaging (TDI) and two-dimensional speckle tracking imaging (STI). The weight, the rate of complications, and the rate of cesarean section were significantly higher in the IDMs group than in the control group. Significant positive correlation was present between the levels of HbA1c of IDMs and HbA1c of their mothers (P IDMs with both pre-gestational and gestational diabetes compared with the control group. Also, the septal/posterior wall ratio (SW/PW) was significantly higher in pregestational (1.86 ± 0.3) and gestational (2 ± 0.4) groups than in the control group (1 ± 0.06). Two-dimensional STI showed that the cardiac torsion was significantly impaired in pre-gestational (9.66 ± 2.5) and gestational (8.66 ± 3.9) groups when compared with the control group (5.4 ± 2.4) [P IDMs especially in infants of mother with pre-gestational diabetes. All the previous TDI findings did not show any significant correlation to neither maternal nor fetal HbA1c. Also, there was no significant correlation between cardiac torsion and the rest of TDI data neither in IDMs group nor in the control group. TDI and two-dimensional STI were efficient and sensitive tools able to early detect cardiac dysfunction in IDMs even in the absence of morphologic cardiac changes.

  1. The relationship between tricuspid regurgitation severity and right atrial mechanics: a speckle tracking echocardiography study.

    Science.gov (United States)

    Teixeira, Rogério; Monteiro, Ricardo; Garcia, João; Baptista, Rui; Ribeiro, Miguel; Cardim, Nuno; Gonçalves, Lino

    2015-08-01

    The aim at this study was to assess the influence of the tricuspid regurgitation volume (TRvol) in right atrium (RA) reservoir phase myocardial mechanics. We included 55 heart failure (HF) patients referred for transthoracic echocardiography during a 2-month period. 18 Had HF with a reduced ejection fraction (HFREF) and 37 HF with a preserved ejection fraction (HFPEF). TR was chronic and functional. TRvol was calculated according to the PISA method. This study of RA used 2D-speckle tracking echocardiography to measure strain (rεR) and strain rate (rSR(R)). The reference frame coincided with the onset of the QRS. RA stiffness was assessed as the ratio: (rE/e')/rε(R). The median age of the sample was 78 (64-84) years, with female gender predominance (63.6%). The median value of rε(R) was 16% (range, 12.7-24.0) and of rSR(R) was 1.57 s(-1) (range, 1.09-2.05). We observed a significant negative correlation between rε(R) (r = -0.68, p < 0.01) and rSR(R) (r = -0.58, p < 0.01) and TRvol. RA mechanics decreased significantly with an increase in the TR grade. We created two multivariate linear regression models for rε(R) and rSR(R), separately for the patients with sinus rhythm or atrial fibrillation. The TRvol was independently associated with rε(R) after adjusting to the RA area, right ventricular longitudinal systolic function and the estimated pulmonary vascular resistance. We demonstrated an increase in RA stiffness with an increase in TR severity, and an association for functional status (NYHA class) and RA compliance. The HFREF group had a significantly lower rε(R) and rSR(R) that the HFPEF patients. According to our study, in HF patients, a chronic volume overload state significantly reduced the RA reservoir phase mechanics.

  2. Adapting high-resolution speckle imaging to moving targets and platforms

    Energy Technology Data Exchange (ETDEWEB)

    Carrano, C J; Brase, J M

    2004-02-05

    High-resolution surveillance imaging with apertures greater than a few inches over horizontal or slant paths at optical or infrared wavelengths will typically be limited by atmospheric aberrations. With static targets and static platforms, we have previously demonstrated near-diffraction limited imaging of various targets including personnel and vehicles over horizontal and slant paths ranging from less than a kilometer to many tens of kilometers using adaptations to bispectral speckle imaging techniques. Nominally, these image processing methods require the target to be static with respect to its background during the data acquisition since multiple frames are required. To obtain a sufficient number of frames and also to allow the atmosphere to decorrelate between frames, data acquisition times on the order of one second are needed. Modifications to the original imaging algorithm will be needed to deal with situations where there is relative target to background motion. In this paper, we present an extension of these imaging techniques to accommodate mobile platforms and moving targets.

  3. Capillary detectors for high resolution tracking

    CERN Document Server

    Annis, P

    1997-01-01

    We present a new tracking device based on glass capillary bundles or layers filled with highly purified liquid scintillator and read out at one end by means of image intensifiers and CCD devices. A large-volume prototype consisting of 5 × 105 capillaries with a diameter of 20 μm and a length of 180 cm and read out by a megapixel CCD has been tested with muon and neutrino beams at CERN. With this prototype a two track resolution of 33 μm was achieved with passing through muons. Images of neutrino interactions in a capillary bundle have also been acquired and analysed. Read-out chains based on Electron Bombarded CCD (EBCCD) and image pipeline devices are also investigated. Preliminary results obtained with a capillary bundle read out by an EBCCD are presented.

  4. Determination of multidirectional myocardial deformations in cats with hypertrophic cardiomyopathy by using two-dimensional speckle-tracking echocardiography.

    Science.gov (United States)

    Suzuki, Ryohei; Mochizuki, Yohei; Yoshimatsu, Hiroki; Teshima, Takahiro; Matsumoto, Hirotaka; Koyama, Hidekazu

    2017-12-01

    Objectives Hypertrophic cardiomyopathy, a primary disorder of the myocardium, is the most common cardiac disease in cats. However, determination of myocardial deformation with two-dimensional speckle-tracking echocardiography in cats with various stages of hypertrophic cardiomyopathy has not yet been reported. This study was designed to measure quantitatively multidirectional myocardial deformations of cats with hypertrophic cardiomyopathy. Methods Thirty-two client-owned cats with hypertrophic cardiomyopathy and 14 healthy cats serving as controls were enrolled and underwent assessment of myocardial deformation (peak systolic strain and strain rate) in the longitudinal, radial and circumferential directions. Results Longitudinal and radial deformations were reduced in cats with hypertrophic cardiomyopathy, despite normal systolic function determined by conventional echocardiography. Cats with severely symptomatic hypertrophic cardiomyopathy also had lower peak systolic circumferential strain, in addition to longitudinal and radial strain. Conclusions and relevance Longitudinal and radial deformation may be helpful in the diagnosis of hypertrophic cardiomyopathy. Additionally, the lower circumferential deformation in cats with severe hypertrophic cardiomyopathy may contribute to clinical findings of decompensation, and seems to be related to severe cardiac clinical signs. Indices of multidirectional myocardial deformations by two-dimensional speckle-tracking echocardiography may be useful markers and help to distinguish between cats with hypertrophic cardiomyopathy and healthy cats. Additionally, they may provide more detailed assessment of contractile function in cats with hypertrophic cardiomyopathy.

  5. Speckle tracking imaging improves in vivo assessment of EPO-induced myocardial salvage early after ischemia-reperfusion in rats.

    Science.gov (United States)

    Treguer, Frederic; Donal, Erwan; Tamareille, Sophie; Ghaboura, Nehmat; Derumeaux, Geneviève; Furber, Alain; Prunier, Fabrice

    2010-06-01

    A noninvasive assessment of infarct size and transmural extension of myocardial infarction (TEMI) is fundamental in experimental models of ischemia-reperfusion. Conventional echocardiography parameters are limited in this purpose. This study was designed to examine whether speckle tracking imaging can be used in a rat model of ischemia-reperfusion to accurately detect the reduction of infarct size and TEMI induced by erythropoietin (EPO) as early as 24 h after reperfusion. Rats were randomly assigned to one of three groups: myocardial infarction (MI)-control group, 45 min ischemia followed by 24 h of reperfusion; MI-EPO group, similar surgery with a single bolus of EPO administered at the onset of reperfusion; and sham-operated group. Short-axis two-dimensional echocardiography was performed after reperfusion. Global radial (GS(r)) and circumferential (GS(cir)) strains were compared with infarct size and TEMI assessed after triphenyltetrazolium chloride staining. As a result, ejection fraction, shortening fraction, GS(r), and GS(cir) significantly correlated to infarct size, whereas only GS(r) and GS(cir) significantly correlated to TEMI. EPO significantly decreased infarct size (30.8 + or - 3.5 vs. 56.2 + or - 5.7% in MI-control, P 0.75 24 h after reperfusion. In conclusion, these findings demonstrate the usefulness of speckle tracking imaging in the early evaluation of a cardioprotective strategy in a rat model of ischemia-reperfusion.

  6. Sources of variation in assessing left atrial functions by 2D speckle-tracking echocardiography.

    Science.gov (United States)

    Rimbaş, Roxana Cristina; Mihăilă, Sorina; Vinereanu, Dragoş

    2016-03-01

    Left atrial (LA) strain and strain rate, determined by speckle-tracking echocardiography (STE), are reproducible indices to assess LA function. Different normal ranges for LA phasic functions have been reported. We investigated the role of the reference point (P- and R-wave), gain, and region of interest (ROI), as the major sources of variation when assessing LA function. 52 subjects were evaluated for LA conventional and STE analysis. 45 of them (46 ± 14 years, 26 men) were feasible for concomitant LA deformation, and LA phasic volumes and ejection fractions (LAEF) evaluation. First, we compared the P- and R-wave methods, for the evaluation of the LA functions. We used diastolic mitral profile to clearly delineate the time intervals for each LA function. For the P-wave method, active function was assessed from negative global strain as a difference between the strain at pre-atrial contraction and strain just before mitral valve closure (GSA-), and late diastolic strain rate (GSRL); passive function from positive strain at MVO (GSA+), and from early negative diastolic strain rate (GSRE); reservoir function from the sum of GSA- and GSA+ (TGSA), and positive strain rate at the beginning of LV systole (GSR+). For the R-wave method we used the same SR parameters. The active function was evaluated by late positive global strain (GSAC), the reservoir by positive peak before the opening of the mitral valve (TGSA), and conduit function by the difference between TGSA and GSAC (GSA+). Then, by using P-wave method, we measured all previously described parameters for different gains-minimum (G0), medium (G12), and maximum (G24), and for different ROIs-minimum (ROI0), step 1 (ROI1), and 2 (ROI2). Feasibility of the LA strain measurements was 87 %. Active LA function was similar in the absolute value (GSAC and GSA-), whereas passive and reservoir functions were significantly higher (GSA+, TGSA) with the R-wave method. Active LAEF correlated with GSA- measured by the P-wave (r

  7. Second trimester ultrasound: reference values for two-dimensional speckle tracking-derived longitudinal strain, strain rate and time to peak deformation of the fetal heart

    NARCIS (Netherlands)

    Kapusta, L.; Mainzer, G.; Weiner, Z.; Deutsch, L.; Khoury, A.; Haddad, S.; Lorber, A.

    2012-01-01

    BACKGROUND: Data on myocardial deformation during the internationally widely used second-trimester screening are scarce and confusing. Reference values of time to peak strain are missing. The aims of this study were to assess reference values derived from two-dimensional speckle-tracking

  8. Persistent reduction in left ventricular strain using two-dimensional speckle-tracking echocardiography after balloon valvuloplasty in children with congenital valvular aortic stenosis.

    NARCIS (Netherlands)

    Marcus, K.A.; Korte, C.L. de; Feuth, T.; Thijssen, J.M.; Oort, A.M. van; Tanke, R.B.; Kapusta, L.

    2012-01-01

    BACKGROUND: The aim of this study was to investige serial changes of myocardial deformation using two-dimensional speckle-tracking echocardiographic (2DSTE) imaging in children undergoing balloon valvuloplasty for congenital valvular aortic stenosis (VAS). METHODS: Thirty-seven children with

  9. Valoración de la función del apéndice auricular izquierdo por speckle tracking

    Directory of Open Access Journals (Sweden)

    Jairo A. Rendón

    2014-06-01

    Full Text Available Objetivo: Caracterizar la función del apéndice auricular izquierdo por speckle tracking bidimensional, en pacientes en ritmo sinusal y en fibrilación auricular. Métodos: Se realizó ecocardiografía transesofágica para valorar la deformación longitudinal, la tasa de deformación longitudinal, las velocidades del tejido, el volumen y la fracción de eyección del apéndice auricular izquierdo a través de speckle tracking bidimensional, en pacientes en ritmo sinusal y con fibrilación auricular. Resultados: Se incluyeron 91 pacientes de quienes fue posible analizar 80 (88%. El 25% estaba en fibrilación auricular y de éstos el 9% tenía trombo en el apéndice auricular izquierdo; el 46% correspondía a hombres con edad media de 60 años (18-93. Se encontraron diferencias significativas entre los pacientes con fibrilación auricular vs. ritmo sinusal en la facción de eyección del apéndice auricular izquierdo (26,7% vs. 50,1%, las velocidades de vaciamiento por Doppler (28,5 vs. 55,6 cm/s, las velocidades tisulares (3,6 vs. 9,9 cm/s, la deformación longitudinal (5,7% vs. 17%, la tasa de deformación longitudinal (0,9 vs. 3,1 y los volúmenes mínimos del apéndice auricular izquierdo (6,3 vs. 3,0 mL. No se encontraron diferencias significativas entre los pacientes en fibrilación auricular con trombo o sin éste. Conclusión: La valoración de la función del apéndice auricular izquierdo por medio de speckle tracking, es una herramienta útil para caracterizar la función de esta estructura; su alteración se podría relacionar con el riesgo de desarrollar trombos y eventos embólicos secundarios.

  10. Super-resolution imaging applied to moving object tracking

    Science.gov (United States)

    Swalaganata, Galandaru; Ratna Sulistyaningrum, Dwi; Setiyono, Budi

    2017-10-01

    Moving object tracking in a video is a method used to detect and analyze changes that occur in an object that being observed. Visual quality and the precision of the tracked target are highly wished in modern tracking system. The fact that the tracked object does not always seem clear causes the tracking result less precise. The reasons are low quality video, system noise, small object, and other factors. In order to improve the precision of the tracked object especially for small object, we propose a two step solution that integrates a super-resolution technique into tracking approach. First step is super-resolution imaging applied into frame sequences. This step was done by cropping the frame in several frame or all of frame. Second step is tracking the result of super-resolution images. Super-resolution image is a technique to obtain high-resolution images from low-resolution images. In this research single frame super-resolution technique is proposed for tracking approach. Single frame super-resolution was a kind of super-resolution that it has the advantage of fast computation time. The method used for tracking is Camshift. The advantages of Camshift was simple calculation based on HSV color that use its histogram for some condition and color of the object varies. The computational complexity and large memory requirements required for the implementation of super-resolution and tracking were reduced and the precision of the tracked target was good. Experiment showed that integrate a super-resolution imaging into tracking technique can track the object precisely with various background, shape changes of the object, and in a good light conditions.

  11. Wall-motion tracking in fetal echocardiography-Influence of frame rate on longitudinal strain analysis assessed by two-dimensional speckle tracking.

    Science.gov (United States)

    Enzensberger, Christian; Achterberg, Friederike; Graupner, Oliver; Wolter, Aline; Herrmann, Johannes; Axt-Fliedner, Roland

    2017-06-01

    Frame rates (FR) used for strain analysis assessed by speckle tracking in fetal echocardiography show a considerable variation. The aim of this study was to investigate the influence of the FR on strain analysis in 2D speckle tracking. Fetal echocardiography was performed prospectively on a Toshiba Aplio 500 system and a Toshiba Artida system, respectively. Based on an apical or basal four-chamber view of the fetal heart, cine loops were stored with a FR of 30 fps (Aplio 500) and 60 fps (Artida/Aplio 500). For both groups (30fps and 60fps), global and segmental longitudinal peak systolic strain (LPSS) values of both, left (LV) and right ventricle (RV), were assessed by 2D wall-motion tracking. A total of 101 fetuses, distributed to three study groups, were included. The mean gestational age was 25.2±5.0 weeks. Mean global LPSS values for RV in the 30 fps group and in the 60 fps group were -16.07% and -16.47%, respectively. Mean global LPSS values for LV in the 30 fps group and in the 60 fps group were -17.54% and -17.06%, respectively. Comparing global and segmental LPSS values of both, the RV and LV, did not show any statistically significant differences within the two groups. Performance of myocardial 2D strain analysis by wall-motion tracking was feasible with 30 and 60 fps. Obtained global and segmental LPSS values of both ventricles were relatively independent from acquisition rate. © 2017, Wiley Periodicals, Inc.

  12. Left ventricular deformation by speckle tracking echocardiography at 2-year follow-up in treatment naive rheumatoid arthritis patients

    DEFF Research Database (Denmark)

    Logstrup, B. B.; Masic, D.; Laurberg, T. B.

    2015-01-01

    -CCP titers were evaluated by standardized techniques at baseline and 2-year follow-up. We performed a novel advanced echocardiography by speckle tracking in means of global LV systolic deformation (GLS) imaging. One experienced senior rheumatologist and one experienced cardiologist performed all the clinical...... joints (28): 8.4+/-3.6 and 1.08+/-0.5, CRP: 10.4+/-9 and 4.4+/-8.8 mmol/l, HAQ: 0.67+/-0.64 and 0.24+/-0.13, pain VAS: 54.7+/-13.5 and 20.2+/-17.5, fatigue VAS: 51.2+/-23.5 and 26.4+/-20.9, physician global assessment: 54.7+/-13.5 and 11.4+/-14.6 and finally DAS28-CRP: 4.8+/-0.8 and 2.1+/-1. At baseline...

  13. Normal left ventricular mechanics by two-dimensional speckle-tracking echocardiography. Reference values in healthy adults.

    Science.gov (United States)

    Kocabay, Gonenc; Muraru, Denisa; Peluso, Diletta; Cucchini, Umberto; Mihaila, Sorina; Padayattil-Jose, Seena; Gentian, Denas; Iliceto, Sabino; Vinereanu, Dragos; Badano, Luigi P

    2014-08-01

    Two-dimensional speckle-tracking echocardiography is a novel tool to assess myocardial function. The purpose of this study was to evaluate left ventricular myocardial strain and rotation parameters by two-dimensional speckle-tracking echocardiography in a large group of healthy adults across a wide age range to establish their reference values and to assess the influence of age, sex, and hemodynamic factors. Transthoracic echocardiograms were acquired in 247 healthy volunteers (139 women, 44 years [standard deviation, 16 years old] (range, 18-80 years). We measured longitudinal, circumferential, and radial peak systolic strain values, and left ventricular rotation and twist. Average values of global longitudinal, radial, and circumferential strain were -21.5% (standard deviation, 2.0%), 40.1% (standard deviation, 11.8%) and -22.2% (standard deviation, 3.4%), respectively. Longitudinal strain was significantly more negative in women, whereas radial and circumferential strain and rotational parameters were similar in both sexes. Accordingly, lower limits of normality for the strain components were -16.9% in men and -18.5% in women for longitudinal strain, and -15.4% for circumferential and 24.6% for radial strain, irrespective of sex. Longitudinal strain values were more negative at the base than at apical segments. Mean rotational values were -6.9° (standard deviation, 3.5°) for the base, 13.0° (standard deviation, 6.5°) for apical rotation, and 20.0° (standard deviation, 7.3°) for net twist. We report the comprehensive assessment of normal myocardial deformation and rotational mechanics in a large cohort of healthy volunteers. We found that women have more negative longitudinal strain, accounting for their higher left ventricular ejection fraction. Availability of reference values for these parameters may foster their implementation in the clinical routine. Copyright © 2013 Sociedad Española de Cardiología. Published by Elsevier Espana. All rights reserved.

  14. Optimal Analysis of Left Atrial Strain by Speckle Tracking Echocardiography: P-wave versus R-wave Trigger.

    Science.gov (United States)

    Hayashi, Shuji; Yamada, Hirotsugu; Bando, Mika; Saijo, Yoshihito; Nishio, Susumu; Hirata, Yukina; Klein, Allan L; Sata, Masataka

    2015-08-01

    Left atrial (LA) strain analysis using speckle tracking echocardiography is useful for assessing LA function. However, there is no established procedure for this method. Most investigators have determined the electrocardiographic R-wave peak as the starting point for LA strain analysis. To test our hypothesis that P-wave onset should be used as the starting point, we measured LA strain using 2 different starting points and compared the strain values with the corresponding LA volume indices obtained by three-dimensional (3D) echocardiography. We enrolled 78 subjects (61 ± 17 years, 25 males) with and without various cardiac diseases in this study and assessed global longitudinal LA strain by two-dimensional speckle tracking strain echocardiography using EchoPac software. We used either R-wave peak or P-wave onset as the starting point for determining LA strains during the reservoir (Rres, Pres), conduit (Rcon, Pcon), and booster pump (Rpump, Ppump) phases. We determined the maximum, minimum, and preatrial contraction LA volumes, and calculated the LA total, passive, and active emptying fractions using 3D echocardiography. The correlation between Pres and LA total emptying fraction was better than the correlation between Rres and LA total emptying fraction (r = 0.458 vs. 0.308, P = 0.026). Pcon and Ppump exhibited better correlation with the corresponding 3D echocardiographic parameters than Rcon (r = 0.560 vs. 0.479, P = 0.133) and Rpump (r = 0.577 vs. 0.345, P = 0.003), respectively. LA strain in any phase should be analyzed using P-wave onset as the starting point rather than R-wave peak. © 2014, Wiley Periodicals, Inc.

  15. Effects of frame rate on two-dimensional speckle tracking-derived measurements of myocardial deformation in premature infants.

    Science.gov (United States)

    Sanchez, Aura A; Levy, Philip T; Sekarski, Timothy J; Hamvas, Aaron; Holland, Mark R; Singh, Gautam K

    2015-05-01

    Frame rate (FR) of image acquisition is an important determinant of the reliability of 2-dimensional speckle tracking echocardiography (2DSTE)-derived myocardial strain. Premature infants have relatively high heart rates (HR). The aim was to analyze the effects of varying FR on the reproducibility of 2DSTE-derived right ventricle (RV) and left ventricle (LV) longitudinal strain (LS) and strain rate (LSR) in premature infants. RV and LV LS and LSR were measured by 2DSTE in the apical four-chamber view in 20 premature infants (26 ± 1 weeks) with HR 163 ± 13 bpm. For each subject, 4 sets of cine loops were acquired at FR of 130 frames/sec. Two observers measured LS and LSR. Inter- and intra-observer reproducibility was assessed using Bland-Altman analysis, coefficient of variation, and linear regression. Intra-observer reproducibility for RV and LV LS was higher at FR >110 frames/sec, and optimum at FR >130 frames/sec. The highest inter-observer reproducibility for RV and LV LS were at FR >130 and >110 frames/s, respectively. The highest reproducibility for RV and LV systolic and early diastolic LSR was at FR >110 frames/sec. FR/HR ratio >0.7 frames/sec per bpm yielded optimum reproducibility for RV and LV deformation imaging. The reliability of 2DSTE-derived RV and LV deformation imaging in premature infants is affected by the FR of image acquisition. Reproducibility is most robust when cine loops are obtained with FR/HR ratio between 0.7 and 0.9 frames/sec per bpm, which likely results from optimal myocardial speckle tracking and mechanical event timing. © 2014, Wiley Periodicals, Inc.

  16. Investigations of High Resolution Imaging through the Earth’s Atmosphere Using Speckle Interferometry.

    Science.gov (United States)

    1987-03-15

    personnel: Dr. Jeremy Hebden, Imaging Program Mr. Jonathan Freeman, Graduate Student: Imaging Program ’a Dr. Jack Drummond, Scientific Program...and proofs to: Jack Drummond Steward Observatory University of Arizona Tucson, Arizona 85721 4 2 177 Abstract The first glimpses of an asteroid’s...the Multiple Mirror Telescope as a Phased Array’ SPIE Proceedings 440, 1983. . 18. Nisenson, P., J. Apt, R. Goody , and C. Papaliolios, ’Speckle Imaging

  17. Real-time evaluation of longitudinal peak systolic strain (speckle tracking measurement in left and right ventricles of athletes

    Directory of Open Access Journals (Sweden)

    Stefani Laura

    2009-04-01

    Full Text Available Abstract Background Strain, and particularly Longitudinal Peak Systolic Strain (LPSS, plays a role in investigating the segmental and overall contractility of the heart which is a particularly interesting feature in athletes in whom regular training determines several morphological and functional modifications in both the ventricles, that normally work at different loads. Speckle tracking techniques assess the LPSS of LV and RV from B-mode imaging in real time, with uniform accuracy in all segments, and can verify the possible dissimilar segmental contributions of the two chambers to overall myocardial contraction. The aim of the study is to quantify the LPSS in real time in both the ventricles in order to estimate any possible different deformation properties in them during a systolic period. Methods 32 subjects (20 athletes and 18 controls were submitted to a standard echocardiographic examination at rest and after a Hand Grip (HG stress. From a four-chamber-view image, the LPSS parameter was measured with Speckle Tracking analysis in the basal and medium-apical segments of the two ventricles, at rest and after HG. Results In both athletes and controls, LPSS values were significantly higher in the RV of athletes (RV LPSS medium-apical -23.87 ± 4.94; basalfreewall -25.04 ± 4.12 at rest and controls (RV LPSSmedium-apical -25.21 ± 4.97; basalfreewall -28.69 ± 4.62 at rest than in the LV of both (athletes LV LPSS medium-apical -18.14 ± 4.16; basallateralwall -16.05 ± 12.32; controls medium-apical -18.81 ± 2.64; basallateralwall -19.74 ± 3.84 With the HG test a significant enhancement of the LPSS(with P Conclusion ST analysis is an easy method for investigating the contractility of the RV through deformation parameters, showing greater involvement of the RV than LV at rest. In athletes only, after isometric stress the two ventricles show particular myocardial deformation properties of the regions around the apex where the curvature of the

  18. Impact of pre-excitation syndrome on left ventricular systolic function and cardiac synchronization assessed by tissue Doppler imaging and speckle tracking techniques

    Directory of Open Access Journals (Sweden)

    Salah Atta

    2014-12-01

    Conclusion: Patients with pre-excitation syndrome may have depressed LV function unrelated to tachyarrhythmia, especially if the AP has a septal location. This dysfunction may be associated with the LV dyssynchronus contraction caused by pre-excitation. The use of TDI and speckle tracking echocardiographic techniques may be associated with an increase in the identification of manifest pre-excitation patients with significant LV dyssynchrony.

  19. Speckle-Tracking and Tissue-Doppler Stress Echocardiography in Arterial Hypertension: A Sensitive Tool for Detection of Subclinical LV Impairment

    OpenAIRE

    Hensel, Kai O.; Andreas Jenke; Roman Leischik

    2014-01-01

    Early diagnosis of cardiac alterations in hypertensive heart disease is still challenging. Since such patients might have depressed global LV systolic strain or strain rate when EF is still normal, speckle-tracking echocardiography (STE) and tissue-Doppler imaging (TDI) combined with stress echocardiography might improve early diagnosis of cardiac alterations. In this prospective study standard 2D Doppler echocardiography, STE, and TDI were performed at rest and during bicycle exercise in 92 ...

  20. Evaluation of myocardial viability in old myocardial infarcted patients with CHF: delayed enhancement MRI vs. low-dose dobutamine stress speckle tracking echocardiography.

    Science.gov (United States)

    Wang, Chaofan; Han, Shuguang; Xu, Tongda; Wang, Fengli; Wang, Xiaoping; Chen, Jing; Hu, Chunfeng; Li, Dongye

    2016-01-01

    The aim of this study was to explore the significance of delayed enhancement magnetic resonance imaging (DE-MRI) combined with two-dimensional speckle tracking echocardiography (STE) and low dose dobutamine stress echocardiography (LDDSE) to assess viable myocardium (VM) in the patients with old myocardial infarction (OMI) associated with congestive heart failure (CHF). Thirty five hospitalized OMI patients with regional wall motion abnormalities and left ventricular ejection fraction (LVEF) CHF.

  1. Investigations of High Resolution Imaging through the Earth’s Atmosphere Using Speckle Interferometry

    Science.gov (United States)

    1984-03-07

    disagree drastically, or agree well. But we can-n--o say whTiFhi thout Iurther analys. sT were observed under different conditions of solar illumination... st rting point of the analysis is the summed power spectra ( PS) of the individual 15ms epecklegrams. Each 2 PS -- of & Ori at a given wavelength was...Rho Persei and Alpha and 119 Tauri were carried out at the MMT on the night of 6 Dec 82 using the speckle spectrograph configuration described above

  2. Can ischemia and dyssynchrony be detected during early stages of dobutamine stress echocardiography by 2-dimensional speckle tracking echocardiography?

    Science.gov (United States)

    Yu, Yang; Villarraga, Hector R; Saleh, Haydar K; Cha, Stephen S; Pellikka, Patricia A

    2013-01-01

    Strain and strain rate (SR) measured with 2-dimensional speckle tracking echocardiography (2-D STE) can quantitatively assess myocardial function. Our aim was to evaluate whether we could detect abnormalities in strain, strain rate, and dyssynchrony by applying 2-D STE in patients with severe coronary artery disease during early stages of dobutamine stress echocardiography. Thirty-four patients with angiographically documented severe 3-vessel coronary artery disease and preserved left ventricular ejection fraction were compared with 42 control patients without evidence of coronary artery disease. Circumferential and longitudinal strain, SR, and left ventricular synchrony using standard deviation (SD) of time to systolic peak strain and SR were analyzed with 2-D STE at rest and at intermediate doses of dobutamine stress echocardiography. Compared with control subjects, patients with coronary artery disease showed lower circumferential SR [-1.42 (0.34) s(-1) vs -1.64 (0.34) s(-1); P strain [-15.41% (3.52%) vs -19.37% (3.21%); P intermediate doses; these values were also compromised at peak dose. The SD of longitudinal time to systolic peak strain at intermediate dose was significantly greater in patients with coronary artery disease than in control patients [37.89 (12.32) vs 27.21 (10.86); P strain and SR detected myocardial dysfunction and asynchrony in patients with coronary artery disease during intermediate doses of dobutamine stress, with minimal changes in regional wall motion abnormalities at this stage.

  3. Evaluation of right atrial function by two-dimensional speckle-tracking echocardiography in patients with right ventricular myocardial infarction.

    Science.gov (United States)

    Nourian, Saeed; Hosseinsabet, Ali; Jalali, Arash; Mohseni-Badalabadi, Reza

    2017-01-01

    Right ventricular myocardial infarction (RVMI) damages the systolic and diastolic functions of the RV, so the right atrium interacts with the RV with an acutely altered function. The aim of our study was to compare right atrial function as evaluated by 2D speckle-tracking echocardiography (2DSTE) between patients with inferior wall myocardial infarction (INFMI) and patients affected by both inferior myocardial infarction and right ventricular myocardial infarction (INFMI + RVMI). Our study recruited 70 consecutive patients with INFMI (43 patients without RVMI and 27 patients with RVMI). Right atrial function was evaluated by 2DSTE. Early diastolic strain, systolic strain rate, absolute value of early diastolic strain rate, expansion index, and diastolic emptying index of the right atrium were reduced in the patients with INFMI + RVMI compared to the patients with INFMI. The area under the curve for early diastolic strain for INFMI diagnosis was 0.682 (p value = 0.011, 95 % CI 0.550-0.815). Right atrial early diastolic longitudinal strain right atrial reservoir and conduit functions were impaired in the patients with INFMI + RVMI compared with the patients with INFMI.

  4. Right atrial myocardial deformation by two-dimensional speckle tracking echocardiography predicts recurrence in paroxysmal atrial fibrillation.

    Science.gov (United States)

    Govindan, Malini; Kiotsekoglou, Anatoli; Saha, Samir K; Camm, A John

    2017-12-01

    Atrial fibrillation (AF) is a bi-atrial disease yet little attention has been given to right heart function in AF. We propose that the assessment of right atrial (RA) and right ventricular function (RV) using two-dimensional speckle tracking echocardiography (2D-STE) could be valuable in predicting AF recurrence in patients with paroxysmal AF (PAF). Thirty patients with PAF were prospectively recruited from a dedicated AF clinic. Right atrial size, volume, and area and RV dimensions were analyzed along with RA and RV strain derived from 2D-STE at baseline and at 3 and 12 months. Higher RA booster strain independently predicted sinus rhythm (SR) maintenance for up to 1 year (P = 0.001). RV strain was impaired in patients with recurrent AF compared to those in SR (P right heart function in AF patients. RA booster strain function was predictive of sinus rhythm maintenance for up to 1 year.

  5. Assessment of left ventricular regional function in affected and carrier dogs with duchenne muscular dystrophy using speckle tracking echocardiography

    Directory of Open Access Journals (Sweden)

    Yugeta Naoko

    2011-05-01

    Full Text Available Abstract Background Two-dimensional speckle tracking echocardiography (STE is a relatively new method to detect regional myocardial dysfunction. To assess left ventricular (LV regional myocardial dysfunction using STE in Duchenne muscular dystrophy model dogs (CXMDJ without overt clinical signs of heart failure. Methods Six affected dogs, 8 carrier dogs with CXMDJ, and 8 control dogs were used. Conventional echocardiography, systolic and diastolic function by Doppler echocardiography, tissue Doppler imaging (TDI, and strain indices using STE, were assessed and compared among the 3 groups. Results Significant differences were seen in body weight, transmitral E wave and E' wave derived from TDI among the 3 groups. Although no significant difference was observed in any global strain indices, in segmental analysis, the peak radial strain rate during early diastole in posterior segment at chordae the tendineae level showed significant differences among the 3 groups. Conclusions The myocardial strain rate by STE served to detect the impaired cardiac diastolic function in CXMDJ without any obvious LV dilation or clinical signs. The radial strain rate may be a useful parameter to detect early myocardial impairment in CXMDJ.

  6. Influence of Positive End-Expiratory Pressure on Myocardial Strain Assessed by Speckle Tracking Echocardiography in Mechanically Ventilated Patients

    Directory of Open Access Journals (Sweden)

    Federico Franchi

    2013-01-01

    Full Text Available Purpose. The effects of mechanical ventilation (MV on speckle tracking echocardiography- (STE-derived variables are not elucidated. The aim of the study was to evaluate the effects of positive end-expiratory pressure (PEEP ventilation on 4-chamber longitudinal strain (LS analysis by STE. Methods. We studied 20 patients admitted to a mixed intensive care unit who required intubation for MV and PEEP titration due to hypoxia. STE was performed at three times: (T1 PEEP = 5 cmH2O; (T2 PEEP = 10 cmH2O; and (T3 PEEP = 15 cmH2O. STE analysis was performed offline using a dedicated software (XStrain MyLab 70 Xvision, Esaote. Results. Left peak atrial-longitudinal strain (LS was significantly reduced from T1 to T2 and from T2 to T3 (. Right peak atrial-LS and right ventricular-LS showed a significant reduction only at T3 (. Left ventricular-LS did not change significantly during titration of PEEP. Cardiac chambers’ volumes showed a significant reduction at higher levels of PEEP (. Conclusions. We demonstrated for the first time that incremental PEEP affects myocardial strain values obtained with STE in intubated critically ill patients. Whenever performing STE in mechanically ventilated patients, care must be taken when PEEP is higher than 10 cmH2O to avoid misinterpreting data and making erroneous decisions.

  7. Robust microbubble tracking for super resolution imaging in ultrasound

    DEFF Research Database (Denmark)

    Hansen, Kristoffer B.; Villagómez Hoyos, Carlos Armando; Brasen, Jens Christian

    2016-01-01

    Currently ultrasound resolution is limited by diffraction to approximately half the wavelength of the sound wave employed. In recent years, super resolution imaging techniques have overcome the diffraction limit through the localization and tracking of a sparse set of microbubbles through the vas...

  8. The influence of frame rate on two-dimensional speckle-tracking strain measurements: a study on silico-simulated models and images recorded in patients.

    Science.gov (United States)

    Rösner, Assami; Barbosa, Daniel; Aarsæther, Erling; Kjønås, Didrik; Schirmer, Henrik; D'hooge, Jan

    2015-10-01

    Ultrasound-derived myocardial strain can render valuable diagnostic and prognostic information. However, acquisition settings can have an important impact on the measurements. Frame rate (i.e. temporal resolution) seems to be of particular importance. The aim of this study was to find the optimal range of frame rates needed for most accurate and reproducible 2D strain measurements using a 2D speckle-tracking software package. Synthetic two dimensional (2D) ultrasound grey-scale images of the left ventricle (LV) were generated in which the strain in longitudinal, circumferential, and radial direction were precisely known from the underlying kinematic LV model. Four different models were generated at frame rates between 20 and 110 Hz. The resulting images were repeatedly analysed. Results of the synthetic data were validated in 66 patients, where long- and short-axis recordings at different frame rates were analysed. In simulated data, accurate strain estimates could be achieved at >30 frames per cycle (FpC) for longitudinal and circumferential strains. Lower FpC underestimated strain systematically. Radial strain estimates were less accurate and less reproducible. Patient strain displayed the same plateaus as in the synthetic models. Higher noise and the presence of artefacts in patient data were followed by higher measurement variability. Standard machine settings with a FR of 50-60 Hz allow correct assessment of peak global longitudinal and circumferential strain. Correct definition of the region of interest within the myocardium as well as the reduction of noise and artefacts seem to be of highest importance for accurate 2D strain estimation. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.

  9. Quantification of global myocardial function by cine MRI deformable registration-based analysis: Comparison with MR feature tracking and speckle-tracking echocardiography

    Energy Technology Data Exchange (ETDEWEB)

    Lamacie, Mariana M. [University Health Network, Department of Medical Imaging, Toronto, Ontario (Canada); Thavendiranathan, Paaladinesh [University Health Network, Department of Medical Imaging, Toronto, Ontario (Canada); University of Toronto, Department of Medicine, Division of Cardiology, Toronto, Ontario (Canada); Hanneman, Kate [University Health Network, Department of Medical Imaging, Toronto, Ontario (Canada); University of Toronto, Department of Medical Imaging, Toronto, Ontario (Canada); Greiser, Andreas [Siemens Healthcare, Erlangen (Germany); Jolly, Marie-Pierre [Medical Imaging Technologies, Siemens Healthcare, Princeton, NJ (United States); Ward, Richard [University of Toronto, Department of Medicine, Division of Cardiology, Toronto, Ontario (Canada); Wintersperger, Bernd J. [University Health Network, Department of Medical Imaging, Toronto, Ontario (Canada); University of Toronto, Department of Medical Imaging, Toronto, Ontario (Canada); Toronto General Hospital, Department of Medical Imaging, Toronto, Ontario (Canada)

    2017-04-15

    To evaluate deformable registration algorithms (DRA)-based quantification of cine steady-state free-precession (SSFP) for myocardial strain assessment in comparison with feature-tracking (FT) and speckle-tracking echocardiography (STE). Data sets of 28 patients/10 volunteers, undergoing same-day 1.5T cardiac MRI and echocardiography were included. LV global longitudinal (GLS), circumferential (GCS) and radial (GRS) peak systolic strain were assessed on cine SSFP data using commercially available FT algorithms and prototype DRA-based algorithms. STE was applied as standard of reference for accuracy, precision and intra-/interobserver reproducibility testing. DRA showed narrower limits of agreement compared to STE for GLS (-4.0 [-0.9,-7.9]) and GCS (-5.1 [1.1,-11.2]) than FT (3.2 [11.2,-4.9]; 3.8 [13.9,-6.3], respectively). While both DRA and FT demonstrated significant differences to STE for GLS and GCS (all p<0.001), only DRA correlated significantly to STE for GLS (r=0.47; p=0.006). However, good correlation was demonstrated between MR techniques (GLS:r=0.74; GCS:r=0.80; GRS:r=0.45, all p<0.05). Comparing DRA with FT, intra-/interobserver coefficient of variance was lower (1.6 %/3.2 % vs. 6.4 %/5.7 %) and intraclass-correlation coefficient was higher. DRA GCS and GRS data presented zero variability for repeated observations. DRA is an automated method that allows myocardial deformation assessment with superior reproducibility compared to FT. (orig.)

  10. 2D speckle tracking echocardiography of the right ventricle free wall in SCUBA divers after single open sea dive.

    Science.gov (United States)

    Susilovic-Grabovac, Zora; Obad, Ante; Duplančić, Darko; Banić, Ivana; Brusoni, Denise; Agostoni, Piergiuseppe; Vuković, Ivica; Dujic, Zeljko; Bakovic, Darija

    2018-03-01

    The presence of circulating gas bubbles and their influence on pulmonary and right heart hemodynamics was reported after uncomplicated self-contained underwater breathing apparatus (SCUBA) dive(s). Improvements in cardiac imaging have recently focused great attention on the right ventricle (RV). The aim of our study was to evaluate possible effects of a single air SCUBA dive on RV function using 2D speckle tracking echocardiography in healthy divers after single open sea dive to 18 meters of seawater, followed by bottom stay of 47 minutes with a direct ascent to the surface. Twelve experienced male divers (age 39.5 ± 10.5 years) participated in the study. Echocardiographic assessment of the right ventricular function (free wall 2 D strain, tricuspid annular planes systolic excursion [TAPSE], lateral tricuspid annular peak systolic velocity [RV s`] and fractional area change [FAC]) was performed directly prior to and 30, 60, 90 and 120 minutes after surfacing. Two-dimensional strain of all three segments of free right ventricular wall showed a significant increase in longitudinal shortening in post-dive period for maximally 26% (basal), 15.4% (mid) and 16.3% (apical) as well as TAPSE (11.6%), RV FAC (19.2%), RV S` (12.7%) suggesting a rise in systolic function of right heart. Mean pulmonary arterial pressure (mean PAP) increased post-dive from 13.3 mmHg to maximally 23.5 mmHg (P = .002), indicating increased RV afterload. Our results demonstrated that single dive with significant bubble load lead to increase in systolic function and longitudinal strain of the right heart in parallel with increase in mean PAP. © 2017 John Wiley & Sons Australia, Ltd.

  11. 2D longitudinal LV speckle tracking strain pattern in breast cancer survivors: sports activity vs exercise as prescription model.

    Science.gov (United States)

    Galanti, Giorgio; Pedrizzetti, Gianni; Pedri, Stefano; Stefani, Laura

    2017-12-01

    Prevention strategies are important to optimize and to manage heart care in breast cancer survivors. Regular physical activity at moderate intensity is normally proposed to maintain myocardial performance; however, no data is available about the different impact of different levels of physical exercise. 2D speckle tracking echocardiography (2DSTE) is an accepted method for early detection of myocardial dysfunction. The study aims to monitor the cardiac performances in breast cancer survivors by 2DSTE analysis to manage sports activity vs physical activity. Two groups of previous breast cancer survivors (33 BCS) trained at moderate intensity and 55 athletes practicing dragon boat (DBA) sport were enrolled. They were matched with two healthy subjects groups: 23 competitive female athletes practicing different sports and 20 healthy women trained with exercise as prescription model. All women were studied by a complete echo examination including LV global longitudinal strain (GLS) assessment (XStrain-Esaote). EF and GS are only significantly higher in healthy subjects (-25.4 ± 2.1). Nevertheless, GLS values are within the normal range for all groups. Particularly, GS does not show any significant differences among subjects (-19.93 ± 4) practicing exercise as prescription when compared to the DBA competitive trained group. 2DSTE method is an appropriate method to supervise the intensity of exercise in breast cancer patients. Particularly, GLS can optimize and improve cancer therapy supporting and creating efficiencies within the health system confirming the role of the exercise prescription therapy in maintaining normal heart function.

  12. Left Ventricular Myocardial Deformation Parameters Are Affected by Coronary Slow Flow Phenomenon: A Study of Speckle Tracking Echocardiography.

    Science.gov (United States)

    Gulel, Okan; Akcay, Murat; Soylu, Korhan; Aksan, Gokhan; Yuksel, Serkan; Zengin, Halit; Meric, Murat; Sahin, Mahmut

    2016-05-01

    The coronary slow flow phenomenon (CSFP) is defined as a delayed distal vessel contrast opacification in the absence of obstructive epicardial coronary artery disease during coronary angiography. There is conflicting data in medical literature regarding the effects of CSFP on the left ventricular functions assessed by conventional echocardiography or tissue Doppler imaging. Therefore, we aimed to evaluate whether there is any abnormality in the myocardial deformation parameters (strain, strain rate (SR), rotation, twist) of the left ventricle obtained by speckle tracking echocardiography (STE) in patients with CSFP. Twenty patients with CSFP were included prospectively in the study. Another 20 patients with similar demographics and cardiovascular risk factors as well as normal coronary angiography were used as the control group. Two-dimensional echocardiographic images of the left ventricle from the apical long-axis, two-chamber, four-chamber, and parasternal short-axis views were used for STE analysis. The analysis of left ventricular circumferential deformation parameters showed that the averaged peak systolic strain, systolic SR, and early diastolic SR values were significantly lower in patients with CSFP (P = 0.009, P = 0.02, and P = 0.02, respectively). Among the left ventricular rotation and twist values, apical rotation was significantly lower in patients with CSFP (P = 0.02). Further, the mean thrombolysis in myocardial infarction frame count value was found to be negatively correlated with the averaged peak circumferential early diastolic SR (r = -0.35, P = 0.03). It was positively correlated with the averaged peak circumferential systolic strain (r = 0.47, P = 0.003) and circumferential systolic SR (r = 0.46, P = 0.005). Coronary slow flow phenomenon leads to significant alterations in the myocardial deformation parameters of the left ventricle as assessed by STE. Specifically, circumferential deformation parameters are affected in CSFP patients. © 2015

  13. [Left ventricular longitudinal rotation changes in patients with dilated cardiomyopathy detected by two-dimensional speckle tracking imaging].

    Science.gov (United States)

    Huang, Jun; Ni, Xian-da; Hu, Yuan-ping; Song, Zhang-wei; Yang, Wei-yu; Xu, Rui

    2011-10-01

    To assess the left ventricular longitudinal rotation (LR) in patients with dilated cardiomyopathy (DCM). Conventional echocardiography (GE-Vivid7) was performed in 35 healthy subjects and 42 DCM patients. Left atrial diameter was measured by M-mode echocardiography, left ventricular end-systolic, end-diastolic volume and left ventricular ejection fraction (LVEF) were calculated by bi-plane simpson's method. The peak velocity during early diastole (Ve) and late diastole (Va) of anterior mitral valve were measured by pulse-waved doppler, and the ratio Ve/Va was calculated. The peak radial systolic strain, strain rate in systolic, early and late diastolic periods were measured. Segmental LR and global LR were assessed using two-dimensional speckle tracking imaging (2D-STI). The peak radial systolic strain, strain rate in systolic, early and late diastolic periods in DCM group were significantly lower than in healthy subjects, the rotation degrees of the middle and base lateral, the apex and the base septum walls were significantly lower than those of the healthy subjects. A prominent counterclockwise LR (0.76° ± 2.63°) was shown in healthy subjects while prominent clockwise LR (-1.58° ± 3.42°) was present in DCM patients. The time delay between the left ventricular lateral wall and the base septum wall in DCM patients significantly correlated with the peak LR of the left ventricular (r = 0.409, P DCM patients and a clockwise LR is present in DCM patients which might be caused by the time delay between the left ventricular lateral wall and the base-septum wall.

  14. Supernormal functional reserve of apical segments in elite soccer players: an ultrasound speckle tracking handgrip stress study

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    Cappelli Brunello

    2008-04-01

    Full Text Available Abstract Background Ultrasound speckle tracking from grey scale images allows the assessment of regional strain derived from 2D regardless of angle intonation, and it is highly reproducible. The study aimed to evaluate regional left ventricular functional reserve in elite soccer players. Methods 50 subjects (25 elite athletes and 25 sedentary controls, aged 26 ± 3.5, were submitted to an echo exam, at rest and after the Hand Grip (HG test. Both standard echo parameters and strain were evaluated. Results Ejection fraction was similar in athletes and controls both at rest (athletes 58 ± 2 vs controls 57 ± 4 p ns and after HG (athletes 60 ± 2 vs controls 58 ± 3 p ns. Basal (septal and anterior segments showed similar strain values in athletes and controls both at rest (athletes S% -19.9 ± 4.2; controls S% -18.8 ± 4.9 p = ns and after HG (athletes S% -20.99 ± 2.8; controls S% -19.46 ± 4.4 p = ns. Medium-apical segments showed similar strain values at rest (athletes S% -17.31 ± 2.3; controls S% -20.00 ± 5.3 p = ns, but higher values in athletes after HG (athletes S% -24.47 ± 2.8; controls S% -20.47 ± 5.4 p Conclusion In athletes with physiological myocardial hypertrophy, a brief isometric effort produces enhancement of the strain in medium-apical left ventricular segments, suggesting the presence of a higher regional function reserve which can be elicited with an inotropic challenge and suitable methods of radial function quantification such as 2D-derived strain.

  15. Left ventricular myocardial performance assessed by 2-dimensional speckle tracking echocardiography in patients with sickle cell crisis.

    Science.gov (United States)

    Sengupta, Shantanu P; Jaju, Rahul; Nugurwar, Abhijeet; Caracciolo, Giuseppe; Sengupta, Partho P

    2012-01-01

    The status of left ventricle in sickle cell anemia presenting in sickle crisis and follow up has been minimally studied in past. To determine the left ventricular (LV) myocardial performance in these patients, we performed the study to assess two dimensional strains imaging which allowed a rapid and an accurate analysis of global and regional LV myocardial performance in longitudinal, radial, and circumferential directions. In this prospective study, 2-dimensional echocardiography (2DE) images of the LV were obtained in 52 subjects which included 32 patients (23 ± 8yrs, 16 male) with homozygous sickle cell anemia (SCA) in sickle cell crisis and 20 healthy controls (23 ± 5 yrs, 11 male) using apical 4-chamber and parasternal short-axis at the basal, mid, and apical levels. Of these 32 patients, 2DE was performed again in 18 patients in follow up (8 months ± 5 days). Longitudinal, circumferential and radial strains (LS, CS and RS respectively) were quantified and compared in an 18-segment model using a novel speckle tracking system (2D Cardiac Performance Analysis, TomTec Imaging System, Munich, Germany). There was no significant difference in LV ejection fraction between both the groups (59.32 ± 12.6 vs. 52.3 ± 7.9; p-value > 0.05). In comparison with normal controls and follow up of sickle cell patients, peak LS was significantly attenuated in the subendocardial and subepicardial regions during sickle cell crisis (p crisis showed significantly higher radial strain parameters than controls (p crisis have reduced longitudinal shortening. LV myocardial performance remains unaltered due to relatively preserved circumferential shortening and increased radial thickening. Copyright © 2012 Cardiological Society of India. Published by Elsevier B.V. All rights reserved.

  16. Left Atrial Systolic and Diastolic Dysfunction in Patients with Chronic Constrictive Pericarditis: A Study Using Speckle Tracking and Conventional Echocardiography.

    Directory of Open Access Journals (Sweden)

    Shuang Liu

    Full Text Available Left atrial (LA function plays an important role in the maintenance of cardiac output, however, in patients with constrictive pericarditis (CP, whether pericardial restriction and adhesion can lead to LA dysfunction, and the characteristics of LA function remain unclear. The aim of the study is to compare the left atrial (LA function of patients with CP to that of healthy study participants using speckle tracking echocardiography (STE and conventional echocardiography.Thirty patients with CP and 30 healthy volunteers (controls were enrolled in the study. The underlying cause of CP was viral pericarditis in 24 (80% patients and unknown in 6 (20% patients. The LA maximum volume (Vmax, LA minimal volume (Vmin, and LA volume before atrial contraction (Vpre-a were measured using biplane modified Simpson's method. The LA expansion index (LA reservoir function was determined as follows: ([LAVmax - LAVmin]/LAVmin ×100. The passive emptying index (LA conduit function was calculated as follows: ([LAVmax - LAVpre-a]/LAVmax ×100, and the active emptying index (booster pump function was calculated as follows: ([LAVpre-a - LAVmin]/LAVpre-a ×100. All the patients underwent two-dimensional STE. The LA global systolic strain (S, systolic strain rate (SrS, early diastolic strain rate (SrE and late diastolic strain rate (SrA were measured. The LA expansion index, passive emptying index, the active emptying index and the LA global S, SrS, SrE, SrA were found to be significantly lower in patients with CP than in the control participants (P <0.001. LA function was correlated with the early diastolic velocity of the lateral mitral annulus (P <0.05.Although left ventricular systolic function was preserved in patients with CP, the LA reservoir, conduit, and booster functions were impaired. Pericardial restriction and impairment of the LA myocardium may play an important role in the reduction of LA function in patients with CP.

  17. High-Frame-Rate Deformation Imaging in Two Dimensions Using Continuous Speckle-Feature Tracking.

    Science.gov (United States)

    Andersen, Martin V; Moore, Cooper; Arges, Kristine; Søgaard, Peter; Østergaard, Lasse R; Schmidt, Samuel E; Kisslo, Joseph; Von Ramm, Olaf T

    2016-11-01

    The study describes a novel algorithm for deriving myocardial strain from an entire cardiac cycle using high-frame-rate ultrasound images. Validation of the tracking algorithm was conducted in vitro prior to the application to patient images. High-frame-rate ultrasound images were acquired in vivo from 10 patients, and strain curves were derived in six myocardial regions around the left ventricle from the apical four-chamber view. Strain curves derived from high-frame-rate images had a higher frequency content than those derived using conventional methods, reflecting improved temporal sampling. Copyright © 2016 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  18. Two-Dimensional Speckle-Tracking during Dobutamine Stress Echocardiography in the Detection of Myocardial Ischemia in Patients with Suspected Coronary Artery Disease.

    Science.gov (United States)

    Uusitalo, Valtteri; Luotolahti, Matti; Pietilä, Mikko; Wendelin-Saarenhovi, Maria; Hartiala, Jaakko; Saraste, Markku; Knuuti, Juhani; Saraste, Antti

    2016-05-01

    Two-dimensional speckle-tracking applied to dobutamine stress echocardiography (DSE) may aid in the detection of coronary artery disease (CAD). The aim of this study was to determine the value of strain, strain rate, and postsystolic strain index (PSI) measured by speckle-tracking during DSE in the evaluation of the presence, extent, and severity of myocardial ischemia. Fifty patients 63 ± 7 years of age with intermediate probability of CAD were prospectively recruited. All patients underwent DSE, quantitative positron emission tomographic perfusion imaging, and invasive angiography. Regional peak systolic longitudinal strain, strain rate, and PSI were measured at rest, at a dobutamine dose of 20 μg/kg/min, at peak stress, and at early recovery (1 min after stress). Obstructive CAD was defined as >75% stenosis or 40% to 75% stenosis combined with either fractional flow reserve Strain analyses showed the highest reproducibility at rest, at a dobutamine dose of 20 μg/kg/min, and at early recovery. Increased PSI and reduced strain during early recovery were the strongest predictors of obstructive CAD and were associated with the extent, localization, and depth of myocardial ischemia by positron emission tomography. On vessel-based analysis, strain, PSI, and visual analysis of wall motion provided comparable diagnostic accuracy, whereas the combination of strain or PSI with visual analysis provided incremental value over visual analysis alone. Assessment of systolic or postsystolic strain by speckle-tracking echocardiography during early recovery after DSE can help in the detection of hemodynamically significant coronary stenosis compared with visual wall motion analysis alone. Copyright © 2016 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.

  19. Two-dimensional right ventricular strain by speckle tracking for assessment of longitudinal right ventricular function after paediatric congenital heart disease surgery.

    Science.gov (United States)

    Karsenty, Clement; Hadeed, Khaled; Dulac, Yves; Semet, Florent; Alacoque, Xavier; Breinig, Sophie; Leobon, Bertrand; Acar, Philippe; Hascoet, Sebastien

    2017-03-01

    Right ventricular (RV) function is a prognostic marker of cardiac disease in children. Speckle tracking has been developed to assess RV longitudinal shortening, the dominant deformation during systole; little is known about its feasibility in children with congenital heart disease (CHD). To evaluate the feasibility and reproducibility of RV two-dimensional (2D) strain assessed by speckle tracking in infants undergoing CHD surgery compared with conventional markers. In this prospective single-centre study, RV peak systolic strain (RV-PSS) was measured using 2D speckle tracking in 37 consecutive children undergoing CHD surgery. Examinations were performed the day before surgery, a few hours after surgery and before discharge. Relationships with the z score of tricuspid annular plane systolic excursion (TAPSE) and tricuspid annular systolic velocity (TA Sa) were assessed. Median (interquartile range) age was 19 months (5-63); median weight was 9.2 kg (5.3-18.0). RV-PSS analysis was feasible in 92.9% (95% confidence interval [CI]: 86.0-97.1) of examinations. The coefficient of variation was 9.7% (95% CI: 7.4-11.9) for intraobserver variability and 15.1% (95% CI: 12.7-17.6) for interobserver variability. Correlations between RV-PSS and z score of TAPSE and TA Sa were strong (r=0.71, P<0.0001 and r=0.70, P<0.0001, respectively). RV-PSS was significantly reduced after surgery compared with baseline (-10.5±2.9% vs. -19.5±4.8%; P<0.0001) and at discharge (-13.5±4.0% vs. -19.5±4.8%; P<0.0001). Similar evolutions were observed with TAPSE and TA Sa (both P<0.0001). RV longitudinal strain by speckle tracking is a feasible and reproducible method of assessing perioperative evolution of RV function in children with CHD. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  20. Application of Speckle-Tracking Echocardiography in an Experimental Model of Isolated Subendocardial Damage.

    Science.gov (United States)

    Beyhoff, Niklas; Brix, Sarah; Betz, Iris R; Klopfleisch, Robert; Foryst-Ludwig, Anna; Krannich, Alexander; Stawowy, Philipp; Knebel, Fabian; Grune, Jana; Kintscher, Ulrich

    2017-10-21

    The subendocardium is highly vulnerable to damage and is thus affected even in subclinical disease stages. Therefore, methods reflecting subendocardial status are of great clinical relevance for the early detection of cardiac damage and the prevention of functional impairment. The aim of this study was to investigate the potential ability of myocardial strain parameters to evaluate changes within the subendocardium. Male 129/Sv mice were injected with isoproterenol (ISO; n = 32) to induce isolated subendocardial fibrotic lesions or saline as appropriate control (n = 15). Transthoracic echocardiography was performed using a 30-MHz linear-frequency transducer coupled to a high-resolution imaging system, and acquired images were analyzed for conventional and strain parameters. The degree of collagen content within the different cardiac layers was quantified by histologic analysis and serum levels of tissue inhibitor of metalloproteinase-1, a biomarker for fibrosis, were assessed. ISO treatment induced a marked increase in subendocardial collagen content in response to cell loss (control vs ISO, 0.6 ± 0.3% vs 5.8 ± 0.9%; P subendocardial collagen content (r = 0.46, P = .01) and tissue inhibitor of metalloproteinase-1 serum level (r = 0.52, P subendocardial fibrosis (sensitivity, 84%; specificity, 80%; cutoff value, -14.4%). Assessment of LS may provide a noninvasive method for the detection of subendocardial damage and may consequently improve early diagnosis of cardiac diseases. Copyright © 2017 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.

  1. What Limits an Altimeter's Resolution of Along-Track Geoid Slope? Insights from Saral and Cryosat

    Science.gov (United States)

    Smith, W. H. F.

    2014-12-01

    Satellite altimeter data collected along densely spaced ground tracks can map the marine gravity field, revealing the tectonic fabric of the sea floor. This application requires high accuracy of the along-track derivative of sea surface height over distances shorter than 80 km, and so is very sensitive to the instrument's range precision and any factors that produce short-scale along-track correlation of range measurement errors. To date the altimeters that have collected data over a dense network of ground tracks all acquired their largest data sets in Ku band and employing conventional (incoherent) processing. Two new altimeters go beyond conventional Ku instruments. SARAL AltiKa operates as an incoherent altimeter at Ka-band, and CryoSat collects some Ku-band data in a SAR mode to permit coherent processing for aperture synthesis and delay-Doppler calculations. The along-track range noise correlation characteristics of each of these new measurements are different from what has been seen in previous altimeters. SARAL AltiKa has a lower noise floor than pre-Cryosat Ku-band instruments and its noise spectrum shows decorrelation at different wavelengths, in partial agreement with theoretical work on speckle noise decorrelation over homogeneous surfaces. This improved noise performance results in demonstrable improvement in the resolution of geoid anomalies over small seamounts. Retracking of Cryosat's SAR mode multi-looked waveform yields a decorrelation of range errors unlike that found in conventional instruments, such that it doesn't require two-pass retracking to get the best geoid slope resolution. This is due mainly to the waveform's shape, which yields partial derivatives with respect to geophysical parameter estimates that are more nearly orthogonal than in conventional Ku-band Brown model waveforms. Further understanding of the limits on range precision in these instruments will require understanding of the heterogeneities in reflecting surfaces that are

  2. Right ventricular free-wall longitudinal speckle tracking strain in patients with pulmonary arterial hypertension under specific treatment.

    Science.gov (United States)

    Kemal, Hatice S; Kayikcioglu, Meral; Kultursay, Hakan; Vuran, Ozcan; Nalbantgil, Sanem; Mogulkoc, Nesrin; Can, Levent

    2017-04-01

    Right ventricular (RV) dysfunction is a major determinant of outcomes in patients with pulmonary arterial hypertension (PAH), although the optimal measure of RV function is poorly defined. We evaluated the utility of RV free-wall speckle tracking strain as an assessment tool for RV function in patients with PAH who are already under specific treatment compared with conventional echocardiographic parameters and investigated the relationship of RV free-wall strain with clinical hemodynamic parameters of RV performance. Right ventricular free-wall strain was evaluated in 92 patients (Group-1 and Group-4 pulmonary hypertension) who were on PAH-specific treatment for at least 3 months. Right atrial (RA) area, RV FAC, TAPSE, tricuspid S, functional class, 6-minute walking distance, and NT-proBNP were studied. The mean duration of follow-up was 222±133 days. All patients were under PAH-specific treatment, and mean RV free-wall strain was -13.16±6.3%. RV free-wall strain correlated well with functional class (r=.312, P=.01), NT-proBNP (r=.423, P=.0001), RA area (r=.427, P=.0001), FAC (r=-.637, P=.0001), TAPSE (r=-.524, P=.0001), tricuspid S (r=-.450, P=.0001), 6-minute walking distance (r=-.333, P=.002). RV free-wall strain significantly correlated with all follow-up adverse events, death, and clinical right heart failure (RHF) (P=.04, P=.03, P=.02, respectively). According to the receiver operator characteristic analysis, the cutoff value for RV free-wall strain for the development of clinical RHF was -12.5% (sensitivity: 71%, specificity: 67%) and for all cardiovascular adverse events (death included) was -12.5% (sensitivity: 54%, specificity: 64%). Assessment of RV free-wall strain is a feasible, easy-to-perform method and may be used as a predictor of RHF, clinical deterioration, and mortality in patients already under PAH-specific treatment. © 2017, Wiley Periodicals, Inc.

  3. Evaluation of myocardial deformation in patients with Kawasaki disease using speckle-tracking echocardiography during mid-term follow-up.

    Science.gov (United States)

    Dedeoglu, Reyhan; Barut, Kenan; Oztunc, Funda; Atik, Sezen; Adrovic, Amra; Sahin, Sezgin; Cengiz, Dicle; Kasapcopur, Ozgur

    2017-09-01

    Speckle-tracking echocardiography is a recently developed technique for the evaluation of myocardial deformation or strain. Our objective was to examine strain through a mid-term follow-up of patients with Kawasaki disease. We explored left ventricular mechanics using speckle-tracking echocardiography in 35 patients with a history of Kawasaki disease at least 6 months after the acute phase. We also included 30 healthy children as controls. Strain data sets were acquired for the quantification of left ventricular global strain, segmental strain, and left ventricular ejection fraction. The mean age of our patients was 25.6±15.4 months. At a median follow-up of 57.5 months (16.5-98.2), although both values were in the normal range, the mean left ventricular ejection proportion of patients (57.3%) was a little lower than that of controls (p⩽0.05). Patient strain values at the basal inferoseptal (20.0), basal anterolateral (19.5), apical septal (23.3), and apical inferior (24.0) segments were lower compared with controls. In all, seven patients had coronary aneurysms during follow-up. Kawasaki disease patients with pyuria had lower left ventricular strain at the mid anterior, mid anteroseptal, apical anterior, and apical inferior segments and global longitudinal strain compared with patients with no pyuria (p⩽0.05). In children with a history of Kawasaki disease, impairment of left ventricular mechanics occurs especially within the left anterior descending artery territories.

  4. Development of left ventricular longitudinal speckle tracking echocardiography in very low birth weight infants with and without bronchopulmonary dysplasia during the neonatal period.

    Directory of Open Access Journals (Sweden)

    Christoph Czernik

    Full Text Available OBJECTIVES: In preterm infants, postnatal myocardial adaptation may be complicated by bronchopulmonary dysplasia (BPD. We aimed to describe the development of left ventricular function by serial 2D, Doppler, and speckle tracking echocardiography (2D-STE in infants with and without BPD during the neonatal period and compare these to anthropometric and conventional hemodynamic parameters. STUDY DESIGN: Prospective echocardiography on day of life (DOL 1, 7, 14, and 28 in 119 preterm infants 10% were seen for the apical segment. While anthropometric parameters show rapid development during the first 4 weeks of life, the speckle tracking parameters did not differ statistically significantly during the neonatal period. Infants with and without BPD differed significantly (p<0.001 in the development of anthropometric parameters, conventional hemodynamic parameters except for heart rate, and 2D-STE parameters: global longitudinal systolic strain rate (GLSSR and longitudinal systolic strain for the mid left wall (LSSR. The largest differences were seen at DOL 1 and 7 in GLSSR (p<0.001 and in LSSR (p<0.01. CONCLUSIONS: Reproducible 2D-STE measurements are possible in preterm infants <1500 g. Cardiac deformation reveals early (DOL 1 and 7 ventricular changes (GLSSR and LSSR in very low birth weight infants who develop BPD.

  5. Repeatability and reproducibility of measurements obtained via two-dimensional speckle tracking echocardiography of the left atrium and time-left atrial area curve analysis in healthy dogs.

    Science.gov (United States)

    Osuga, Tatsuyuki; Nakamura, Kensuke; Lim, Sue Yee; Tamura, Yu; Kumara, Wickramasekara Rajapakshage Bandula; Murakami, Masahiro; Sasaki, Noboru; Morishita, Keitaro; Ohta, Hiroshi; Yamasaki, Masahiro; Takiguchi, Mitsuyoshi

    2013-06-01

    To evaluate left atrial phasic function in healthy dogs by means of 2-D speckle tracking echocardiography with time-left atrial area curve analysis and to assess repeatability and reproducibility of obtained measurements. 6 healthy Beagles. Each dog underwent echocardiography twice on different days (3 nonconsecutive examinations/d). Images were analyzed with offline software; area of the left atrium was automatically calculated in each frame throughout the cardiac cycle to derive time-left atrial area curves. Variables used to assess left atrial phasic function (total, passive, and active emptying area and emptying fractions and mean active and total emptying rates) were calculated. Agreement between variables measured via speckle tracking echocardiography and a manual tracing method was assessed with modified Bland-Altman analysis. Within-day and between-day coefficients of variation were determined. Mean ± SD total, passive, and active emptying fractions of the left atrium were 49.8 ± 3.5%, 277 ± 4.0%, and 30.5 ± 4.3%, respectively. Mean ± SD total and active emptying rates were 16.0 ± 2.5 cm(2)/s and 25.1 ± 4.9 cm(2)/s, respectively. Within-day and between-day coefficients of variation were canine patients.

  6. Left Ventricular Speckle Tracking-Derived Cardiac Strain and Cardiac Twist Mechanics in Athletes: A Systematic Review and Meta-Analysis of Controlled Studies.

    Science.gov (United States)

    Beaumont, Alexander; Grace, Fergal; Richards, Joanna; Hough, John; Oxborough, David; Sculthorpe, Nicholas

    2017-06-01

    The athlete's heart is associated with physiological remodeling as a consequence of repetitive cardiac loading. The effect of exercise training on left ventricular (LV) cardiac strain and twist mechanics are equivocal, and no meta-analysis has been conducted to date. The objective of this systematic review and meta-analysis was to review the literature pertaining to the effect of different forms of athletic training on cardiac strain and twist mechanics and determine the influence of traditional and contemporary sporting classifications on cardiac strain and twist mechanics. We searched PubMed/MEDLINE, Web of Science, and ScienceDirect for controlled studies of aged-matched male participants aged 18-45 years that used two-dimensional (2D) speckle tracking with a defined athlete sporting discipline and a control group not engaged in training programs. Data were extracted independently by two reviewers. Random-effects meta-analyses, subgroup analyses, and meta-regressions were conducted. Our review included 13 studies with 945 participants (controls n = 355; athletes n = 590). Meta-analyses showed no athlete-control differences in LV strain or twist mechanics. However, moderator analyses showed greater LV twist in high-static low-dynamic athletes (d = -0.76, 95% confidence interval [CI] -1.32 to -0.20; p mechanics between athletes and healthy controls. Differences in speckle tracking echocardiography-derived parameters can be identified using suitable sporting categorizations.

  7. Estimation of reactogenicity of preparations produced on the basis of photoinactivated live vaccines against brucellosis and tularaemia on the organismic level.2. Using the method of speckle-microscopy with high spatial resolution

    Science.gov (United States)

    Ulianova, O. V.; Uianov, S. S.; Li, Pengcheng; Luo, Qingming

    2011-04-01

    The method of speckle microscopy was adapted to estimate the reactogenicity of the prototypes of vaccine preparations against extremely dangerous infections. The theory is proposed to describe the mechanism of formation of the output signal from the super-high spatial resolution speckle microscope. The experimental studies show that bacterial suspensions, irradiated in different regimes of inactivation, do not exert negative influence on the blood microcirculations in laboratory animals.

  8. High Resolution Order Tracking at Extreme Slew Rates Using Kalman Tracking Filters

    Directory of Open Access Journals (Sweden)

    Håvard Vold

    1995-01-01

    Full Text Available The analysis of the periodic components in noise and vibration signals measured on rotating equipment such as car power trains, must be done more and more under rapid changes of an axle, or reference RPM. Normal tracking filters (analog or digital implementations have limited resolution in such situations; wavelet methods, even when applied after resampling the data to be proportional to an axle RPM, must compromise between time and frequency resolution. The authors propose the application of nonstationary Kalman filters for the tracking of periodic components in such noise and vibration signals. These filters are designed to accurately track signals with a known structure among noise and signal components of different, “unknown,” structure. The tracking characteristics of these filters, i.e., the predicted signal amplitude versus time values versus exact signal amplitude versus time values, can be tailored to accurate tracking of harmonics buried in other signal components and noise, even at high rates of change of the reference RPM. A key to the successful construction is the precise knowledge of the structure of the signal to be tracked. For signals that vary with an axle RPM, an accurate estimate of the instantaneous RPM is essential, and procedures to this end will also be presented.

  9. Usefulness of left ventricular speckle tracking echocardiography and novel measures of left atrial structure and function in diagnosing paroxysmal atrial fibrillation in ischemic stroke and transient ischemic attack patients

    DEFF Research Database (Denmark)

    Skaarup, Kristoffer Grundtvig; Christensen, Hanne; Host, Nis

    2017-01-01

    Asymptomatic paroxysmal atrial fibrillation (PAF) is often assumed to be the cause of cryptogenic ischemic strokes (IS) and transient ischemic attacks (TIA). We examined the usefulness of measures obtained by 2D speckle tracking echocardiography and novel left atrial measurements, in the diagnosis...

  10. Adaptive optics with pupil tracking for high resolution retinal imaging.

    Science.gov (United States)

    Sahin, Betul; Lamory, Barbara; Levecq, Xavier; Harms, Fabrice; Dainty, Chris

    2012-02-01

    Adaptive optics, when integrated into retinal imaging systems, compensates for rapidly changing ocular aberrations in real time and results in improved high resolution images that reveal the photoreceptor mosaic. Imaging the retina at high resolution has numerous potential medical applications, and yet for the development of commercial products that can be used in the clinic, the complexity and high cost of the present research systems have to be addressed. We present a new method to control the deformable mirror in real time based on pupil tracking measurements which uses the default camera for the alignment of the eye in the retinal imaging system and requires no extra cost or hardware. We also present the first experiments done with a compact adaptive optics flood illumination fundus camera where it was possible to compensate for the higher order aberrations of a moving model eye and in vivo in real time based on pupil tracking measurements, without the real time contribution of a wavefront sensor. As an outcome of this research, we showed that pupil tracking can be effectively used as a low cost and practical adaptive optics tool for high resolution retinal imaging because eye movements constitute an important part of the ocular wavefront dynamics.

  11. Alterations in multidirectional myocardial functions in patients with aortic stenosis and preserved ejection fraction: a two-dimensional speckle tracking analysis.

    Science.gov (United States)

    Ng, Arnold C T; Delgado, Victoria; Bertini, Matteo; Antoni, Marie Louisa; van Bommel, Rutger J; van Rijnsoever, Eva P M; van der Kley, Frank; Ewe, See Hooi; Witkowski, Tomasz; Auger, Dominique; Nucifora, Gaetano; Schuijf, Joanne D; Poldermans, Don; Leung, Dominic Y; Schalij, Martin J; Bax, Jeroen J

    2011-06-01

    To identify changes in multidirectional strain and strain rate (SR) in patients with aortic stenosis (AS). A total of 420 patients (age 66.1 ± 14.5 years, 60.7% men) with aortic sclerosis, mild, moderate, and severe AS with preserved left ventricular (LV) ejection fraction [(EF), ≥50%] were included. Multidirectional strain and SR imaging were performed by two-dimensional speckle tracking. Patients were more likely to be older (P multiple linear regressions. Patients with AS have evidence of subclinical myocardial dysfunction early in the disease process despite normal LVEF. The myocardial dysfunction appeared to start in the subendocardium and progressed to transmural dysfunction with increasing AS severity. Symptomatic moderate and severe AS patients had more impaired multidirectional myocardial functions compared with asymptomatic patients.

  12. Detection of Left Atrium Myopathy Using Two-Dimensional Speckle Tracking Echocardiography in Patients with End-Stage Renal Disease on Dialysis Therapy.

    Science.gov (United States)

    Hassanin, Noha; Alkemary, Alkhateeb

    2016-02-01

    Left atrium (LA) deformation analysis by two-dimensional speckle tracking echocardiography (2DSTE) has recently been proposed to evaluate left ventricular (LV) filling pressure in dialysis patients. The purpose of this study was to study the LA function in dialysis patients using two-dimensional speckle tracking echocardiography correlated to prevalence of atrial fibrillation, echocardiographically pulmonary capillary wedge pressure, and right ventricle systolic pressure. Hundred adult patients aged 49.3 ± 13.9 years on regular hemodialysis and 40 healthy individuals were enrolled in the study. Left ventricular dimensions, ejection fraction, and mass index were studied. Left atrium volume index (LAVI) was calculated by dividing left atrium volumes by body surface area. Left ventricle filling pressure was evaluated according to E/E'. Left atrium global systolic strain (LASS) was studied using 2DSTE. Left atrium stiffness was calculated noninvasively based on the ratio of E/E' to LASS. Right ventricle systolic pressure was estimated with the Bernoulli equation formula. Left atrium diameter, left ventricle indexed mass, mitral (E/E'), and LA stiffness were increased in dialysis group 4.4 ± 0.2 cm, 126.5 ± 24.6 g/m(2) , 16.9 ± 4.4, and 0.5 ± 0.1, respectively, P dialysis patients (26.6 ± 1.9 vs. 33.7 ± 2.1%, P dialysis patients with atrial fibrillation (AF) compared to those without AF. Assessment of LA deformation parameters predicts LV diastolic dysfunction and right ventricle systolic pressure in dialysis patients. Left atrium function in dialysis patients was impaired before the occurrence of left atrium dilatation. © 2015, Wiley Periodicals, Inc.

  13. Assessment of atrial fibrillation and vulnerability in patients with Wolff-Parkinson-White syndrome using two-dimensional speckle tracking echocardiography.

    Directory of Open Access Journals (Sweden)

    Jing-Jie Li

    Full Text Available PURPOSE: The aim was to assess atrial fibrillation (AF and vulnerability in Wolff-Parkinson-White (WPW syndrome patients using two-dimensional speckle tracking echocardiography (2D-STE. METHODS: All patients were examined via transthoracic echocardiography and 2D-STE in order to assess atrial function 7 days before and 10 days after RF catheter ablation. A postoperative 3-month follow-up was performed via outpatient visit or telephone calls. RESULTS: Results showed significant differences in both body mass index (BMI and supraventricular tachycardia (SVT duration between WPW patients and DAVNP patients (both P<0.05. Echocardiography revealed that the maximum left atrial volume (LAVmax and the left ventricular mass index (LVMI in diastole increased noticeably in patients with WPW compared to patients with DAVNP both before and after ablation (all P<0.05. Before ablation, there were obvious differences in the levels of SRs, SRe, and SRa from the 4-chamber view (LA in the WPW patients group compared with patients in the DAVNP group (all P<0.05. In the AF group, there were significant differences in the levels of systolic strain rate (SRs, early diastolic strain rate (SRe, and late diastolic strain rate (SRa from the 4-chamber view (LA both before and after ablation (all P<0.05. In the non-AF group, there were decreased SRe levels from the 4-chamber view (LA/RA pre-ablation compared to post-ablation (all P<0.05. CONCLUSION: Our findings provide convincing evidence that WPW syndrome may result in increased atrial vulnerability and contribute to the development of AF. Further, RF catheter ablation of AAV pathway can potentially improve atrial function in WPW syndrome patients. Two-dimensional speckle tracking echocardiography imaging in WPW patients would be necessary in the evaluation and improvement of the overall function of RF catheter ablation in a long-term follow-up period.

  14. Right Ventricular Systolic Dysfunction in Chagas Disease Defined by Speckle-Tracking Echocardiography: A Comparative Study with Cardiac Magnetic Resonance Imaging.

    Science.gov (United States)

    Moreira, Henrique T; Volpe, Gustavo J; Marin-Neto, José A; Nwabuo, Chike C; Ambale-Venkatesh, Bharath; Gali, Luis G; Almeida-Filho, Oswaldo C; Romano, Minna M D; Pazin-Filho, Antonio; Maciel, Benedito C; Lima, João A C; Schmidt, André

    2017-05-01

    Chagas disease leads to biventricular heart failure, usually with prominent systemic congestion. Although echocardiography is widely used in clinical routine, the utility of echocardiographic parameters to detect right ventricular (RV) systolic dysfunction in patients with Chagas disease is unknown. We sought to study the diagnostic value of echocardiography, including speckle-tracking parameters, to distinguish individuals with RV systolic dysfunction from those with normal RV systolic function in Chagas disease using cardiac magnetic resonance (CMR) as the reference method. In this cross-sectional study, 63 individuals with Chagas disease underwent echocardiography and CMR evaluations. Conventional echocardiographic parameters for RV functional evaluation were tricuspid annular plane systolic excursion, RV systolic excursion velocity, fractional area change, and RV index of myocardial performance. Strain and strain rate were obtained by two-dimensional speckle-tracking echocardiography and defined as "RV free wall," when based only in segments from RV free wall, or "RV free wall and septum," when segments from both free RV wall and interventricular septum were included. RV systolic dysfunction was defined as RV ejection fraction (RVEF) -22.5% for men and >-23.3% for women) exhibited the highest area under the receiver operating characteristic curve (area under the curve = 0.829) to differentiate the presence from the absence of RV systolic dysfunction in Chagas disease, with a sensitivity and specificity of 67% and 83%, respectively. RV free wall strain is an appropriate and superior echocardiographic variable for evaluating RV systolic function in Chagas disease, and it should be the method of choice for this purpose. Copyright © 2017 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.

  15. Clinical feasibility and validation of 3D principal strain analysis from cine MRI: comparison to 2D strain by MRI and 3D speckle tracking echocardiography.

    Science.gov (United States)

    Satriano, Alessandro; Heydari, Bobak; Narous, Mariam; Exner, Derek V; Mikami, Yoko; Attwood, Monica M; Tyberg, John V; Lydell, Carmen P; Howarth, Andrew G; Fine, Nowell M; White, James A

    2017-12-01

    Two-dimensional (2D) strain analysis is constrained by geometry-dependent reference directions of deformation (i.e. radial, circumferential, and longitudinal) following the assumption of cylindrical chamber architecture. Three-dimensional (3D) principal strain analysis may overcome such limitations by referencing intrinsic (i.e. principal) directions of deformation. This study aimed to demonstrate clinical feasibility of 3D principal strain analysis from routine 2D cine MRI with validation to strain from 2D tagged cine analysis and 3D speckle tracking echocardiography. Thirty-one patients undergoing cardiac MRI were studied. 3D strain was measured from routine, multi-planar 2D cine SSFP images using custom software designed to apply 4D deformation fields to 3D cardiac models to derive principal strain. Comparisons of strain estimates versus those by 2D tagged cine, 2D non-tagged cine (feature tracking), and 3D speckle tracking echocardiography (STE) were performed. Mean age was 51 ± 14 (36% female). Mean LV ejection fraction was 66 ± 10% (range 37-80%). 3D principal strain analysis was feasible in all subjects and showed high inter- and intra-observer reproducibility (ICC range 0.83-0.97 and 0.83-0.98, respectively-p cine estimates of longitudinal (r = 0.81 and r = -0.81), circumferential (r = 0.87 and r = -0.85), and radial (r = -0.76 and r = 0.81) strain (p cine (feature tracking) estimates of longitudinal (r = 0.85 and -0.83), circumferential (r = 0.88 and r = -0.87), and radial strain (r = -0.79 and r = 0.84, p cine MRI and shows high reproducibility with strong correlations to 2D conventional strain analysis and 3D STE-based analysis. Given its independence from geometry-related directions of deformation this technique may offer unique benefit for the detection and prognostication of myocardial disease, and warrants expanded investigation.

  16. OCT Amplitude and Speckle Statistics of Discrete Random Media

    NARCIS (Netherlands)

    Almasian, Mitra; van Leeuwen, Ton G.; Faber, Dirk J.

    2017-01-01

    Speckle, amplitude fluctuations in optical coherence tomography (OCT) images, contains information on sub-resolution structural properties of the imaged sample. Speckle statistics could therefore be utilized in the characterization of biological tissues. However, a rigorous theoretical framework

  17. Left ventricular 2D flow pattern estimation by combining speckle tracking with Navier-Stokes-based regularization in an iterative way

    Science.gov (United States)

    Gao, Hang; Kremer, Florence; Choi, Hon Fai; Voigt, Jens-Uwe; Claus, Piet; D'hooge, Jan

    2011-03-01

    Ultrasound imaging with low dose contrast injection would be of interest to better characterize the cardiac flow dynamics inside the left ventricle (LV). The aim of this study was to combine speckle tracking (ST) with regularization based on Navier-Stokes (NS) equations in an iterative manner in order to improve the pure ST results when the inflow velocities were high. It was tested in a Computational Fluid Dynamics (CFD) based Ultrasound simulation environment. On two subsequent images in diastasis, block-matching was applied using normalized cross-correlation as a similarity measure and spline-interpolation for subsample motion estimation. During regularization, the difference between the measured and the regularized velocity field was added as an external force to a finite difference implementation of the NS equations. This regularized velocity field was used as prior to the ST procedure between the following pair of images by guiding and reshaping the search region appropriately. This iterative approach was performed in the forward and the backward temporal direction to obtain the flow fields of the whole filling phase. The RMSE of all velocity estimates (amplitude & angle) within each frame was calculated using the CFD velocity vector fields as the ground truth and these findings were contrasted to pure ST. In this study, we could thus show that LV flow tracking by combining ST with NS based regularization in an iterative manner improves the accuracy of the pure ST results even at high inflow velocity.

  18. Ocular microtremor laser speckle metrology

    Science.gov (United States)

    Al-Kalbani, M.; Mihaylova, E.; Collins, N.; Toal, V.; Coakley, D.; Boyle, G.

    2009-02-01

    Ocular Microtremor (OMT) is a continual, high frequency physiological tremor of the eye present in all subjects even when the eye is apparently at rest. OMT causes a peak to peak displacement of around 150nm-2500nm with a broadband frequency spectrum between 30Hz to 120Hz; with a peak at about 83Hz. OMT carries useful clinical information on depth of consciousness and on some neurological disorders. Nearly all quantitative clinical investigations have been based on OMT measurements using an eye contacting piezoelectric probe which has low clinical acceptability. Laser speckle metrology is a candidate for a high resolution, non-contacting, compact, portable OMT measurement technique. However, tear flow and biospeckle might be expected to interfere with the displacement information carried by the speckle. The paper investigates the properties of the scattered speckle of laser light (λ = 632.8nm) from the eye sclera to assess the feasibility of using speckle techniques to measure OMT such as the speckle correlation. The investigation is carried using a high speed CMOS video camera adequate to capture the high frequency of the tremor. The investigation is supported by studies using an eye movement simulator (a bovine sclera driven by piezoelectric bimorphs). The speckle contrast and the frame to frame spatiotemporal variations are analyzed to determine if the OMT characteristics are detectable within speckle changes induced by the biospeckle or other movements.

  19. Speckle Imaging Over Horizontal Paths

    Energy Technology Data Exchange (ETDEWEB)

    Carrano, C J

    2002-05-21

    Atmospheric aberrations reduce the resolution and contrast in surveillance images recorded over horizontal or slant paths. This paper describes our recent horizontal and slant path imaging experiments of extended scenes as well as the results obtained using speckle imaging. The experiments were performed with an 8-inch diameter telescope placed on either a rooftop or hillside and cover ranges of interest from 0.5 km up to 10 km. The scenery includes resolution targets, people, vehicles, and other structures. The improvement in image quality using speckle imaging is dramatic in many cases, and depends significantly upon the atmospheric conditions. We quantify resolution improvement through modulation transfer function measurement comparisons.

  20. High-resolution eye tracking using V1 neuron activity

    Science.gov (United States)

    McFarland, James M.; Bondy, Adrian G.; Cumming, Bruce G.; Butts, Daniel A.

    2014-01-01

    Studies of high-acuity visual cortical processing have been limited by the inability to track eye position with sufficient accuracy to precisely reconstruct the visual stimulus on the retina. As a result, studies on primary visual cortex (V1) have been performed almost entirely on neurons outside the high-resolution central portion of the visual field (the fovea). Here we describe a procedure for inferring eye position using multi-electrode array recordings from V1 coupled with nonlinear stimulus processing models. We show that this method can be used to infer eye position with one arc-minute accuracy – significantly better than conventional techniques. This allows for analysis of foveal stimulus processing, and provides a means to correct for eye-movement induced biases present even outside the fovea. This method could thus reveal critical insights into the role of eye movements in cortical coding, as well as their contribution to measures of cortical variability. PMID:25197783

  1. High-resolution tracking in a GEM-emulsion detector

    Science.gov (United States)

    Alexandrov, A.; Bencivenni, G.; Bertani, M.; Buonaura, A.; Capoccia, C.; Cibinetto, G.; De Lellis, G.; De Lucia, E.; Di Crescenzo, A.; Domenici, D.; Farinelli, R.; Felici, G.; Kitagawa, N.; Komatsu, M.; Morello, G.; Morishima, K.; Poli Lener, M.; Tioukov, V.

    2017-09-01

    SHiP (Search for Hidden Particles) is a beam dump experiment proposed at the CERN SPS aiming at the observation of long-lived particles very weakly coupled with ordinary matter mostly produced in the decay of charmed hadrons. The beam dump facility of SHiP is also a copious factory of neutrinos of all three kinds and therefore a dedicated neutrino detector is foreseen in the SHiP apparatus. The neutrino detector exploits the Emulsion Cloud Chamber technique with a modular structure, alternating walls of target units and planes of electronic detectors providing the time stamp to the event. GEM detectors are one of the possible choices for this task. This paper reports the results of the first exposure to a muon beam at CERN of a new hybrid chamber, obtained by coupling a GEM chamber and an emulsion detector. Thanks to a position accuracy of the emulsion detector of the order of the micrometer, the position resolution of the GEM chamber as a function of the particle inclination was evaluated in two configurations, with and without the magnetic field. It ranges from a minimum of 54 μm for normal incident tracks up to (320±40) μm for incoming tracks with θ = 45o and magnetic field strength of 1 T.

  2. Which shoulder motions cause subacromial impingement? Evaluating the vertical displacement and peak strain of the coracoacromial ligament by ultrasound speckle tracking imaging.

    Science.gov (United States)

    Park, In; Lee, Hyo-Jin; Kim, Sung-Eun; Bae, Sung-Ho; Byun, Chu-Hwan; Kim, Yang-Soo

    2015-11-01

    Subacromial impingement is a common cause of shoulder pain and one cause of rotator cuff disease. We aimed to identify which shoulder motions cause subacromial impingement by measuring the vertical displacement and peak strain of the coracoacromial ligament using ultrasound speckle tracking imaging. Sixteen shoulders without shoulder disability were enrolled. All subjects were men, and the average age was 28.6 years. The vertical displacement and peak strain of the coracoacromial ligament were analyzed by the motion tracing program during the following active assisted motions (active motion controlled by the examiner): (1) forward flexion in the scapular plane, (2) horizontal abduction in the axial plane, (3) external rotation with the arm at 0° abduction (ER0), (4) internal rotation with the arm at 0° abduction (IR0), (5) internal rotation with the arm at 90° abduction (IR90), and (6) internal rotation at the back (IRB). The mean vertical displacement of the coracoacromial ligament during forward flexion (2.2 mm), horizontal abduction (2.2 mm), and IR90 (2.4 mm) was significantly greater than that during the other motions (ER0, -0.7 mm; IR0, 0.5 mm; IRB, 1.0 mm; P impingement. It is recommended that patients with impingement syndrome or a repaired rotator cuff avoid these shoulder motions. Copyright © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  3. Speckle-Tracking and Tissue-Doppler Stress Echocardiography in Arterial Hypertension: A Sensitive Tool for Detection of Subclinical LV Impairment

    Directory of Open Access Journals (Sweden)

    Kai O. Hensel

    2014-01-01

    Full Text Available Early diagnosis of cardiac alterations in hypertensive heart disease is still challenging. Since such patients might have depressed global LV systolic strain or strain rate when EF is still normal, speckle-tracking echocardiography (STE and tissue-Doppler imaging (TDI combined with stress echocardiography might improve early diagnosis of cardiac alterations. In this prospective study standard 2D Doppler echocardiography, STE, and TDI were performed at rest and during bicycle exercise in 92 consecutive patients—46 hypertensive subjects with normal ejection fraction and 46 healthy controls. STE and TDI were used to measure global peak systolic LV circumferential strain (CS, longitudinal strain (LS, and longitudinal strain rate (SR. Mean arterial blood pressure was significantly higher in hypertensive patients at rest (100.8 mmHg SD 13.5 mmHg; P=0.002 and during physical exercise testing (124.2 mmHg SD 13.4 mmHg; P=0.003. Hypertensive patients had significantly reduced values of systolic CS (P=0.001, LS (P=0.014, and SR (P<0.001 at rest as well as during physical exercise—CS (P<0.001, LS (P<0.001, and SR (P<0.001. Using STE and TDI, reduced LV systolic strain and strain rate consistent with early cardiac alterations can be detected in patients with arterial hypertension. These findings were evident at rest and markedly pronounced during exercise echocardiography.

  4. Subclinical Alterations of Cardiac Mechanics Present Early in the Course of Pediatric Type 1 Diabetes Mellitus: A Prospective Blinded Speckle Tracking Stress Echocardiography Study

    Directory of Open Access Journals (Sweden)

    Kai O. Hensel

    2016-01-01

    Full Text Available Diabetic cardiomyopathy substantially accounts for mortality in diabetes mellitus. The pathophysiological mechanism underlying diabetes-associated nonischemic heart failure is poorly understood and clinical data on myocardial mechanics in early stages of diabetes are lacking. In this study we utilize speckle tracking echocardiography combined with physical stress testing in order to evaluate whether left ventricular (LV myocardial performance is altered early in the course of uncomplicated type 1 diabetes mellitus (T1DM. 40 consecutive asymptomatic normotensive children and adolescents with T1DM (mean age 11.5±3.1 years and mean disease duration 4.3±3.5 years and 44 age- and gender-matched healthy controls were assessed using conventional and quantitative echocardiography (strain and strain rate during bicycle ergometer stress testing. Strikingly, T1DM patients had increased LV longitudinal (p=0.019 and circumferential (p=0.016 strain rate both at rest and during exercise (p=0.021. This was more pronounced in T1DM patients with a longer disease duration (p=0.038. T1DM patients with serum HbA1c>9% showed impaired longitudinal (p=0.008 and circumferential strain (p=0.005 and a reduced E/A-ratio (p=0.018. In conclusion, asymptomatic T1DM patients have signs of hyperdynamic LV contractility early in the course of the disease. Moreover, poor glycemic control is associated with early subclinical LV systolic and diastolic impairment.

  5. Subclinical Alterations of Cardiac Mechanics Present Early in the Course of Pediatric Type 1 Diabetes Mellitus: A Prospective Blinded Speckle Tracking Stress Echocardiography Study

    Science.gov (United States)

    Hensel, Kai O.; Grimmer, Franziska; Roskopf, Markus; Jenke, Andreas C.; Wirth, Stefan; Heusch, Andreas

    2016-01-01

    Diabetic cardiomyopathy substantially accounts for mortality in diabetes mellitus. The pathophysiological mechanism underlying diabetes-associated nonischemic heart failure is poorly understood and clinical data on myocardial mechanics in early stages of diabetes are lacking. In this study we utilize speckle tracking echocardiography combined with physical stress testing in order to evaluate whether left ventricular (LV) myocardial performance is altered early in the course of uncomplicated type 1 diabetes mellitus (T1DM). 40 consecutive asymptomatic normotensive children and adolescents with T1DM (mean age 11.5 ± 3.1 years and mean disease duration 4.3 ± 3.5 years) and 44 age- and gender-matched healthy controls were assessed using conventional and quantitative echocardiography (strain and strain rate) during bicycle ergometer stress testing. Strikingly, T1DM patients had increased LV longitudinal (p = 0.019) and circumferential (p = 0.016) strain rate both at rest and during exercise (p = 0.021). This was more pronounced in T1DM patients with a longer disease duration (p = 0.038). T1DM patients with serum HbA1c > 9% showed impaired longitudinal (p = 0.008) and circumferential strain (p = 0.005) and a reduced E/A-ratio (p = 0.018). In conclusion, asymptomatic T1DM patients have signs of hyperdynamic LV contractility early in the course of the disease. Moreover, poor glycemic control is associated with early subclinical LV systolic and diastolic impairment. PMID:26839891

  6. Acute Effects of an Energy Drink on Myocardial Function Assessed by Conventional Echo-Doppler Analysis and by Speckle Tracking Echocardiography on Young Healthy Subjects

    Directory of Open Access Journals (Sweden)

    Daniele Menci

    2013-01-01

    Full Text Available Purpose. Previous studies have underlined the effects of the energy drinks containing caffeine end taurine on the cardiovascular system. The aim of this study was to determine acute changes on echocardiographic parameters assessed by conventional echo-Doppler analysis and by speckle tracking echocardiography after the consumption of an energy drink in a young healthy population. Methods. measurement of blood pressure, electrocardiographic, and echocardiographic examination were performed on 35 healthy subjects (mean age 25 ± 2 years, 16 men, at baseline and one hour after the consumption of a body surface area indexed amount of an energy drink (168 mL/m2 containing caffeine (0.03% and taurine (0.4%. Results. The analysis of left ventricular function showed a significant increase of mean relative values of MAPSE (+11%; , global longitudinal strain (+10%, , and left ventricular twisting (+22%, in respect to baseline. Also, right ventricular function parameters appeared significantly increased after energy drink consumption, as TAPSE (+15%, , global, and free wall right ventricular longitudinal strain (+8%, ; +5%, , resp.. Conclusion. In conclusion, the consumption of the ED in our population showed a significant increase of right and left ventricular myocardial function, suggesting a possible positive inotropic effect related to the substances contained therein.

  7. Persistent reduction in left ventricular strain using two-dimensional speckle-tracking echocardiography after balloon valvuloplasty in children with congenital valvular aortic stenosis.

    Science.gov (United States)

    Marcus, Karen A; de Korte, Chris L; Feuth, Ton; Thijssen, Johan M; van Oort, Anton M; Tanke, Ronald B; Kapusta, Livia

    2012-05-01

    The aim of this study was to investige serial changes of myocardial deformation using two-dimensional speckle-tracking echocardiographic (2DSTE) imaging in children undergoing balloon valvuloplasty for congenital valvular aortic stenosis (VAS). Thirty-seven children with isolated congenital VAS were enrolled in this study prospectively. Patients underwent echocardiographic evaluation at three instances: before balloon valvuloplasty, 6 months after intervention, and 3 years after intervention. Longitudinal, circumferential, and radial peak systolic strain values were determined, as well as systolic strain rate and the time to peak global systolic strain. Linear mixed statistical models were used to assess changes in 2DSTE parameters after balloon intervention. Using one-way analysis of variance, 2DSTE results at 3-year follow-up were compared with 2DSTE measurements in 74 healthy age-matched children and 76 children with uncorrected VAS whose severity of stenosis corresponded to residual stenosis of study subjects at 3-year follow-up. Global peak strain and strain rate measurements in all three directions were decreased before intervention compared with healthy children. Global peak strain and strain rate measurements increased significantly (P stenosis or aortic regurgitation. Copyright © 2012 American Society of Echocardiography. Published by Mosby, Inc. All rights reserved.

  8. Left ventricular regional contraction abnormalities by echocardiographic speckle tracking in combined right bundle branch with left anterior fascicular block compared to left bundle branch block.

    Science.gov (United States)

    Leeters, Irene P M; Davis, Ashlee; Zusterzeel, Robbert; Atwater, Brett; Risum, Niels; Søgaard, Peter; Klem, Igor; Nijveldt, Robin; Wagner, Galen S; Gorgels, Anton P M; Kisslo, Joseph

    2016-01-01

    In contrast to LBBB patients less is known about patients with RBBB+LAFB regarding LV contractile abnormalities and the potential role of CRT. This study investigated whether patients with RBBB+LAFB morphology have echocardiographic mechanical strain abnormalities between the inferior and anterior LV walls, similar to abnormalities between septal and lateral walls in LBBB. Ten healthy volunteers with no-BBB, 28 LBBB and 28 RBBB+LAFB heart failure patients were included in this retrospective study. Two-dimensional regional-strains were obtained by speckle-tracking. Scar was assessed by CMR. Response on echo was defined as normal, classical, borderline or other pattern. The number of classical patterns in LBBB was significantly higher than in RBBB+LAFB and no-BBB groups (pblock: p=0.012). In addition, RBBB+LAFB patients had more scar than LBBB patients (9.9% vs 3.4%, p=0.041), and the average amount of scar in each wall was also higher in RBBB+LAFB (block of the central fascicle, should be assessed in future studies. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Characteristics of myocardial postsystolic shortening in patients with symptomatic hypertrophic obstructive cardiomyopathy before and half a year after alcohol septal ablation assessed by speckle tracking echocardiography.

    Directory of Open Access Journals (Sweden)

    Jiansong Yuan

    Full Text Available OBJECTIVES: Postsystolic shortening (PSS has been proposed as a marker of myocardial dysfunction. Percutaneous transluminal septal myocardial ablation (PTSMA is an alternative therapy for patients with hypertrophic obstructive cardiomyopathy (HOCM that results in sustained improvements in atrial structure and function. We investigated the effects of PTSMA on PSS in HOCM patients using speckle tracking imaging. METHODS: Conventional echocardiographic and PSS parameters were obtained in 18 healthy controls and 30 HOCM patients before and half a year after PTSMA. RESULTS: Compared with the healthy controls, the number of segments having PSS and the average value of PSS were significantly increased in the HOCM patients. At 6 months after PTSMA, both the number of segments having PSS (10.5±2.8 vs. 13.2±2.6; P<0.001 and the average value of PSS (-1.24±0.57 vs. -1.55±0.56; P = 0.009 were significantly reduced. Moreover, the reductions in the average value of PSS correlated well with the reductions in the E-to-Ea ratio (r = 0.705, P<0.001. CONCLUSIONS: Both the number of segments having PSS and the average value of PSS were significantly increased in the HOCM patients. PTSMA has a favourable effect on PSS, which may partly account for the persistent improvement in LV diastolic function in HOCM patients after PTSMA.

  10. Impact of Severe Obesity and Weight Loss on Systolic Left Ventricular Function and Morphology: Assessment by 2-Dimensional Speckle-Tracking Echocardiography

    Directory of Open Access Journals (Sweden)

    Sevda Karimian

    2016-01-01

    Full Text Available Obesity is associated with an increased risk of heart failure. Little is known about the impact of dietary changes on the cardiac sequelae in obese patients. Twenty-one obese subjects underwent a 12-week low calorie fasting phase of a formula diet. Transthoracic two-dimensional speckle-tracking echocardiography was performed to obtain systolic left ventricular strain before and after weight loss. Body mass index decreased significantly from 38.6±6.2 to 31.5±5.3 kg/m2, and the total percentage fat loss was 19%. Weight reduction was associated with a reduction in blood pressure and heart rate. Left ventricular longitudinal global peak systolic strain was in the lower normal range (−18.7±3.2% before weight loss and was unchanged (−18.8±2.4% after 12 weeks on diet with substantial weight loss. Also, no significant change in global radial strain after weight loss was noted (41.1±22.0 versus 43.9±23.3, p=0.09. Left atrial and ventricular dimensions were in normal range before fasting and remained unchanged after weight loss. In our study obesity was associated with normal systolic left ventricular function. A 12-week low calorie diet with successful weight loss can reduce blood pressure and heart rate. Systolic left ventricular function and morphology were not affected by rapid weight reduction.

  11. Two-Dimensional Speckle Tracking Echocardiography Detects Subclinical Left Ventricular Systolic Dysfunction among Adult Survivors of Childhood, Adolescent, and Young Adult Cancer

    Directory of Open Access Journals (Sweden)

    Anthony F. Yu

    2016-01-01

    Full Text Available Two-dimensional speckle tracking echocardiography (2DSTE provides a sensitive measure of left ventricular (LV systolic function and may aid in the diagnosis of cardiotoxicity. 2DSTE was performed in a cross-sectional study of 134 patients (mean age: 31.4±8.8 years; 55% male; mean time since diagnosis: 15.4±9.4 years previously treated with anthracyclines (mean cumulative dose: 320±124 mg/m2, with (n=52 or without (n=82 mediastinal radiotherapy. The prevalence of LV systolic dysfunction, defined as fractional shortening < 27%, LV ejection fraction (LVEF < 55%, and global longitudinal strain (GLS ≤ 16%, was 5.2%, 6.0%, and 23.1%, respectively. Abnormal GLS was observed in 24 (18% patients despite a normal LVEF. Indices of LV systolic function were similar regardless of anthracycline dose. However, GLS was worse (18.0 versus 19.0, p=0.003 and prevalence of abnormal GLS was higher (36.5% versus 14.6%, p=0.004 in patients treated with mediastinal radiotherapy. Mediastinal radiotherapy was associated with reduced GLS (p=0.040 after adjusting for sex, age, and cumulative anthracycline dose. In adult survivors of childhood, adolescent, and young adult cancer, 2DSTE frequently detects LV systolic dysfunction despite a normal LVEF and may be useful for the long-term cardiac surveillance of adult cancer survivors.

  12. Left Ventricular Mechanics in Repaired Tetralogy of Fallot with and without Pulmonary Valve Replacement: Analysis by Three-Dimensional Speckle Tracking Echocardiography

    Science.gov (United States)

    Li, Shu-na; Yu, Wei; Lai, Clare Tik-man; Wong, Sophia J.; Cheung, Yiu-fai

    2013-01-01

    Background Altered septal curvature and left ventricular (LV) geometry secondary to right ventricular (RV) dilation render two-dimensional assessment of LV mechanics difficult in repaired tetralogy of Fallot (TOF) patients. The novel three-dimensional (3D) speckle tracking echocardiography enables comprehensive evaluation of true 3D LV mechanics. Methods and Results Seventy-six patients aged 23.6±8.3 years, 55 with isolated repair (group I) and 21 with subsequent pulmonary valve replacement (group II), and 34 healthy controls were studied. Three-dimensional volume datasets were acquired for assessment of LV global and regional 3D strain, systolic dyssynchrony index (SDI), twist, twist gradient (twist/LV length), and ejection fraction. A global performance index was calculated as (global 3D strain•twist gradient)/SDI. The septal curvature and LV eccentricity were determined from the mid-ventricular short-axis. Compared with controls, group I and II patients had significantly reduced LV global 3D strain, LV twist, twist gradient, septal curvature, and global performance index, and greater LV systolic and diastolic eccentricity and SDI (all prepaired TOF patients with and without pulmonary valve replacement. PMID:24223166

  13. Usefulness of Speckle Tracking Strain Echocardiography for Assessment of Risk of Ventricular Arrhythmias After Placement of a Left Ventricular Assist Device.

    Science.gov (United States)

    Akhabue, Ehimare; Seok Park, Chan; Pinney, Sean; Anyanwu, Anelechi; Chaudhry, Farooq; Narula, Jagat; Nair, Ajith; Sengupta, Partho P

    2017-11-01

    Patients with continuous-flow left ventricular assist devices (LVADs) are at elevated risk of developing ventricular arrhythmias (VA), which can result in right ventricular dysfunction and abnormal LVAD function. Predictors of postoperative VA after LVAD placement are unclear. We hypothesized that global left ventricular circumferential strain (LVCS), a marker of transmural impairment in myocardial function, would independently predict postoperative VA in patients who underwent LVAD implantation. We studied 98 consecutive patients (57 ± 11 years, 83% men) who underwent HeartMate II axial flow LVAD placement. Speckle tracking-derived global circumferential strain was assessed from mid-left ventricular short-axis images. The primary composite end point was defined as any ventricular tachycardia that required intervention (anti-arrhythmic medication, cardioversion, implantable cardioverter defibrillator placement, implantable cardioverter defibrillator shock) or any ventricular fibrillation. A total of 33 patients (34%) experienced the primary end point (median follow-up: 7 months). Reduced LVCS was statistically significantly related to the primary end point (hazard ratio 1.77, 95% confidence interval 1.09 to 2.87 per 1 standard deviation reduction in LVCS, p = 0.02). LVCS above a cut-off value of -9.7% was associated with significantly reduced arrhythmia-free survival (log-rank p = 0.001). In conclusion, global LVCS is an independent predictor of ventricular arrhythmias after LVAD placement. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Subclinical Alterations of Cardiac Mechanics Present Early in the Course of Pediatric Type 1 Diabetes Mellitus: A Prospective Blinded Speckle Tracking Stress Echocardiography Study.

    Science.gov (United States)

    Hensel, Kai O; Grimmer, Franziska; Roskopf, Markus; Jenke, Andreas C; Wirth, Stefan; Heusch, Andreas

    2016-01-01

    Diabetic cardiomyopathy substantially accounts for mortality in diabetes mellitus. The pathophysiological mechanism underlying diabetes-associated nonischemic heart failure is poorly understood and clinical data on myocardial mechanics in early stages of diabetes are lacking. In this study we utilize speckle tracking echocardiography combined with physical stress testing in order to evaluate whether left ventricular (LV) myocardial performance is altered early in the course of uncomplicated type 1 diabetes mellitus (T1DM). 40 consecutive asymptomatic normotensive children and adolescents with T1DM (mean age 11.5 ± 3.1 years and mean disease duration 4.3 ± 3.5 years) and 44 age- and gender-matched healthy controls were assessed using conventional and quantitative echocardiography (strain and strain rate) during bicycle ergometer stress testing. Strikingly, T1DM patients had increased LV longitudinal (p = 0.019) and circumferential (p = 0.016) strain rate both at rest and during exercise (p = 0.021). This was more pronounced in T1DM patients with a longer disease duration (p = 0.038). T1DM patients with serum HbA1c > 9% showed impaired longitudinal (p = 0.008) and circumferential strain (p = 0.005) and a reduced E/A-ratio (p = 0.018). In conclusion, asymptomatic T1DM patients have signs of hyperdynamic LV contractility early in the course of the disease. Moreover, poor glycemic control is associated with early subclinical LV systolic and diastolic impairment.

  15. Quantitative evolutionary dynamics using high-resolution lineage tracking.

    Science.gov (United States)

    Levy, Sasha F; Blundell, Jamie R; Venkataram, Sandeep; Petrov, Dmitri A; Fisher, Daniel S; Sherlock, Gavin

    2015-03-12

    Evolution of large asexual cell populations underlies ∼30% of deaths worldwide, including those caused by bacteria, fungi, parasites, and cancer. However, the dynamics underlying these evolutionary processes remain poorly understood because they involve many competing beneficial lineages, most of which never rise above extremely low frequencies in the population. To observe these normally hidden evolutionary dynamics, we constructed a sequencing-based ultra high-resolution lineage tracking system in Saccharomyces cerevisiae that allowed us to monitor the relative frequencies of ∼500,000 lineages simultaneously. In contrast to some expectations, we found that the spectrum of fitness effects of beneficial mutations is neither exponential nor monotonic. Early adaptation is a predictable consequence of this spectrum and is strikingly reproducible, but the initial small-effect mutations are soon outcompeted by rarer large-effect mutations that result in variability between replicates. These results suggest that early evolutionary dynamics may be deterministic for a period of time before stochastic effects become important.

  16. Fragmented QRS complexes are associated with left ventricular dysfunction in patients with type-2 diabetes mellitus: a two-dimensional speckle tracking echocardiography study.

    Science.gov (United States)

    Bayramoğlu, Adil; Taşolar, Hakan; Kaya, Yasemin; Bektaş, Osman; Kaya, Ahmet; Yaman, Mehmet; Günaydın, Zeki Yüksel

    2017-12-07

    Heart failure may develop independently of coronary artery disease in diabetes mellitus (DM) patients. Fragmented QRS (fQRS) is a marker of myocardial fibrosis or scar tissue and is related to an increase in cardiovascular adverse events. In this study, we examined the utility of speckle tracking echocardiography (STE) in assessing LV function in DM patients with fQRS. The current study included 178 consecutive patients diagnosed with type-2 DM. The patients included were separated into two groups: those with (n = 50) and without (n = 128) fQRS. The two groups were compared by obtaining LV strain values with STE. Statistically significant differences were also identified between fQRS(-) and fQRS (+) groups with respect to Lv-GLS (p multiple linear regression analysis, fQRS (β = -2.077, p = .002) and DM duration (β = -0.216, p = .021) were identified as independent predictors of Lv-GLS. However, fQRS (β = 4.557, p = .001) and minLAVI (β = -2.198, p = .031) were also found to be independent predictors of E/SRivr. We also performed multiple logistic regression analysis and identified Lv-GLS (β = -0.557, p = .001), minLAVI (β = -0.769, p = .001), E/Em ratio (β = 0.650, p = .001) and E/SRivr (β = 0.105, p = .001) as independent predictors of fQRS. Conclusıons: The results of this study revealed that subclinical LV dysfunction was more common in diabetic patients with fQRS. Therefore, determination of fQRS could be an indicator of the diabetic CMP in patients with DM.

  17. Subclinical left ventricular systolic dysfunction in patients with metabolic syndrome: A case-control study using two-dimensional speckle tracking echocardiography.

    Science.gov (United States)

    Moaref, Alireza; Faraji, Majid; Tahamtan, Maryam

    2016-11-01

    The dramatic increase in the prevalence of metabolic syndrome is associated with more increased cardiovascular morbidity and mortality in this group. Some recent studies suggested that metabolic syndrome is associated with increased risk of subclinical left ventricular (LV) systolic dysfunction. In the present cross-sectional case-control study, the utility of two-dimensional speckle tracking echocardiography (STE) was examined to detect early LV systolic dysfunction in this population. A total of 75 clinically asymptomatic subjects with left ventricular ejection fraction (LVEF) ≥ 55%, 39 without metabolic syndrome and 36 with metabolic syndrome, matched for gender and age, were enrolled in this case-control study. Metabolic syndrome was diagnosed using the National Cholesterol Education Program/Adult Treatment Panel III criteria. LV systolic function was assessed by STE-derived global and segmental longitudinal strain (εLL). Global εLL was significantly lower in patients with metabolic syndrome compared with normal population (-18.41 ± 2.20% vs. -21.2 ± 2.1%, P metabolic syndrome in comparison to control group except for basal anteroseptal (-19.95 ± 2.90% vs. -21.15 ± 3.30%, P = 0.106), basal anterolateral (-17.5 ± 5.0% vs. -18.3 ± 4.1%, P = 0.437), and basal inferolateral segments (-18.1 ± 6.3% vs. -18.9 ± 4.1%, P = 0.526). STE-derived longitudinal LV strain (εLL), a marker of subclinical cardiovascular disease, is impaired in asymptomatic individuals with metabolic syndrome and normal LVEF.

  18. Comparison of Electrocardiography Markers and Speckle Tracking Echocardiography for Assessment of Left Ventricular Myocardial Scar Burden in Patients With Previous Myocardial Infarction.

    Science.gov (United States)

    Nestaas, Eirik; Shih, Jhih-Yuan; Smedsrud, Marit K; Gjesdal, Ola; Hopp, Einar; Haugaa, Kristina H; Edvardsen, Thor

    2017-05-01

    Myocardial scar burden is an important prognostic factor after myocardial infarction. This cohort study compared assessment of left ventricle scar burden between pathological Q waves on electrocardiography (ECG), Selvester multiparametric ECG scoring system for scar burden, and global longitudinal strain (GLS) by speckle-tracking echocardiography 6 months after myocardial infarction. The scar burden was defined by late gadolinium enhancement cardiac magnetic resonance as fraction of total left ventricle tissue. ECG measures were presence of pathologic Q waves and Selvester scores. GLS was the average of peak strain from 16 left ventricle segments. In 34 patients aged 58 ± 10 years (mean ± SD), the scar burden was 19% (9, 26) (median [quartiles]) and 79% had scar burden >5%. Patients with scar burden >5% more frequently had pathologic Q waves (63% vs 14%) and had worse Selvester scores (5 [3, 7] vs 0 [0, 1]) and worse GLS (-16.6 ± 2.4% vs -19.9 ± 1.1%). Pathologic Q waves, Selvester scores, ejection fraction, and GLS related to scar burden in univariable analyses. Sensitivity and specificity for detecting scar burden >5% was 63% and 86% (pathologic Q waves), 89% and 86% (Selvester score), 81% and 86% (ejection fraction), 89% and 86% (GLS), and 96% and 71% (combination of Q waves, Selvester score, and GLS). In conclusion, Selvester score and GLS related to scars 6 months after myocardial infarction, and pathologic Q waves were only weakly associated with scar and GLS was associated with scar independently of ECG markers. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Investigation of global and regional myocardial mechanics with 3-dimensional speckle tracking echocardiography and relations to hypertrophy and fibrosis in hypertrophic cardiomyopathy.

    Science.gov (United States)

    Urbano-Moral, Jose Angel; Rowin, Ethan J; Maron, Martin S; Crean, Andrew; Pandian, Natesa G

    2014-01-01

    In hypertrophic cardiomyopathy (HCM), heterogeneous myocardial hypertrophy and fibrosis are responsible for abnormalities of left ventricular (LV) function. We aimed to characterize LV global and regional myocardial mechanics in HCM, according to segmental hypertrophy and fibrosis. Fifty-nine patients with HCM underwent standard echocardiography, 3-dimensional speckle tracking echocardiography, and cardiac magnetic resonance with late gadolinium enhancement (LGE); all 3 tests were <24 hours apart. Longitudinal, circumferential, and area strains were investigated according to the extent of LGE (no LGE, LGE<10%, and LGE≥10%), segmental thickness (≥15 versus <15 mm), and segmental LGE (LGE versus non-LGE). Attenuated global longitudinal strain showed association with extent of hypertrophy (indexed LV mass, r=0.32, P=0.01; maximum LV wall thickness, r=0.34, P=0.009; number of segments≥15 mm, r=0.44, P<0.001), whereas enhanced global circumferential strain was correlated to LV global functional parameters (indexed end-systolic volume, r=0.47, P<0.001; ejection fraction, r=-0.75, P<0.001). Parameters of global myocardial mechanics showed no association with the extent of LGE; in contrast, the extent of LGE was associated with the extent of hypertrophy. All 3 deformation parameters were attenuated both in segments≥15 mm in thickness and in those with LGE; adjusted analysis demonstrated that segmental presence of LGE was associated with additional attenuation in myocardial deformation. Both hypertrophy and fibrosis contribute to regional impairment of myocardial shortening in HCM. The extent of hypertrophy is the primary factor altering global myocardial mechanics. Circumferential myocardial shortening seems to be directly involved in preservation of LV systolic performance in HCM.

  20. Changes in cardiac function and structure in newly diagnosed Graves' disease. A conventional and 2D-speckle tracking echocardiography study.

    Science.gov (United States)

    Aroditis, K; Pikilidou, M; Vourvouri, E; Hadjistavri, L; Zebekakis, P; Yovos, J; Efthimiadis, G; Karvounis, H

    2017-02-01

    Overproduction of thyroid hormones leads to structural as well as functional cardiac changes. Conventional echocardiography but also recently developed sophisticated two-dimensional echocardiography speckle (2D-STE) tracking allow elaborate evaluation of these changes. Our purpose was to investigate the effects of thyroid hormones overproduction on the heart in patients with Graves' disease and changes that occur after 6 months thyrostatic therapy. We conducted a prospective, case-control study of 6 months duration. Full echocardiographic assessment at diagnosis and after 6 months of thyrostatic therapy were performed in 44 patients with Graves' disease, aged 37.6 ± 9.1 years. Additionally, 43 euthyroid controls were studied for the same time period. Left ventricular end diastolic diameter (LVEDD) and left ventricular end systolic diameter (LVESD) were higher in the patient group while triscupid annular plane systolic excursion (TAPSE) was lower in the patient group. Moreover, left ventricular (LV) mass index and left atrium (LA) volume index were higher in the Graves' disease group. Diastolic impairment as assessed with conventional echocardiography including tissue Doppler was present in the patient group (E/A ratio 0.87 ± 0.10,). 2D-STE analysis, revealed an increase in the strain rate at the isovolumic relaxation time (SRIVRT, 0.310 ± 0.07 patients versus 0.298 ± 0.09 s-1 controls). Improvement in diastolic and right systolic function as well as in left ventricular structural parameters was observed after restoration of euthyroidism (E/A ratio from 0.87 ± 0.10 versus 0.9 ± 0.08, p Graves' showed an improvement in diastolic function, right systolic function and structural parameters after 6 months of thyrostatic treatment.

  1. Left ventricular mechanics in repaired tetralogy of Fallot with and without pulmonary valve replacement: analysis by three-dimensional speckle tracking echocardiography.

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    Shu-Na Li

    Full Text Available BACKGROUND: Altered septal curvature and left ventricular (LV geometry secondary to right ventricular (RV dilation render two-dimensional assessment of LV mechanics difficult in repaired tetralogy of Fallot (TOF patients. The novel three-dimensional (3D speckle tracking echocardiography enables comprehensive evaluation of true 3D LV mechanics. METHODS AND RESULTS: Seventy-six patients aged 23.6 ± 8.3 years, 55 with isolated repair (group I and 21 with subsequent pulmonary valve replacement (group II, and 34 healthy controls were studied. Three-dimensional volume datasets were acquired for assessment of LV global and regional 3D strain, systolic dyssynchrony index (SDI, twist, twist gradient (twist/LV length, and ejection fraction. A global performance index was calculated as (global 3D strain•twist gradient/SDI. The septal curvature and LV eccentricity were determined from the mid-ventricular short-axis. Compared with controls, group I and II patients had significantly reduced LV global 3D strain, LV twist, twist gradient, septal curvature, and global performance index, and greater LV systolic and diastolic eccentricity and SDI (all p<0.05. All but the four apical LV segments in patients had reduced regional 3D strain compared with controls (all p<0.05. Septal curvature correlated with LV global 3D strain (r=0.41, p<0.001, average septal strain (r=0.38, p<0.001, twist (r=0.32, p<0.001, twist gradient (r=0.33, p<0.001, and global performance index (r=0.43, p<0.001. CONCLUSIONS: Adverse 3D LV mechanics as characterized by impaired global and regional 3D systolic strain, mechanical dyssynchrony, and reduced twist is related to reduced septal curvature in repaired TOF patients with and without pulmonary valve replacement.

  2. Mechanical and substrate abnormalities of the left atrium assessed by 3-dimensional speckle-tracking echocardiography and electroanatomic mapping system in patients with paroxysmal atrial fibrillation.

    Science.gov (United States)

    Watanabe, Yoshikazu; Nakano, Yukiko; Hidaka, Takayuki; Oda, Noboru; Kajihara, Kenta; Tokuyama, Takehito; Uchimura, Yuko; Sairaku, Akinori; Motoda, Chikaaki; Fujiwara, Mai; Kawazoe, Hiroshi; Matsumura, Hiroya; Kihara, Yasuki

    2015-03-01

    Left atrial (LA) remodeling progresses to electrical remodeling, contractile remodeling, and subsequently structural remodeling. Little is known about the relationship between LA electrical and anatomical remodeling and LA mechanical function. We aimed to clarify the relationship between LA mechanical function using 3-dimensional speckle-tracking echocardiography (3D-STE) and LA electrical remodeling using an electroanatomic mapping system (CARTO 3) and to estimate atrial fibrillation (AF) substrate in patients with paroxysmal AF (PAF). A total of 52 patients with PAF (41 (79%) men; mean age 61 ± 11 years) undergoing their initial pulmonary vein isolation (PVI) were examined. The standard deviation of the time to peak strain in each LA segment (%SD-TPS) was analyzed as an index of LA dyssynchrony using 3D-STE before PVI. Contact LA bipolar voltage and activation maps were constructed during sinus rhythm before PVI using CARTO 3. The LA total activation time was measured and low-voltage zones (LVZs) were determined with a local bipolar electrogram amplitude of <0.5 mV. The patients were divided into those with an LVZ (LVZ group; n = 23) and those without an LVZ (non-LVZ group; n = 29). The %SD-TPS was significantly higher (14.1 ± 5.7 vs 8.0 ± 5.1; P=.0002) in the LVZ group than in the non-LVZ group and was an independent determinant of the LVZ (odds ratio 1.21; 95% confidence interval 1.04-1.49; P=.01). In addition, the LA total activation time was weakly correlated with the %SD-TPS. LA dyssynchrony and conduction delay exist in patients with PAF. The 3D-STE enabled noninvasive estimation of LA electrical remodeling and AF substrate. Copyright © 2015 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  3. Global area strain is a sensitive marker of subendocardial damage in adults after optimal repair of aortic coarctation: three-dimensional speckle-tracking echocardiography data.

    Science.gov (United States)

    Kowalik, Ewa; Kowalski, Mirosław; Klisiewicz, Anna; Hoffman, Piotr

    2016-11-01

    Aortic coarctation (CoA) in adults is associated with reduced survival. Despite successful repair, some unfavorable changes in the left ventricular (LV) myocardial function are reported. Three-dimensional speckle-tracking imaging (3D-STE) is a novel method that allows to assess regional myocardial function in all directions simultaneously and to calculate global area strain which integrates longitudinal and circumferential deformation. The aim of our study was to assess whether 3-D STE provides any new characteristics of LV deformation in patients with optimal CoA repair. Adults after CoA correction underwent transthoracic echocardiographic examinations. Patients with significant concomitant lesions were ruled out. Global longitudinal strain (GLS), global circumferential strain (GCS), global area strain (GAS), and global radial strain (GRS) were assessed using 3D-STE (Echopac Software, GE). The data were compared with those obtained from healthy subjects. 26 adults (9F/17M; mean age 24.4 years) with repaired CoA were studied. Despite preserved LVEFs, patients with repaired CoA had decreased GAS compared with controls (-28.8 vs. -31.7 %; p = 0.007). No differences between patients and healthy subjects in terms of GLS, GCS and GRS were observed. We found a significant correlation between mean blood pressure and GAS (R = 0.39; p < 0.05). No significant influence of age at repair, CoA correction method or LV mass on three-dimensional deformation was observed. Summarizing, global area strain derived from 3D-STE may be a sensitive indicator of subclinical LV dysfunction in patients after optimal repair of CoA. Mean blood pressure, but not age at correction seems to determine LV deformation.

  4. Possible link between strain ST-T change on the electrocardiogram and subendocardial dysfunction assessed by two-dimensional speckle-tracking echocardiography.

    Science.gov (United States)

    Nishikage, Tomoko; Takeuchi, Masaaki; Nakai, Hiromi; Otsuji, Yutaka; Lang, Roberto M

    2010-06-01

    Strain ST-T changes on surface electrocardiogram (ECG) may reflect subendocardial dysfunction. We hypothesized that strain ST-T changes are associated with (i) decrease in longitudinal strain, (ii) decrease in early systolic clockwise twist and early diastolic untwisting, and (iii) augmentation of peak twist due to subendocardial dysfunction. Three levels of left ventricular (LV) short-axis views and three LV apical views were acquired in 46 hypertensive patients with LV hypertrophy and 23 age-matched control subjects using 2D echocardiography. Patients were divided into two groups according to the presence (n = 18) or absence (n = 28) of strain ST-T change on 12-lead ECG. Using 2D strain software, longitudinal, radial, and circumferential strain were measured. Early systolic clockwise twist, end-systolic twist, and untwisting at early diastole were measured from time-domain LV twist curves. No significant intergroup differences in LV ejection fraction were noted. Longitudinal strain was significantly reduced in hypertensive patients with strain ST-T changes compared with those without these changes or control subjects. Although LV twist at end-systole was similar between patients with and without strain ST-T changes, early systolic clockwise twist and untwisting was significantly reduced in strain ST-T change group compared with the no ST-T change group. Multivariate analysis revealed that not LV mass index but strain ST-T change was an independent predictor of global longitudinal strain. The reduction in longitudinal strain, early systolic clockwise twist, and untwisting in hypertensive patients with strain ST-T changes suggests possible link between this ECG abnormality and subendocardial dysfunction, which can be assessed by 2D speckle tracking echocardiography.

  5. Subendocardial dysfunction in patients with chronic severe aortic regurgitation and preserved ejection fraction detected with speckle-tracking strain imaging and transmural myocardial strain profile.

    Science.gov (United States)

    Kaneko, Akihiro; Tanaka, Hidekazu; Onishi, Tetsuari; Ryo, Keiko; Matsumoto, Kensuke; Okita, Yutaka; Kawai, Hiroya; Hirata, Ken-Ichi

    2013-04-01

    It remains difficult to detect subtle left ventricular (LV) myocardial dysfunction in chronic aortic regurgitation (AR) patients with the preserved ejection fraction (EF). We studied 36 chronic severe AR patients undergoing surgical correction with the EF of 58 ± 6% (all ≥ 50%). Echocardiography was performed before and 12 ± 8 months after surgical correction. We used two-dimensional speckle-tracking strain imaging to evaluate global radial strain in the inner-half (GRSinner), outer-half (GRSouter), and total (GRStotal) layer from the mid-LV short-axis view. We also evaluated the transmural strain profile in the LV posterior wall by using myocardial tissue Doppler radial strain, and the location of peak strain was determined as the percentage of the distance from the endocardium to the epicardium accounted for by the wall thickness. Fifteen EF-matched normal volunteers were studied for comparison. GRSinner for AR patients was significantly smaller than that for controls (28.9 ± 12.9 vs. 37.1 ± 9.1%, P = 0.032), and the location of peak strain had significantly shifted to the epicardial side compared with that in controls (27.1 ± 14.0-13.2 ± 4.8%, P = 0.001). In contrast, GRStotal and GRSouter were similar for the two groups. After surgical correction, EF increased from 58 ± 6 to 62 ± 7% (P = 0.018), GRSinner from 27.8 ± 12.5 to 37.7 ± 14.6% (P < 0.0001), and the location of peak strain significantly shifted to the endocardial side (26.9 ± 13.9-19.1 ± 11.9%, P = 0.028). However, GRStotal and GRSouter did not change. The LV endocardium side, impaired in chronic AR patients with the preserved EF, improved after surgical correction. Our observations may prove useful for evaluating subtle early changes in such patients.

  6. Enhanced Right-Chamber Remodeling in Endurance Ultra-Trail Athletes Compared to Marathon Runners Detected by Standard and Speckle-Tracking Echocardiography

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    Kristian Ujka

    2017-07-01

    Full Text Available Background: Strenuous and endurance exercise training have been associated with morphological and functional heart remodeling. Two-dimensional speckle-tracking echocardiography (STE is a novel technique that allows an accurate quantification of global myocardium deformation. Our aim was to evaluate together left and right cardiac remodeling in different long-distance running athletes: marathon runners (42 km (M and endurance mountain runners (>300 Km (UT.Methods: A total of 92 athletes (70 males, 76% including 47 M [age 45 ± 7 years; training: 18 (9–53 years*days/week], 45 UT [age 42 ± 9, training: 30 (15–66 years*days/week] underwent conventional echocardiography and STE (Beyond Diogenes 2.0, AMID during the agonistic season.Results: Right ventricle (RV end-diastolic area (p = 0.026, fractional area changing (FAC (p = 0.008 and RV global longitudinal strain (GLS were significantly increasedin UT athletes. Furthermore, UT showed larger right atrium (RA volume (p = 0.03, reduced RA GLS and significantly increased RA global circumferential strain (GCS compared to M. After adjustment for age, sex, and HR as covariates, UT showed a reduced RA GLS (OR 0.907; CI 0.856–0.961 and increased RV FAC (OR 1.172; CI: 1.044–1.317 compared to M.Conclusion: Athletes enrolled in UT endurance activities showed RV and RA morphological and functional remodeling to increased preload in comparison with M runners characterized by increased RV FAC and reduced RA GLS. Follow-up studies are needed to better assess the long-term clinical impact of these modifications. 2D STE is a useful tool for investigating the deformation dynamic in different sports specialties.

  7. Quantification of Coupled Stiffness and Fiber Orientation Remodeling in Hypertensive Rat Right-Ventricular Myocardium Using 3D Ultrasound Speckle Tracking with Biaxial Testing.

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    Dae Woo Park

    Full Text Available Mechanical and structural changes of right ventricular (RV in response to pulmonary hypertension (PH are inadequately understood. While current standard biaxial testing provides information on the mechanical behavior of RV tissues using surface markers, it is unable to fully assess structural and mechanical properties across the full tissue thickness. In this study, the mechanical and structural properties of normotensive and pulmonary hypertension right ventricular (PHRV myocardium through its full thickness were examined using mechanical testing combined with 3D ultrasound speckle tracking (3D-UST. RV pressure overload was induced in Sprague-Dawley rats by pulmonary artery (PA banding. The second Piola-Kirchhoff stress tensors and Green-Lagrangian strain tensors were computed in the RV myocardium using the biaxial testing combined with 3D-UST. A previously established non-linear curve-fitting algorithm was applied to fit experimental data to a Strain Energy Function (SEF for computation of myofiber orientation. The fiber orientations obtained by the biaxial testing with 3D-UST compared well with the fiber orientations computed from the histology. In addition, the re-orientation of myofiber in the right ventricular free wall (RVFW along longitudinal direction (apex-to-outflow-tract direction was noticeable in response to PH. For normotensive RVFW samples, the average fiber orientation angles obtained by 3D-UST with biaxial test spiraled from 20° at the endo-cardium to -42° at the epi-cardium (Δ = 62°. For PHRV samples, the average fiber orientation angles obtained by 3D-UST with biaxial test had much less spiral across tissue thickness: 3° at endo-cardium to -7° at epi-cardium (Δ = 10°, P<0.005 compared to normotensive.

  8. Assessment of myocardial viability in patients with acute myocardial infarction by two-dimensional speckle tracking echocardiography combined with low-dose dobutamine stress echocardiography.

    Science.gov (United States)

    Gong, Lei; Li, Dongye; Chen, Junhong; Wang, Xiaoping; Xu, Tongda; Li, Wenhua; Ren, Shaoyang; Wang, Cheng

    2013-06-01

    It is clinically important to determine the myocardial viability of regional wall motion abnormality segments in patients with acute myocardial infarction (AMI). The purpose of this study was to ascertain the ability and value of a combination of speckle tracking echocardiography (STE) and low dose dobutamine stress echocardiography (LDDSE) for the evaluation of viable myocardium in patients with AMI. Forty-two hospitalized patients with AMI and left ventricular systolic dysfunction (left ventricular ejection fraction <50%) were underwent STE in conjunction with LDDSE and dual isotope simultaneous acquisition single photon emission computed tomography (DISA-SPECT). Percutaneous coronary intervention (PCI) was performed subsequently in all patients. STE was used to measure radial, circumferential, and longitudinal end-systolic strain and peak systolic strain rate. The movement of each segment was observed by routine echocardiography 1, 3, and 6 months after PCI, and its improvement over time was the criterion of viable myocardium. The sensitivity, specificity and accuracy of DISA-SPECT for the assessment of viable myocardium were 83.6, 74.4, and 80.7%, respectively. Among the radial, circumferential, and longitudinal strain and strain rate parameters, only longitudinal strain (LS) and longitudinal strain rate (LSr) at rest and LDDSE emerged as independent predictors of viable myocardium, When combining LS and LSr at LDDSE, the sensitivity, specificity and accuracy for the assessment of viable myocardium rose to 89.8, 90.2 and 89.9%, respectively. The sensitivity of STE in conjunction with LDDSE was similar to DISA-SPECT for detecting viable myocardium in patients with AMI, but the specificity and accuracy of STE performed with LDDSE were higher than DISA-SPECT.

  9. Impaired right and left ventricular function in asymptomatic children with repaired tetralogy of Fallot by two-dimensional speckle tracking echocardiography study.

    Science.gov (United States)

    Li, Yuman; Xie, Mingxing; Wang, Xinfang; Lu, Qing; Zhang, Li; Ren, Pingping

    2015-01-01

    Early detection of right ventricular (RV) and left ventricular (LV) dysfunction in patients with repaired tetralogy of Fallot (TOF) is essential because dysfunction is correlated with a poor clinical outcome. The aim of this study was to assess RV and LV function in asymptomatic children with repaired TOF by two-dimensional ultrasound speckle tracking echocardiography (STE). Fifty-six asymptomatic children with a preserved biventricular ejection fraction (EF) after repair of TOF and 35 healthy control subjects were studied. RV and LV strain and strain rate were measured by STE. RVEF and pulmonary regurgitation (PR) were assessed using cardiac magnetic resonance imaging. Compared with the control subjects, RV regional longitudinal strain and strain rate and global longitudinal strain (GLS) and strain rate (GLSR) were impaired in children with repaired TOF. Likewise, LV circumferential and radial strain and strain rate were reduced in patients with TOF. In contrast, longitudinal strain and strain rate did not differ between the groups. RV and LV GLSR were correlated with postoperative follow-up period (r1 = -0.44; r2 = -0.48). RV GLS and GLSR were associated with RVEF (r1 = 0.64; r2 = 0.60) and PR (r1 = -0.48; r2 = -0.49). LV circumferential strain rate was related to PR (r = -0.45). STE can identify abnormalities that may represent early impairment of RV and LV systolic function in postoperative TOF patients with a preserved EF. PR is associated with decreased biventricular performance in repaired patients. STE-derived strain and strain rate may be useful indices for detecting the early deterioration of biventricular performance in patients with TOF. © 2014, Wiley Periodicals, Inc.

  10. Speckle imaging algorithms for planetary imaging

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    Johansson, E. [Lawrence Livermore National Lab., CA (United States)

    1994-11-15

    I will discuss the speckle imaging algorithms used to process images of the impact sites of the collision of comet Shoemaker-Levy 9 with Jupiter. The algorithms use a phase retrieval process based on the average bispectrum of the speckle image data. High resolution images are produced by estimating the Fourier magnitude and Fourier phase of the image separately, then combining them and inverse transforming to achieve the final result. I will show raw speckle image data and high-resolution image reconstructions from our recent experiment at Lick Observatory.

  11. Overview of Single-Molecule Speckle (SiMS) Microscopy and Its Electroporation-Based Version with Efficient Labeling and Improved Spatiotemporal Resolution.

    Science.gov (United States)

    Yamashiro, Sawako; Watanabe, Naoki

    2017-07-06

    Live-cell single-molecule imaging was introduced more than a decade ago, and has provided critical information on remodeling of the actin cytoskeleton, the motion of plasma membrane proteins, and dynamics of molecular motor proteins. Actin remodeling has been the best target for this approach because actin and its associated proteins stop diffusing when assembled, allowing visualization of single-molecules of fluorescently-labeled proteins in a state specific manner. The approach based on this simple principle is called Single-Molecule Speckle (SiMS) microscopy. For instance, spatiotemporal regulation of actin polymerization and lifetime distribution of actin filaments can be monitored directly by tracking actin SiMS. In combination with fluorescently labeled probes of various actin regulators, SiMS microscopy has contributed to clarifying the processes underlying recycling, motion and remodeling of the live-cell actin network. Recently, we introduced an electroporation-based method called eSiMS microscopy, with high efficiency, easiness and improved spatiotemporal precision. In this review, we describe the application of live-cell single-molecule imaging to cellular actin dynamics and discuss the advantages of eSiMS microscopy over previous SiMS microscopy.

  12. Overview of Single-Molecule Speckle (SiMS Microscopy and Its Electroporation-Based Version with Efficient Labeling and Improved Spatiotemporal Resolution

    Directory of Open Access Journals (Sweden)

    Sawako Yamashiro

    2017-07-01

    Full Text Available Live-cell single-molecule imaging was introduced more than a decade ago, and has provided critical information on remodeling of the actin cytoskeleton, the motion of plasma membrane proteins, and dynamics of molecular motor proteins. Actin remodeling has been the best target for this approach because actin and its associated proteins stop diffusing when assembled, allowing visualization of single-molecules of fluorescently-labeled proteins in a state specific manner. The approach based on this simple principle is called Single-Molecule Speckle (SiMS microscopy. For instance, spatiotemporal regulation of actin polymerization and lifetime distribution of actin filaments can be monitored directly by tracking actin SiMS. In combination with fluorescently labeled probes of various actin regulators, SiMS microscopy has contributed to clarifying the processes underlying recycling, motion and remodeling of the live-cell actin network. Recently, we introduced an electroporation-based method called eSiMS microscopy, with high efficiency, easiness and improved spatiotemporal precision. In this review, we describe the application of live-cell single-molecule imaging to cellular actin dynamics and discuss the advantages of eSiMS microscopy over previous SiMS microscopy.

  13. Overview of Single-Molecule Speckle (SiMS) Microscopy and Its Electroporation-Based Version with Efficient Labeling and Improved Spatiotemporal Resolution

    Science.gov (United States)

    Yamashiro, Sawako; Watanabe, Naoki

    2017-01-01

    Live-cell single-molecule imaging was introduced more than a decade ago, and has provided critical information on remodeling of the actin cytoskeleton, the motion of plasma membrane proteins, and dynamics of molecular motor proteins. Actin remodeling has been the best target for this approach because actin and its associated proteins stop diffusing when assembled, allowing visualization of single-molecules of fluorescently-labeled proteins in a state specific manner. The approach based on this simple principle is called Single-Molecule Speckle (SiMS) microscopy. For instance, spatiotemporal regulation of actin polymerization and lifetime distribution of actin filaments can be monitored directly by tracking actin SiMS. In combination with fluorescently labeled probes of various actin regulators, SiMS microscopy has contributed to clarifying the processes underlying recycling, motion and remodeling of the live-cell actin network. Recently, we introduced an electroporation-based method called eSiMS microscopy, with high efficiency, easiness and improved spatiotemporal precision. In this review, we describe the application of live-cell single-molecule imaging to cellular actin dynamics and discuss the advantages of eSiMS microscopy over previous SiMS microscopy. PMID:28684722

  14. Dynamical properties of speckled speckles

    DEFF Research Database (Denmark)

    Hanson, Steen Grüner; Iversen, Theis Faber Quist; Hansen, Rene Skov

    2010-01-01

    the static diffuser and the plane of observation consist of an optical system that can be characterized by a complex-valued ABCD-matrix (e.g. simple and complex imaging systems, free space propagation in both the near-and far-field, and Fourier transform systems). The use of the complex ABCD-method means...... to be Gaussian but the derived expressions are not restricted to a plane incident beam. The results are applicable for speckle-based systems for determining mechanical displacements, especially for long-range systems, and for analyzing systems for measuring biological activity beyond a diffuse layer, e.g. blood...

  15. Microscopy using randomized speckle illumination

    Science.gov (United States)

    Perinchery, Sandeep M.; Shinde, Anant; Murukeshan, V. M.

    2017-06-01

    It is well known for structured illumination microscopy (SIM) that the lateral resolution by a factor of two beyond the classical diffraction limit is achieved using spatially structured illumination in wide-field fluorescence microscope. In the state of art SIM systems, grating patterns are generally generated by physical gratings or by spatial light modulators such as digital micro mirrors (DMD), liquid crystal displays (LCD). In this study, using a combination of LCD and ground glasses, size controlled randomized speckle patterns are generated as an illumination source for the microscope. Proof of concept of using speckle illumination in SIM configuration is tested by imaging fixed BPAE cells.

  16. Evaluation of the role of left atrial strain using two-dimensional speckle tracking echocardiography in patients with diabetes mellitus and heart failure with preserved left ventricular ejection fraction.

    Science.gov (United States)

    Georgievska-Ismail, Ljubica; Zafirovska, Planinka; Hristovski, Zarko

    2016-11-01

    To evaluate additional role of left atrial two-dimensional speckle tracking echocardiography in patients with diabetes mellitus type 2, 218 patients with heart failure with preserved left ventricular ejection fraction divided according to the presence of diabetes mellitus (108 with and 110 without) were enrolled in the study. Traditional parameters using two-dimensional echocardiography and Doppler imaging were measured as expressions of left ventricular diastolic function as well as peak atrial longitudinal strain and peak atrial contraction strain were measured using two-dimensional speckle tracking echocardiography. Global average peak atrial longitudinal strain and peak atrial contraction strain were significantly lower in patients with diabetes mellitus (p = 0.002 and p = 0.001, respectively) and its reduced values were significantly associated with higher prevalence of diabetes mellitus (p = 0.002 and p = 0.001, respectively), its greater severity (p = 0.002 and p = 0.016, respectively) and longer duration only for global average peak atrial longitudinal strain (p = 0.030). Multiple linear regression analysis demonstrated that the presence of diabetes mellitus appeared as independent predictor of reduced global peak atrial longitudinal strain [B = -2.173; 95% confidence interval: -3.870 to (-0.477); p = 0.012] as well of reduced global peak atrial contraction strain [B = -1.30; 95% confidence interval: -2.234 to (-0.366); p = 0.007]. Two-dimensional speckle tracking echocardiography appeared as a useful additional tool for detection of left atrial dysfunction in patients with heart failure who have preserved left ventricular ejection fraction and diabetes mellitus who are especially prone to develop cardiovascular complications. © The Author(s) 2016.

  17. TRACK-TWO DIPLOMACY AS A RESOLUTION APPROACH TO INTERNATIONAL AND INTER-SOCIETAL CONFLICTS

    Directory of Open Access Journals (Sweden)

    MUZAFFER ERCAN YILMAZ

    2013-06-01

    Full Text Available This work provides a descriptive discussion for one of the new conflict resolution approaches, track-two diplomacy. The study discusses both strengths and weaknesses of the approach in detail, concluding that as a part of broader conflict resolution efforts, track-two diplomacy may be very useful, despite its practical shortcomings, to overcome psychological barriers between the parties, to make them understand their issue mutually, to produce new insights for resolution, and to create a psychological maturity for a negotiated agreement. Thus, it is stressed that track-two diplomacy should be utilized to complement formal negotiation process in resolving international and inter-societal conflicts.

  18. High Momentum Resolution tracking In a Linear Collider

    CERN Document Server

    Ljunggren, M; Oskarsson, A

    2011-01-01

    The work in this thesis has been made within the LCTPC-collaboration, an international collaboration for studying the technical aspects af a possible tracking detector at a linear collider. The collaboration has built a prototype Time Projection Chamber (TPC) for testing the properties of dierent readout structures. A TPC is a tracking detector consisting of a gas lled drift volume placed in a solenoidal magnetic eld where the readout is made using a segmented plane of so called pads. When a char...

  19. Antineoplastic-related cardiotoxicity, morphofunctional aspects in a murine model: contribution of the new tool 2D-speckle tracking

    Directory of Open Access Journals (Sweden)

    Coppola C

    2016-11-01

    Full Text Available Carmela Coppola,1 Gennaro Riccio,1 Antonio Barbieri,2 Maria Gaia Monti,3 Giovanna Piscopo,1 Domenica Rea,2 Claudio Arra,2 Carlo Maurea,1 Claudia De Lorenzo,4,5 Nicola Maurea1 1Division of Cardiology, Istituto Nazionale per lo Studio e la Cura dei Tumori “Fondazione G. Pascale”, IRCCS, Naples, Italy; 2Animal Facility Unit, Department of Experimental Oncology, Istituto Nazionale per lo Studio e la Cura dei Tumori “Fondazione G. Pascale”, IRCCS, Naples, Italy; 3Department of Translational Medical Sciences, University Federico II, Naples, Italy; 4Department of Molecular Medicine and Medical Biotechnology, University Federico II, Naples, Italy; 5CEINGE Biotecnologie Avanzate, Naples, Italy Objective: Considering that global left ventricular systolic radial strain is a sensitive technique for the early detection of left ventricular dysfunction due to antineoplastics and the analysis of segmental myocardial contractility, we evaluated this technique for early detection of trastuzumab-related cardiotoxicity by comparing it with cardiac structural damage.Methods: Groups of six mice were injected with trastuzumab or doxorubicin, used either as single agents or in combination. Cardiac function was evaluated by transthoracic echocardiography measurements before and after treatment for 2 or 7 days, by using a Vevo 2100 high-resolution imaging system. After echocardiography, mice were euthanized, and hearts were processed for histological evaluations, such as cardiac fibrosis, apoptosis, capillary density, and inflammatory response.Results: Trastuzumab-related cardiotoxicity was detected early by 2D strain imaging. Radial strain was reduced after 2 days in mice treated with trastuzumab alone (21.2%±8.0% vs 40.5%±4.8% sham; P<0.01. Similarly, trastuzumab was found to induce apoptosis, capillary density reduction, and inflammatory response in cardiac tissue after 2 days of treatment, in a fashion similar to doxorubicin. On the contrary, fractional

  20. Laser speckle and related phenomena

    CERN Document Server

    Dainty, John Christopher; Françon, Maurice; Goodman, Joseph Wilfred; McKechnie, Thomas Stewart; Parry, Gareth

    1975-01-01

    Contents: Dainty, J. C.: Introduction. - Goodman, J. W.: Statistical Properties of Laser Speckle Patterns. - Parry, G.: Speckle Patterns in Partially Coherent Light. - McKechnie, T. S.: Speckle Reduction. - Francon, M.: Information Processing Using Speckle Patterns. - Ennos, A. E.: Speckle Interferometry. - Dainty, J. C.: Stellar Speckle Interferometry. - Dainty, J. C.: Recent Developments. - Subject Index.

  1. Left atrial strain assessed by three-dimensional speckle tracking echocardiography predicts atrial fibrillation recurrence after catheter ablation in patients with paroxysmal atrial fibrillation.

    Science.gov (United States)

    Mochizuki, Atsushi; Yuda, Satoshi; Fujito, Takefumi; Kawamukai, Mina; Muranaka, Atsuko; Nagahara, Daigo; Shimoshige, Shinya; Hashimoto, Akiyoshi; Miura, Tetsuji

    2017-06-01

    Several studies have shown the utility of left atrial (LA) function determined by two-dimensional or three-dimensional speckle tracking echocardiography (2D- or 3D-STE) for identifying patients with paroxysmal atrial fibrillation (AF). However, whether 3D-STE is applicable for prediction of the recurrence of AF after catheter ablation (CA) remains unknown. We examined whether any 3D-STE parameters are better than 2D-STE parameters for the prediction of AF recurrence. Forty-two patients with paroxysmal AF (58 ± 10 years old, 69% male) underwent 2D- and 3D-STE within 3 days before first-time CA. The global peak LA longitudinal, circumferential, and area strains during systole (3D-GLSs, -GCSs, and -GASs, respectively) and those just before atrial contraction (3D-GLSa, -GCSa, and -GASa, respectively) were determined by 3D-STE and standard deviations of times to peaks of regional LA strains were calculated as indices of LA dyssynchrony. In 2D-STE, global LA longitudinal strains during systole and just before atrial contraction (2D-GLSs and -GLSa) were determined. During follow-up of 441 ± 221 days, 12 patients (29%) had AF recurrence. In the univariate Cox proportional hazard analysis, age [hazard ratio (HR): 1.08, p = 0.04], 3D-GCSs (HR: 0.91, p = 0.03), and 3D-GASs (HR: 0.95, p = 0.01) were predictors of AF recurrence, though associations of recurrence with 2D-STE parameters, indices of LA synchrony, and LA volume were not significant. Multivariable analysis showed that 3D-GASs was an independent predictor of AF recurrence (HR: 0.96, p = 0.048). LA strain determined by 3D-STE is a novel and better predictor of AF recurrence after CA than that determined by 2D-STE or other known predictors.

  2. [Early detection of the cardiotoxicity induced by chemotherapy drug through two-dimensional speckle tracking echocardiography combined with high-sensitive cardiac troponin T].

    Science.gov (United States)

    Wang, W; Kang, Y; Shu, X H; Shen, X D; He, B

    2017-11-23

    Objective: To investigate the clinical value of two-dimensional speckle tracking echocardiography(2D-STE) combined with high-sensitive cardiac troponin T (hs-cTnT) in early detection of the cardiotoxicity induced by chemotherapy drug. Methods: Seventy-five non-Hodgkin's lymphoma patients who received the CHOP regimen were recruited in this study. Conventional echocardiography and 2D-STE were performed on these patients before chemotherapy, the second day after the third course of chemotherapy (during chemotherapy) and the second day after the last course of chemotherapy (after chemotherapy). The parameters included left ventricular ejection fraction (LVEF), global longitudinal strain (LS), global circumferential strain (CS) and global radial strain (RS). The serum hs-cTNT levels were tested simultaneously. Results: Three cycles of CHOP were completed in 30 patients and 6-8 cycles of CHOP were completed in 45 patients. The LVEF of 75 patients before, during and after chemotherapy was (63.8±2.6)%, (63.8±2.8)% and (64.0±3.3)%, respectively, without significant difference (P=0.91). However, the LS of 75 patients before, during and after chemotherapy was (-18.5±1.7)%, (-16.5±1.9)% and (-16.0±1.6)%, respectively. The CS was (-20.9±2.9)%, (-19.3±3.5)% and (-19.2±3.2)%, respectively. The RS was (39.2±6.4)%, (35.3±5.2)% and (35.0±6.2)%, respectively. The hs-cTnT was (0.001 0±0.002 0)ng/ml, (0.006 3±0.008 9)ng/ml and (0.007 3±0.003 8)ng/ml, respectively. The LS, CS and RS were significantly decreased while hs-cTnT was significantly increased during chemotherapy when compared to those before chemotherapy (all of Pchemotherapy were marginally different from those during chemotherapy (all of P>0.05). Moreover, T(LS-SD), T(CS-SD) and T(RS-SD) showed no significant difference before, during and after chemotherapy (all of P>0.05). The reduction of LS was positively associated with the enhancement of hs-cTnT after chemotherapy (r=0.60, P<0.01). Conclusion: 2D

  3. Impact of revascularization of coronary chronic total occlusion on left ventricular function and electrical stability: analysis by speckle tracking echocardiography and signal-averaged electrocardiogram.

    Science.gov (United States)

    Sotomi, Yohei; Okamura, Atsunori; Iwakura, Katsuomi; Date, Motoo; Nagai, Hiroyuki; Yamasaki, Tomohiro; Koyama, Yasushi; Inoue, Koichi; Sakata, Yasushi; Fujii, Kenshi

    2017-06-01

    The present study aimed to assess the mechanisms of effects of percutaneous coronary intervention (PCI) for chronic total occlusion (CTO) from two different aspects: left ventricular (LV) systolic function assessed by two-dimensional speckle tracking echocardiography (2D-STE) and electrical stability evaluated by late potential on signal-averaged electrocardiogram (SAECG). We conducted a prospective observational study with consecutive CTO-PCI patients. 2D-STE and SAECG were performed before PCI, and after 1-day and 3-months of procedure. 2D-STE computed global longitudinal strain (GLS) and regional longitudinal strain (RLS) in CTO area, collateral blood-supplying donor artery area, and non-CTO/non-donor area. A total of 37 patients (66 ± 11 years, 78% male) were analyzed. RLS in CTO and donor areas and GLS were significantly improved 1-day after the procedure, but these improvements diminished during 3 months. The improvement of RLS in donor area remained significant after 3-months the index procedure (pre-PCI -13.4 ± 4.8% vs. post-3M -15.1 ± 4.5%, P = 0.034). RLS in non-CTO/non-donor area and LV ejection fraction were not influenced. Mitral annulus velocity was improved at 3-month follow-up (5.0 ± 1.4 vs. 5.6 ± 1.7 cm/s, P = 0.049). Before the procedure, 12 patients (35%) had a late potential. All components of the late potential (filtered QRS duration, root-mean-square voltage in the terminal 40 ms, and duration of the low amplitude signal <40 μV) were not improved. CTO-PCI improved RLS in the donor area at 3-month follow-up without changes of LV ejection fraction. Although higher prevalence of late potential in the current population compared to healthy population was observed, late potential as a surrogate of arrhythmogenic substrate was not influenced by CTO-PCI.

  4. Left ventricular systolic dysfunction in asymptomatic Marfan syndrome patients is related to the severity of gene mutation: insights from the novel three dimensional speckle tracking echocardiography.

    Directory of Open Access Journals (Sweden)

    Mohamed Abd El Rahman

    Full Text Available In asymptomatic Marfan syndrome (MFS patients we evaluated the relationship between the types of fibrillin-1 (FBN1 gene mutation and possible altered left ventricular (LV function as assessed by three-dimensional speckle tracking echocardiography (3D-STE.Forty-five MFS patients (mean age 24 ± 15 years and 40 age-matched healthy controls were studied. Genetic evaluation for the FBN1 gene was carried on 32 MFS patients. Gene mutation (n = 15, 47% was classified as mild when the mutation resulted in nearly normally functioning protein, while mutations resulting in abnormally function protein were considered to be severe (n = 17, 53%. All patients and controls underwent 3D-STE for evaluation of LV function by an echocardiographer blinded to the results of the genetic testing. Compared to controls, MFS patients had significantly lower 3D-STE derived LV ejection fraction (EF, 57.43 ± 7.51 vs. 62.69 ± 4.76%, p = 0.0001, global LV longitudinal strain (LS, 14.85 ± 2.89 vs. 17.90 ± 2.01%, p = 0.0001, global LV circumferential strain (CS, 13.93 ± 2.81 vs. 16.82 ± 2.17%, p = 0.0001 and global LV area strain (AS, 25.76 ± 4.43 vs. 30.51 ± 2.61%, p = 0.0001. Apart from the global LV LS all these parameters were significantly lower in patients with severe gene mutation than in those with mild mutation (p < 0.05. In the multivariate linear regression analysis only the type of mutation had a significant influence on the 3D-STE derived LVEF (p = 0.017, global CS (p = 0.005 and global AS (p = 0.03.In asymptomatic MFS patients latent LV dysfunction can be detected using 3D STE. The LV dysfunction is mainly related to the severity of gene mutation, suggesting possible primary cardiomyopathy in MFS patients.

  5. Cardiac magnetic resonance feature tracking: a novel method to assess myocardial strain. Comparison with echocardiographic speckle tracking in healthy volunteers and in patients with left ventricular hypertrophy.

    Science.gov (United States)

    Orwat, Stefan; Kempny, Aleksander; Diller, Gerhard-Paul; Bauerschmitz, Pia; Bunck, Alexander Ch; Maintz, David; Radke, Robert M; Baumgartner, Helmut

    2014-01-01

    Left ventricular longitudinal strain (LV-LS) and strain rate (SR) are sensitive markers of early systolic dysfunction. To evaluate the feasibility of a novel, cardiac magnetic resonance (CMR) based method known as feature tracking (FT) for the assessment of strain and SR, and to compare the CMR based results to those obtained on standard transthoracic echocardiography (TTE) in healthy volunteers and in patients with left ventricular hypertrophy cardiomyopathy (HCM). Overall, 20 healthy volunteers (ten male, mean age 24 ± 3 years) and 20 consecutive patients with HCM (12 male, mean age 47 ± 19 years) were included. Longitudinal and circumferential strain and SR of the left ventricle were measured on CMR at 1.5 Tesla and TTE and interobserver variability was assessed. FT measurements were feasible in all subjects. A good agreement between global LV-LS measured on CMR (controls: 20.8 ± 3.0; HCM: 17.6 ± 3.8) and TTE (controls: 19.4 ± 2.1; HCM: 16.6 ± 2.9) was found, while the agreement was worse for circumferential strain and all SR measurements. For the left and right ventricles, interobserver reproducibility was higher for strain measurements compared to SR. Coefficients of variation were lowest for LV-LS (13.2%) by CMR. FT analysis is a novel CMR based method for the analysis of myocardial strain and SR that is simple and correlates well with the echocardiographic measurements. Since CMR is unaffected by inadequate acoustic windows, FT may represent an attractive alternative to echocardiography in assessing the increasingly important parameters of myocardial deformation.

  6. Markerless 3D Head Tracking for Motion Correction in High Resolution PET Brain Imaging

    DEFF Research Database (Denmark)

    Olesen, Oline Vinter

    relying on markers. Data-driven motion correction is problematic due to the physiological dynamics. Marker-based tracking is potentially unreliable, and it is extremely hard to validate when the tracking information is correct. The motion estimation is essential for proper motion correction of the PET...... images. Incorrect motion correction can in the worst cases result in wrong diagnosis or treatment. The evolution of a markerless custom-made structured light 3D surface tracking system is presented. The system is targeted at state-of-the-art high resolution dedicated brain PET scanners with a resolution...

  7. Storm track sensitivity to sea surface temperature resolution in a regional atmosphere model

    Energy Technology Data Exchange (ETDEWEB)

    Woollings, Tim; Blackburn, Mike [University of Reading, Department of Meteorology, Walker Institute, Earley Gate, PO Box 243, Reading (United Kingdom); National Centre for Atmospheric Science, Reading (United Kingdom); Hoskins, Brian [University of Reading, Department of Meteorology, Walker Institute, Earley Gate, PO Box 243, Reading (United Kingdom); Imperial College London, Grantham Institute, London (United Kingdom); Hassell, David [University of Reading, Met Office, Hadley Centre (Reading Unit) Meteorology Building, PO Box 243, Reading, Berkshire (United Kingdom); Hodges, Kevin [University of Reading, Environmental Systems Science Center, Reading (United Kingdom)

    2010-08-15

    A high resolution regional atmosphere model is used to investigate the sensitivity of the North Atlantic storm track to the spatial and temporal resolution of the sea surface temperature (SST) data used as a lower boundary condition. The model is run over an unusually large domain covering all of the North Atlantic and Europe, and is shown to produce a very good simulation of the observed storm track structure. The model is forced at the lateral boundaries with 15-20 years of data from the ERA-40 reanalysis, and at the lower boundary by SST data of differing resolution. The impacts of increasing spatial and temporal resolution are assessed separately, and in both cases increasing the resolution leads to subtle, but significant changes in the storm track. In some, but not all cases these changes act to reduce the small storm track biases seen in the model when it is forced with low-resolution SSTs. In addition there are several clear mesoscale responses to increased spatial SST resolution, with surface heat fluxes and convective precipitation increasing by 10-20% along the Gulf Stream SST gradient. (orig.)

  8. Track prediction of very severe cyclone 'Nargis' using high resolution ...

    Indian Academy of Sciences (India)

    In the present study, a detailed diagnostic analysis of the system 'Nargis' is carried out initially to investigate the features associated with this unusual movement and subsequently the real time forecast of VSCS 'Nargis' using high resolution advanced version weather research forecasting (WRF) model is presented.

  9. High resolution micro-pattern gaseous tracking detectors

    CERN Document Server

    Bachmann, S; Ropelewski, Leszek; Sauli, Fabio

    2000-01-01

    Micro-strip gas chambers have excellent localization properties, high rate capability and good granularity, and have been adopted for may experimental set-ups. Two recurrent problems hower have been reported: slow degradation under sustained irradiation, and damaging accidental discharges. New breeds of detectors aim at improving on these crucial points: CAT, micromegas, gas electron multiplier are examples. Very performing, they are more robust and reliable. Two- stage devices, making use of a gas electron multiplier as first element, permit to sustain larger gains in presence of high rates and heavily ionizing tracks. (16 refs).

  10. Three-dimensional Single-Track-Location Shear Wave Elasticity Imaging (STL-SWEI).

    Science.gov (United States)

    Hollender, Peter; Lipman, Samantha; Trahey, Gregg

    2017-09-06

    Conventional multiple track location shear wave elasticity imaging (MTL-SWEI) is a powerful tool for noninvasively estimating tissue elasticity. The resolution and noise levels of MTL-SWEI systems, however, are limited by ultrasound speckle. Single track location SWEI (STL-SWEI) is a novel variant which fixes the position of the tracking beam and modulates the push location to effectively cancel out the effects of speckle-induced bias. We present here a three-dimensional STL-SWEI system which provides full suppression of lateral and elevation speckle bias for high resolution volumetric elasticity imaging, and requires no spatial smoothing to make accurate measurements of shear wave speed. We demonstrate and analyze the system's performance in homogeneous and layered elasticity phantoms.

  11. Reproducibility of regional and global longitudinal strains derived from two-dimensional speckle-tracking and doppler tissue imaging between expert and novice readers during quantitative dobutamine stress echocardiography.

    Science.gov (United States)

    Yamada, Akira; Luis, Sushil A; Sathianathan, Daniel; Khandheria, Bijoy K; Cafaro, James; Hamilton-Craig, Christian R; Platts, David G; Haseler, Luke; Burstow, Darryl; Chan, Jonathan

    2014-08-01

    Longitudinal strain (LS) is a quantitative parameter that adds incremental value to wall motion analysis. The aim of this study was to compare the reproducibility of LS derived from Doppler tissue imaging and speckle-tracking between an expert and a novice strain reader during dobutamine stress echocardiography (DSE). Forty-one patients (mean age, 65 ± 15 years; mean ejection fraction, 58 ± 11%) underwent DSE per clinical protocol. Global LS derived from speckle-tracking and regional LS derived from both speckle-tracking and Doppler tissue imaging were measured twice by an expert strain reader and also measured twice by a novice strain reader. Intraobserver and interobserver analyses were performed using intraclass correlation coefficients (ICC), Bland-Altman analysis, and absolute difference values (mean ± SD). Global LS measured by the expert strain reader demonstrated high intraobserver measurement reproducibility (rest: ICC = 0.95, absolute difference = 5.5 ± 4.9%; low dose: ICC = 0.96, absolute difference = 5.7 ± 3.7%; peak dose: ICC = 0.87, absolute difference = 11.4 ± 8.4%). Global LS measured by the novice strain reader also demonstrated high intraobserver reproducibility (rest: ICC = 0.97, absolute difference = 4.1 ± 3.4%; low dose: ICC = 0.94, absolute difference = 5.4 ± 5.9%; peak dose: ICC = 0.94, absolute difference = 6.1 ± 4.8%). Global LS also showed high interobserver agreement between the expert and novice readers at all stages of DSE (rest: ICC = 0.90, absolute difference = 8.5 ± 7.5%; low dose: ICC = 0.90, absolute difference = 8.9 ± 7.1%; peak dose: ICC = 0.87, absolute difference = 10.8 ± 8.4%). Of all parameters studied, LS derived from Doppler tissue imaging had relatively low interobserver and intraobserver agreement. Global LS is highly reproducible during all stages of DSE. This variable is a potentially reliable and reproducible measure of myocardial deformation. Copyright © 2014 American Society of Echocardiography

  12. High Resolution Tracking Devices Based on Capillaries Filled with Liquid Scintillator

    CERN Multimedia

    Bonekamper, D; Vassiltchenko, V; Wolff, T

    2002-01-01

    %RD46 %title\\\\ \\\\The aim of the project is to develop high resolution tracking devices based on thin glass capillary arrays filled with liquid scintillator. This technique provides high hit densities and a position resolution better than 20 $\\mu$m. Further, their radiation hardness makes them superior to other types of tracking devices with comparable performance. Therefore, the technique is attractive for inner tracking in collider experiments, microvertex devices, or active targets for short-lived particle detection. High integration levels in the read-out based on the use of multi-pixel photon detectors and the possibility of optical multiplexing allow to reduce considerably the number of output channels, and, thus, the cost for the detector.\\\\ \\\\New optoelectronic devices have been developed and tested: the megapixel Electron Bombarded CCD (EBCCD), a high resolution image-detector having an outstanding capability of single photo-electron detection; the Vacuum Image Pipeline (VIP), a high-speed gateable pi...

  13. Analysis of laser speckle patterns from fingertips

    DEFF Research Database (Denmark)

    Iversen, Theis Faber Quist; Hanson, Steen Grüner

    2010-01-01

    from mobile phones to laptops and PDA´s. However, the dynamics of scattered light from live tissue must be taken into account when designing optical sensor systems for tracking e.g. fingertips in touch-applications. Especially, when using coherent light sources, the statistics of the speckle...

  14. Left ventricular longitudinal strain measured by speckle tracking as a predictor of the decrease in left ventricular deformation in children with congenital stenosis of the aorta or coarctation of the aorta.

    Science.gov (United States)

    Van der Ende, J; Vázquez Antona, Clara A; Erdmenger Orellana, Julio; Romero Cárdenas, Ángel; Roldan, Francisco Javier; Vargas Barrón, Jesús

    2013-07-01

    Children born with a left ventricular outflow tract obstruction (LVOTO) can present with symptoms of left ventricular (LV) failure while ejection fraction (EF) is normal. A more sensitive parameter of systolic function might be obtained with speckle tracking echocardiography, which describes ventricular longitudinal deformation in strain values. It is presumed that despite a normal or only slight decrease in ejection fraction, patients with a LVOTO demonstrate aberrations in the longitudinal deformation of the left ventricle. In addition, it is expected that after a successful intervention, longitudinal deformation returns to normal values. Standard trans-thoracic echocardiography was performed on 33 consecutive patients with a LVOTO, either an isolated aortic coarctation (AoCo) or an isolated aortic stenosis (AoSt). Before intervention a significant decrease in strain values was observed compared with the control group (N = 40), with an additional decrease in strain values in the first week after intervention (N = 16). Strain values recovered after a mean follow-up period of 42 wk (N = 9), though normal values were never reached. In addition, patients with an AoCo had a smaller decrease in strain values compared with patients with AoSt. All strain values were measured with a concomitant ejection fraction between normal limits. It is concluded that patients with a congenital LVOTO have decreased ventricular systolic function measured as strain values, whereas their ejection fraction is within the normal range. Therefore, as ejection fraction may not be an accurate measure, speckle tracking-based strain may be significant in the identification of subtle changes in longitudinal deformation and may create opportunities for patients to benefit from early treatment for heart failure. Copyright © 2013 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  15. A simple and rapid method for high-resolution visualization of single-ion tracks

    Energy Technology Data Exchange (ETDEWEB)

    Omichi, Masaaki [Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Osaka 565-0871 (Japan); Center for Collaborative Research, Anan National College of Technology, Anan, Tokushima 774-0017 (Japan); Choi, Wookjin; Sakamaki, Daisuke; Seki, Shu, E-mail: seki@chem.eng.osaka-u.ac.jp [Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Osaka 565-0871 (Japan); Tsukuda, Satoshi [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Miyagi 980-8577 (Japan); Sugimoto, Masaki [Japan Atomic Energy Agency, Takasaki Advanced Radiation Research Institute, Gunma, Gunma 370-1292 (Japan)

    2014-11-15

    Prompt determination of spatial points of single-ion tracks plays a key role in high-energy particle induced-cancer therapy and gene/plant mutations. In this study, a simple method for the high-resolution visualization of single-ion tracks without etching was developed through the use of polyacrylic acid (PAA)-N, N’-methylene bisacrylamide (MBAAm) blend films. One of the steps of the proposed method includes exposure of the irradiated films to water vapor for several minutes. Water vapor was found to promote the cross-linking reaction of PAA and MBAAm to form a bulky cross-linked structure; the ion-track scars were detectable at a nanometer scale by atomic force microscopy. This study demonstrated that each scar is easily distinguishable, and the amount of generated radicals of the ion tracks can be estimated by measuring the height of the scars, even in highly dense ion tracks. This method is suitable for the visualization of the penumbra region in a single-ion track with a high spatial resolution of 50 nm, which is sufficiently small to confirm that a single ion hits a cell nucleus with a size ranging between 5 and 20 μm.

  16. A simple and rapid method for high-resolution visualization of single-ion tracks

    Directory of Open Access Journals (Sweden)

    Masaaki Omichi

    2014-11-01

    Full Text Available Prompt determination of spatial points of single-ion tracks plays a key role in high-energy particle induced-cancer therapy and gene/plant mutations. In this study, a simple method for the high-resolution visualization of single-ion tracks without etching was developed through the use of polyacrylic acid (PAA-N, N’-methylene bisacrylamide (MBAAm blend films. One of the steps of the proposed method includes exposure of the irradiated films to water vapor for several minutes. Water vapor was found to promote the cross-linking reaction of PAA and MBAAm to form a bulky cross-linked structure; the ion-track scars were detectable at a nanometer scale by atomic force microscopy. This study demonstrated that each scar is easily distinguishable, and the amount of generated radicals of the ion tracks can be estimated by measuring the height of the scars, even in highly dense ion tracks. This method is suitable for the visualization of the penumbra region in a single-ion track with a high spatial resolution of 50 nm, which is sufficiently small to confirm that a single ion hits a cell nucleus with a size ranging between 5 and 20 μm.

  17. A fast high resolution track trigger for the H1 experiment

    CERN Document Server

    Baird, A; Fleming, Y H; Kolander, M; Kolya, S; Meer, D; Mercer, D; Naumann, J; Newman, P R; Sankey, D; Schöning, A; Schultz-Coulon, H C; Wissing, C

    2000-01-01

    After 2001 the upgraded ep collider HERA will provide an about five times higher luminosity for the iwo experiments Hl and ZEUS. In order to cope with the expected higher event rates the Hl collaboration is building a track based trigger system, the Fast Track Trigger (FTT). It will be integrated in the first three levels (L1-L3) of the Hl trigger scheme to provide higher selectivity for events with charged particles. The FTT will allow to reconstruct 3-dimensional tracks in the central drift chamber down to 100 MeV/c within the L2 latency of similar to 23 mus. To reach the necessary momentum resolution of similar to 5% (at 1 GeV/c) sophisticated reconstruction algorithms have to be implemented using high density Field Programmable Gate Arrays (FPGA) and their embedded Content Addressable Memories (CAM). The final track parameter optimization will be done using non- iterative fits implemented in DSPs. While at the first trigger level rough track information will be provided, at L2 tracks with high resolution ...

  18. Fine tuning of track impact parameter resolution of the DELPHI detector

    CERN Document Server

    Borisov, G

    1996-01-01

    The fine tuning of the charged track impact parameter resolution for data and simulation in the DELPHI detector at LEP is described. This tuning was implemented in the software for the tagging of $B$ hadrons and has been applied in many precise measurements.

  19. Shear wave arrival time estimates correlate with local speckle pattern.

    Science.gov (United States)

    Mcaleavey, Stephen A; Osapoetra, Laurentius O; Langdon, Jonathan

    2015-12-01

    We present simulation and phantom studies demonstrating a strong correlation between errors in shear wave arrival time estimates and the lateral position of the local speckle pattern in targets with fully developed speckle. We hypothesize that the observed arrival time variations are largely due to the underlying speckle pattern, and call the effect speckle bias. Arrival time estimation is a key step in quantitative shear wave elastography, performed by tracking tissue motion via cross-correlation of RF ultrasound echoes or similar methods. Variations in scatterer strength and interference of echoes from scatterers within the tracking beam result in an echo that does not necessarily describe the average motion within the beam, but one favoring areas of constructive interference and strong scattering. A swept-receive image, formed by fixing the transmit beam and sweeping the receive aperture over the region of interest, is used to estimate the local speckle pattern. Metrics for the lateral position of the speckle are found to correlate strongly (r > 0.7) with the estimated shear wave arrival times both in simulations and in phantoms. Lateral weighting of the swept-receive pattern improved the correlation between arrival time estimates and speckle position. The simulations indicate that high RF echo correlation does not equate to an accurate shear wave arrival time estimate-a high correlation coefficient indicates that motion is being tracked with high precision, but the location tracked is uncertain within the tracking beam width. The presence of a strong on-axis speckle is seen to imply high RF correlation and low bias. The converse does not appear to be true-highly correlated RF echoes can still produce biased arrival time estimates. The shear wave arrival time bias is relatively stable with variations in shear wave amplitude and sign (-20 μm to 20 μm simulated) compared with the variation with different speckle realizations obtained along a given tracking

  20. High-resolution cell outline segmentation and tracking from phase-contrast microscopy images

    OpenAIRE

    Ambühl, Mark; Brepsant, C.; Meister, Jean-Jacques; Verkhovsky, Alexander; Sbalzarini, I. F.

    2012-01-01

    Accurate extraction of cell outlines from microscopy images is essential for analysing the dynamics of migrating cells. Phase-contrast microscopy is one of the most common and convenient imaging modalities for observing cell motility because it does not require exogenous labelling and uses only moderate light levels with generally negligible phototoxicity effects. Automatic extraction and tracking of high-resolution cell outlines from phase-contrast images, however, is difficult due to comple...

  1. Automated measurement of resolution acuity in infants using remote eye-tracking.

    Science.gov (United States)

    Jones, Pete R; Kalwarowsky, Sarah; Atkinson, Janette; Braddick, Oliver J; Nardini, Marko

    2014-10-28

    To validate a novel, automated test of infant resolution acuity based on remote eye-tracking. Infants aged 2 to 12 months were tested binocularly using a new adaptive computerized test of infant vision using eye tracking (ACTIVE), and Keeler infant acuity cards (KIAC). The ACTIVE test ran automatically, using remote eye-tracking to assess whether the infant fixated a black-and-white grating of variable spatial frequency. Test-retest reliability was assessed by performing each test twice. Accuracy was assessed by comparing acuity measures across tests and with established age-norms, and by comparing low-contrast acuity estimates in adults with data reported previously. All infants completed the ACTIVE test at least once. Median test duration was 101 seconds. Measured visual acuity increased with age (P 0.183). An adaptive computerized test of infant vision using eye-tracking provides a rapid, automated measure of resolution acuity in preverbal infants. The ACTIVE performed comparably to the current clinical gold standard (acuity cards) in terms of testability, reliability, and accuracy, and its principles can be extended to measure other visual functions. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

  2. Kitt Peak speckle camera.

    Science.gov (United States)

    Breckinridge, J B; McAlister, H A; Robinson, W G

    1979-04-01

    The speckle camera in regular use at Kitt Peak National Observatory since 1974 is described in detail. The design of the atmospheric dispersion compensation prisms, the use of film as a recording medium, the accuracy of double star measurements, and the next generation speckle camera are discussed. Photographs of double star speckle patterns with separations from 1.4 sec of arc to 4.7 sec of arc are shown to illustrate the quality of image formation with this camera, the effects of seeing on the patterns, and to illustrate the isoplanatic patch of the atmosphere.

  3. High resolution three-dimensional robotic synthetic tracked aperture ultrasound imaging: feasibility study

    Science.gov (United States)

    Zhang, Haichong K.; Fang, Ting Yun; Finocchi, Rodolfo; Boctor, Emad M.

    2017-03-01

    Three dimensional (3D) ultrasound imaging is becoming a standard mode for medical ultrasound diagnoses. Conventional 3D ultrasound imaging is mostly scanned either by using a two dimensional matrix array or by motorizing a one dimensional array in the elevation direction. However, the former system is not widely assessable due to its cost, and the latter one has limited resolution and field-of-view in the elevation axis. Here, we propose a 3D ultrasound imaging system based on the synthetic tracked aperture approach, in which a robotic arm is used to provide accurate tracking and motion. While the ultrasound probe is moved by a robotic arm, each probe position is tracked and can be used to reconstruct a wider field-of-view as there are no physical barriers that restrict the elevational scanning. At the same time, synthetic aperture beamforming provides a better resolution in the elevation axis. To synthesize the elevational information, the single focal point is regarded as the virtual element, and forward and backward delay-andsum are applied to the radio-frequency (RF) data collected through the volume. The concept is experimentally validated using a general ultrasound phantom, and the elevational resolution improvement of 2.54 and 2.13 times was measured at the target depths of 20 mm and 110 mm, respectively.

  4. Relationship between two-dimensional speckle-tracking septal strain and response to cardiac resynchronization therapy in patients with left ventricular dysfunction and left bundle branch block: a prospective pilot study.

    Science.gov (United States)

    Maréchaux, Sylvestre; Guiot, Aurélie; Castel, Anne Laure; Guyomar, Yves; Semichon, Marc; Delelis, François; Heuls, Sebastien; Ennezat, Pierre-Vladimir; Graux, Pierre; Tribouilloy, Christophe

    2014-05-01

    Previous studies have demonstrated variable patterns of longitudinal septal deformation in patients with left ventricular (LV) dysfunction and left bundle branch block. This prospective single center study was designed to assess the relationship between septal deformation patterns obtained by two-dimensional speckle-tracking echocardiography and response to cardiac resynchronization therapy (CRT). One hundred one patients with New York Heart Association class II to IV heart failure, LV ejection fractions ≤ 35%, and left bundle branch block underwent echocardiography before CRT. Longitudinal two-dimensional speckle-tracking strain analysis in the apical four-chamber view identified three patterns: double-peaked systolic shortening (pattern 1), early pre-ejection shortening peak followed by prominent systolic stretch (pattern 2), and pseudonormal shortening with a late systolic shortening peak and less pronounced end-systolic stretch (pattern 3). CRT response was defined as a relative reduction in LV end-systolic volume of ≥ 15% at 9-month follow-up. CRT super-response was defined as an absolute LV ejection fraction of ≥ 50% associated with a relative reduction in LV end-systolic volume of ≥ 15% and an improvement in New York Heart Association functional class. Cardiac death or hospitalization for heart failure during follow-up was systematically investigated. Ninety-two percent of patients with pattern 1 or 2 were responders to CRT compared with 59% with pattern 3 (P < .0001). Thirty-six percent of patients with pattern 1 were super-responders compared with 15% of those with pattern 2 and 12% of those with pattern 3 (P = .037). The improvement in LV volumes, LV ejection fraction, and global longitudinal strain after CRT was better in patients with pattern 1 or 2 compared with those with pattern 3 (P < .0001 for all). Eighteen-month outcomes were excellent in patients with pattern 1 or 2, with event-free survival of 95 ± 3% compared with 75 ± 7% in patients

  5. High-resolution robot tracking and direction finding for space station environment

    Science.gov (United States)

    Shahrabi, Kamal

    1993-03-01

    In the past few years the problem of location finding and tracking of extravehicular robots in space station environment, and the related problem of estimating the parameters of signals in noise, have attracted considerable interest. Conventional direction finding, tracking, and locating techniques such as maximum likelihood (ML) and multiple signal characterization (MUSIC) are proving inadequate to support the full and effective utilization of robotics in a space station environment. The scope of this work is to provide a new and more efficient signal processing technique for a space station robotic tracking system which overcomes existing technical limitations such as radio transmission multipath, station reflections, the number of robots, space station environment, stringent resolution requirements, and space station architecture. In general, this work contains block level design and study of a communication system for a space station involving spread spectrum and digital processing of signal techniques that achieves as space station robotic tracking implementation. This report contains an extensive analysis of the system performance from the following points of view: utilization of a chirp signal, which, in conjunction with a polling procedure, allows for individual robot identification, location and tracking; estimate the number of antennae; determine the location of the antennae on the space station; generate a detailed block diagram design; and perform an overall system analysis that considers the effects of signal multipath.

  6. Speckle reducing anisotropic diffusion.

    Science.gov (United States)

    Yu, Yongjian; Acton, Scott T

    2002-01-01

    This paper provides the derivation of speckle reducing anisotropic diffusion (SRAD), a diffusion method tailored to ultrasonic and radar imaging applications. SRAD is the edge-sensitive diffusion for speckled images, in the same way that conventional anisotropic diffusion is the edge-sensitive diffusion for images corrupted with additive noise. We first show that the Lee and Frost filters can be cast as partial differential equations, and then we derive SRAD by allowing edge-sensitive anisotropic diffusion within this context. Just as the Lee and Frost filters utilize the coefficient of variation in adaptive filtering, SRAD exploits the instantaneous coefficient of variation, which is shown to be a function of the local gradient magnitude and Laplacian operators. We validate the new algorithm using both synthetic and real linear scan ultrasonic imagery of the carotid artery. We also demonstrate the algorithm performance with real SAR data. The performance measures obtained by means of computer simulation of carotid artery images are compared with three existing speckle reduction schemes. In the presence of speckle noise, speckle reducing anisotropic diffusion excels over the traditional speckle removal filters and over the conventional anisotropic diffusion method in terms of mean preservation, variance reduction, and edge localization.

  7. Pedestrian Detection and Tracking from Low-Resolution Unmanned Aerial Vehicle Thermal Imagery

    Directory of Open Access Journals (Sweden)

    Yalong Ma

    2016-03-01

    Full Text Available Driven by the prominent thermal signature of humans and following the growing availability of unmanned aerial vehicles (UAVs, more and more research efforts have been focusing on the detection and tracking of pedestrians using thermal infrared images recorded from UAVs. However, pedestrian detection and tracking from the thermal images obtained from UAVs pose many challenges due to the low-resolution of imagery, platform motion, image instability and the relatively small size of the objects. This research tackles these challenges by proposing a pedestrian detection and tracking system. A two-stage blob-based approach is first developed for pedestrian detection. This approach first extracts pedestrian blobs using the regional gradient feature and geometric constraints filtering and then classifies the detected blobs by using a linear Support Vector Machine (SVM with a hybrid descriptor, which sophisticatedly combines Histogram of Oriented Gradient (HOG and Discrete Cosine Transform (DCT features in order to achieve accurate detection. This research further proposes an approach for pedestrian tracking. This approach employs the feature tracker with the update of detected pedestrian location to track pedestrian objects from the registered videos and extracts the motion trajectory data. The proposed detection and tracking approaches have been evaluated by multiple different datasets, and the results illustrate the effectiveness of the proposed methods. This research is expected to significantly benefit many transportation applications, such as the multimodal traffic performance measure, pedestrian behavior study and pedestrian-vehicle crash analysis. Future work will focus on using fused thermal and visual images to further improve the detection efficiency and effectiveness.

  8. Pedestrian Detection and Tracking from Low-Resolution Unmanned Aerial Vehicle Thermal Imagery

    Science.gov (United States)

    Ma, Yalong; Wu, Xinkai; Yu, Guizhen; Xu, Yongzheng; Wang, Yunpeng

    2016-01-01

    Driven by the prominent thermal signature of humans and following the growing availability of unmanned aerial vehicles (UAVs), more and more research efforts have been focusing on the detection and tracking of pedestrians using thermal infrared images recorded from UAVs. However, pedestrian detection and tracking from the thermal images obtained from UAVs pose many challenges due to the low-resolution of imagery, platform motion, image instability and the relatively small size of the objects. This research tackles these challenges by proposing a pedestrian detection and tracking system. A two-stage blob-based approach is first developed for pedestrian detection. This approach first extracts pedestrian blobs using the regional gradient feature and geometric constraints filtering and then classifies the detected blobs by using a linear Support Vector Machine (SVM) with a hybrid descriptor, which sophisticatedly combines Histogram of Oriented Gradient (HOG) and Discrete Cosine Transform (DCT) features in order to achieve accurate detection. This research further proposes an approach for pedestrian tracking. This approach employs the feature tracker with the update of detected pedestrian location to track pedestrian objects from the registered videos and extracts the motion trajectory data. The proposed detection and tracking approaches have been evaluated by multiple different datasets, and the results illustrate the effectiveness of the proposed methods. This research is expected to significantly benefit many transportation applications, such as the multimodal traffic performance measure, pedestrian behavior study and pedestrian-vehicle crash analysis. Future work will focus on using fused thermal and visual images to further improve the detection efficiency and effectiveness. PMID:27023564

  9. High-resolution tracking using large capillary bundles filled with liquid scintillator

    CERN Document Server

    Annis, P; Benussi, L; Bruski, N; Buontempo, S; Currat, C; D'Ambrosio, N; Van Dantzig, R; Dupraz, J P; Ereditato, A; Fabre, Jean-Paul; Fanti, V; Feyt, J; Frekers, D; Frenkel, A; Galeazzi, F; Garufi, F; Goldberg, J; Golovkin, S V; Gorin, A M; Grégoire, G; Harrison, K; Höpfner, K; Holtz, K; Konijn, J; Kozarenko, E N; Kreslo, I E; Kushnirenko, A E; Liberti, B; Martellotti, G; Medvedkov, A M; Michel, L; Migliozzi, P; Mommaert, C; Mondardini, M R; Panman, J; Penso, G; Petukhov, Yu P; Rondeshagen, D; Siegmund, W P; Tyukov, V E; Van Beek, G; Vasilchenko, V G; Vilain, P; Visschers, J L; Wilquet, G; Winter, Klaus; Wolff, T; Wörtche, H J; Wong, H; Zimyn, K V

    2000-01-01

    We have developed large high-resolution tracking detectors based on glass capillaries filled with organic liquid scintillator of high refractive index. These liquid-core scintillating optical fibres act simultaneously as detectors of charged particles and as image guides. Track images projected onto the readout end of a capillary bundle are visualized by an optoelectronic chain consisting of a set of image-intensifier tubes followed by a photosensitive CCD or by an EBCCD camera. Two prototype detectors, each composed of \\hbox{$\\approx 10^6$} capillaries with \\hbox{20$-$25 $\\mu$m} diameter and \\hbox{0.9$-$1.8 m} length, have been tested, and a spatial resolution of the order of \\hbox{20$-$40 $\\mu$m} has been attained. A high scintillation efficiency and a large light-attenuation length, in excess of 3 m, was achieved through special purification of the liquid scintillator. Along the tracks of minimum-ionizing particles, the hit densities obtained were $\\sim$ 8 hits/mm at the readout window, and \\hbox{$\\sim$ 3 ...

  10. Right heart function in impaired left ventricular diastolic function: 2D speckle tracking echocardiography-based and Doppler tissue imaging-based analysis of right atrial and ventricular function.

    Science.gov (United States)

    Brand, Anna; Bathe, Marny; Oertelt-Prigione, Sabine; Seeland, Ute; Rücke, Mirjam; Regitz-Zagrosek, Vera; Stangl, Karl; Knebel, Fabian; Stangl, Verena; Dreger, Henryk

    2018-01-01

    The aim of our study was to describe right atrial (RA) and right ventricular (RV) function, assessed by Doppler tissue imaging and 2D speckle tracking echocardiography (2DSTE), in women with signs of early impaired left ventricular diastolic function (DD). In a cross-sectional trial, standard parameters of diastolic and right heart function were investigated in 438 women of the Berlin Female Risk Evaluation (BEFRI) study. In a subset of women, average peak systolic RA strain (RAS), as well as the average peak systolic RV strain of the free wall (RVS free wall) and of all RV segments (average RV strain; RVS Avg), was analyzed using 2DSTE. Compared to women with normal diastolic function (DD0), RAS, RVS free wall and RVS Avg were significantly reduced in DD (43.1% ± 11.9%, -26.7% ± 5.6%, and -23.3% ± 3.5% in DD0; vs 35.1% ± 10.4%, -23.9% ± 5.5%, and -20.6% ± 3.8% in DD; P right heart function is significantly altered in DD. DTI as well as 2DSTE constitute sensitive echocardiographic tools that enable the diagnosis of impaired right heart mechanics in early-staged DD. © 2017 Wiley Periodicals, Inc.

  11. The impact of hypertension as a road to heart failure with preserved ejection fraction: diagnostic value of two-dimensional speckle tracking echocardiography for the early impairment of left atrial-left ventricular-arterial coupling.

    Science.gov (United States)

    Oki, Takashi; Miyoshi, Hirokazu; Oishi, Yoshifumi; Mizuguchi, Yukio; Ara, Nusrat; Iuchi, Arata

    2014-01-01

    Heart failure with preserved ejection fraction (HFPEF) is a syndrome that frequently occurs in older people and patients with cardiovascular risk factors, particularly hypertension. This syndrome is not a specific disease process, whereas is associated with high morbidity and mortality in patients with heart failure with reduced ejection fraction (HFREF) as well. Therefore, a "one size fits all" diagnosis strategy is unlikely to operate for patients with HFPEF. Assessment of left atrial (LA)-left ventricular (LV)-arterial coupling seems to have a clinical impact on hypertensive patients, because HF signs and symptoms have been found to be significantly related to inappropriate LA-LV interaction during diastole and LV-arterial interaction during systole. Two-dimensional speckle tracking echocardiography (2DSTE) is a new tool that may have a role in earlier detecting the impaired LA, LV, and arterial function in asymptomatic patients. This review explored the impact of LA-LV-arterial coupling in understanding the pathophysiology of hypertension as a road to HFPEF, and the possibilities of clinical application by using 2DSTE.

  12. Left ventricular rigid body rotation in a diffuse large B-cell lymphoma patient with cardiac involvement: A case from the three-dimensional speckle-tracking echocardiographic MAGYAR-Path Study.

    Science.gov (United States)

    Földeák, Dóra; Kalapos, Anita; Domsik, Péter; Sinkó, Mária; Szeleczki, Nóra; Bagdi, Enikő; Krenács, László; Forster, Tamás; Borbényi, Zita; Nemes, Attila

    2017-02-01

    Secondary myocardial involvement by diffuse large B-cell lymphoma is a rare occurrence. Left ventricular (LV) twist is considered an essential part of LV function. In normal circumstances LV twist results from the movement of two orthogonally oriented muscular bands of a helical myocardial structure with consequent clockwise rotation of the base and counterclockwise rotation of the apex. Three-dimensional (3D) speckle-tracking echocardiography (3DSTE) has been found to be feasible for non-invasive 3D quantification of LV wall motion and rotational mechanics. The present report aimed to assess LV twisting motion in a patient with diffuse large B-cell lymphoma with positron emission tomography/computer tomography-proven cardiac involvement by 3DSTE. During 3DSTE, reduction in some segmental radial, longitudinal, circumferential, area and 3D LV strains were found. Apical and basal LV rotations were found to be in the same counterclockwise direction, confirming near absence of LV twist - so-called rigid body rotation. Copyright © 2016 Sociedade Portuguesa de Cardiologia. Publicado por Elsevier España, S.L.U. All rights reserved.

  13. A high-resolution tracking hodoscope based on capillary layers filled with liquid scintillator

    CERN Document Server

    Bay, A; Bruski, N; Buontempo, S; Currat, C; D'Ambrosio, N; Ekimov, A V; Ereditato, A; Fabre, Jean-Paul; Fanti, V; Frekers, D; Frenkel, A; Golovkin, S V; Govorun, V N; Harrison, K; Koppenburg, P; Kozarenko, E N; Kreslo, I E; Liberti, B; Martellotti, G; Medvedkov, A M; Mondardini, M R; Penso, G; Siegmund, W P; Vasilchenko, V G; Vilain, P; Wilquet, G; Winter, Klaus; Wörtche, H J

    2001-01-01

    Results are given on tests of a high-resolution tracking hodoscope based on layers of \\hbox{26-$\\mu$m-bore} glass capillaries filled with organic liquid scintillator (1-methylnaphthalene doped with R39). The detector prototype consisted of three 2-mm-thick parallel layers, with surface areas of $2.1 \\times 21$~cm$^2$. The layers had a centre-to-centre spacing of 6~mm, and were read by an optoelectronic chain comprising two electrostatically focused image intensifiers and an Electron-Bombarded Charge-Coupled Device (EBCCD). Tracks of cosmic-ray particles were recorded and analysed. The observed hit density was 6.6~hits/mm for particles crossing the layers perpendicularly, at a distance of 1~cm from the capillaries' readout end, and 4.2~hits/mm for particles at a distance of 20~cm. A track segment reconstructed in a single layer had an rms residual of $\\sim$~20~$\\mu$m, and allowed determination of the track position in a neighbouring layer with a precision of $\\sim$~170~$\\mu$m. This latter value corresponded to...

  14. Enhanced Video Surveillance (EVS) with speckle imaging

    Energy Technology Data Exchange (ETDEWEB)

    Carrano, C J

    2004-01-13

    Enhanced Video Surveillance (EVS) with Speckle Imaging is a high-resolution imaging system that substantially improves resolution and contrast in images acquired over long distances. This technology will increase image resolution up to an order of magnitude or greater for video surveillance systems. The system's hardware components are all commercially available and consist of a telescope or large-aperture lens assembly, a high-performance digital camera, and a personal computer. The system's software, developed at LLNL, extends standard speckle-image-processing methods (used in the astronomical community) to solve the atmospheric blurring problem associated with imaging over medium to long distances (hundreds of meters to tens of kilometers) through horizontal or slant-path turbulence. This novel imaging technology will not only enhance national security but also will benefit law enforcement, security contractors, and any private or public entity that uses video surveillance to protect their assets.

  15. A novel approach to study radiation track structure with nanometer-equivalent resolution

    Science.gov (United States)

    Casiraghi, Margherita; Bashkirov, Vladimir; Hurley, Ford; Schulte, Reinhard

    2014-05-01

    Clustered DNA damages are considered the critical lesions in the pathways leading from the initial energy deposition by radiation to radiobiological damage. The spatial distribution of the initial DNA damage is mainly determined by radiation track-structure at the nanometer level. In this work, a novel experimental approach to image the three-dimensional structure of micrometric radiation track segments is presented. The approach utilizes the detection of single ions created in low-pressure gas. Ions produced by radiation drift towards a GEM-like 2D hole-pattern detector. When entering individual holes, ions can induce ion-impact ionization of the working-gas starting a confined electron avalanche that generates the output signal. By registering positive ions rather than electrons, diffusion is reduced and a spatial resolution of the track image of the order of water-equivalent nanometers can be achieved. Measurements and simulations to characterize the performance of a few detector designs were performed. Different cathode materials were tested and ionization cluster size distributions of 241Am alpha particles were measured. The electric field configuration in the detector was calculated to optimize the ion focusing into the detector holes. The preliminary results obtained show the directions for further development of the detector. Contribution to the Topical Issue "Nano-scale Insights into Ion-beam Cancer Therapy", edited by Andrey V. Solov'yov, Nigel Mason, Paulo Limão-Vieira and Malgorzata Smialek-Telega

  16. "Mtrack 2.0": An ultra-scale tracking algorithm for low-resolution overhead imagery

    Energy Technology Data Exchange (ETDEWEB)

    Carrano, C J

    2008-09-26

    Overhead persistent surveillance systems are becoming more capable at acquiring wide-field image sequences for long time-spans. The need to exploit this data is becoming ever greater. The ability to track a single vehicle of interest or to track all the observable vehicles, which may number in the thousands, over large, cluttered regions while they persist in the imagery is very desirable. Typically, this imagery has many thousands of pixels on a side and is characterized by lower resolutions (e.g. {approx}0.5 meters/pixel to {approx}2.0 meters/pixel) and lower frame rates (e.g. {approx} sub-Hz to several Hz). We describe our ultra-scale capable implementation of a multiple-vehicle tracking algorithm for overhead persistent surveillance imagery. This work builds upon an earlier report, where now the algorithm has been modified for improved performance and has been substantially improved to handle much larger datasets in a much shorter time.

  17. Real time micro/nano particle detection and tracking with nanosecond resolution

    Science.gov (United States)

    Qian, Feng; Song, Qi; Tien, En-kuang; Boyraz, Ozdal

    2009-08-01

    Real-time optical imaging and tracking of particles in a complex environment to understand coordinated events has attracted researchers from various areas such as biomechanics. Here, we report a way for real time detection and tracking of micron size particles in time-space-wavelength mapping technology by using a single detector. Experimentally, we demonstrate real time tracking of micron size glass particles with 50ns temporal resolution and fiber laser to emit 50nm short pulses at 1550nm. Following a dispersive time wavelength mapping in a chirped fiber grating and space-time-wavelength mapping through a diffraction grating with 600lines/mm, we generate an elliptical beam where each wavelength component corresponds to different time and position in space. Then the generated beam is focused on an image plane by using 20X-40X microscope objectives. The presence of particles on the image plane induces amplitude modulation on each pulse which is captured in real time by a high speed digitizing oscilloscope with 20GS/s sampling rate. The trajectory of the particle is extracted from the dynamic amplitude modulation in a post processing. The same system has also been utilized for imaging of particles by using one dimensional scanning.

  18. Influence of Speckle Filtering on Polarimetric SAR Data Classification

    Science.gov (United States)

    Shitole, Sanjay; Rao, Y. S.; Mohan, B. Krishna

    2013-08-01

    PolSAR data without speckle reduction provide insufficient accuracy for the segmentation and classification. Fully Polarimetric ALOS PALSAR and Radarsat-2 data acquired over Mumbai, India are used to test the effect of speckle filtering on the classification. Wishart supervised classifier algorithm is used for classification of the filtered and unfiltered data. Boxcar, Refined Lee, Lopez, IDAN, Improved Sigma and newly introduced Sequential Filter are analysed for improvement of classification accuracy. Selection of the most suitable moving window size of speckle reducing algorithms is an important step during speckle filtering. Boxcar and Refined Lee filters are used to test the effect of speckle filtering on classification with varying moving window size of the filter. Boxcar filter has a good noise smoothing capability. Speckle in the image can be minimized by increasing size of scanning window in the process of speckle reduction. However, this undiscriminating averaging using Boxcar filter causes a resolution loss in the vicinity of sharp edges and point targets in the image. As the edges in the image need to be maintained, well known Kohonens Self-Organizing Feature Map (SOFM) is used for this purpose.

  19. Comparison of different "along the track" high resolution satellite stereo-pair for DSM extraction

    Science.gov (United States)

    Nikolakopoulos, Konstantinos G.

    2013-10-01

    The possibility to create DEM from stereo pairs is based on the Pythagoras theorem and on the principles of photogrammetry that are applied to aerial photographs stereo pairs for the last seventy years. The application of these principles to digital satellite stereo data was inherent in the first satellite missions. During the last decades the satellite stereo-pairs were acquired across the track in different days (SPOT, ERS etc.). More recently the same-date along the track stereo-data acquisition seems to prevail (Terra ASTER, SPOT5 HRS, Cartosat, ALOS Prism) as it reduces the radiometric image variations (refractive effects, sun illumination, temporal changes) and thus increases the correlation success rate in any image matching.Two of the newest satellite sensors with stereo collection capability is Cartosat and ALOS Prism. Both of them acquire stereopairs along the track with a 2,5m spatial resolution covering areas of 30X30km. In this study we compare two different satellite stereo-pair collected along the track for DSM creation. The first one is created from a Cartosat stereopair and the second one from an ALOS PRISM triplet. The area of study is situated in Chalkidiki Peninsula, Greece. Both DEMs were created using the same ground control points collected with a Differential GPS. After a first control for random or systematic errors a statistical analysis was done. Points of certified elevation have been used to estimate the accuracy of these two DSMs. The elevation difference between the different DEMs was calculated. 2D RMSE, correlation and the percentile value were also computed and the results are presented.

  20. Reducing Earth Topography Resolution for SMAP Mission Ground Tracks Using K-Means Clustering

    Science.gov (United States)

    Rizvi, Farheen

    2013-01-01

    The K-means clustering algorithm is used to reduce Earth topography resolution for the SMAP mission ground tracks. As SMAP propagates in orbit, knowledge of the radar antenna footprints on Earth is required for the antenna misalignment calibration. Each antenna footprint contains a latitude and longitude location pair on the Earth surface. There are 400 pairs in one data set for the calibration model. It is computationally expensive to calculate corresponding Earth elevation for these data pairs. Thus, the antenna footprint resolution is reduced. Similar topographical data pairs are grouped together with the K-means clustering algorithm. The resolution is reduced to the mean of each topographical cluster called the cluster centroid. The corresponding Earth elevation for each cluster centroid is assigned to the entire group. Results show that 400 data points are reduced to 60 while still maintaining algorithm performance and computational efficiency. In this work, sensitivity analysis is also performed to show a trade-off between algorithm performance versus computational efficiency as the number of cluster centroids and algorithm iterations are increased.

  1. Speckle-Free Coherence Tomography of Turbid Media

    CERN Document Server

    Liba, Orly; SoRelle, Elliott D; Dutta, Rebecca; Sen, Debasish; Moshfeghi, Darius M; Chu, Steven; de la Zerda, Adam

    2016-01-01

    Optical coherence tomography (OCT) is a powerful biomedical imaging technology that relies on the coherent detection of backscattered light to image tissue morphology in vivo. As a consequence, OCT is susceptible to coherent noise (speckle noise), which imposes significant limitations on its diagnostic capabilities. Here we show a method based purely on light manipulation that is able to entirely remove the speckle noise originating from turbid samples without any compromise in resolution. We refer to this method as Speckle-Free OCT (SFOCT). Using SFOCT, we succeeded in revealing small structures that are otherwise hidden by speckle noise when using conventional OCT, including the inner stromal structure of a live mouse cornea, the fine structures inside the mouse pinna, sweat ducts, and Meissners corpuscle in the human fingertip skin. SFOCT has the potential to markedly increase OCTs diagnostic capabilities of various human diseases by revealing minute features that correlate with early pathology.

  2. Particle-Tracking within an Ultra-High-Resolution Urban Domain Integrated with Best Management Practices

    Science.gov (United States)

    Lopez, S. R.; Maxwell, R. M.

    2014-12-01

    Best management practices (BMPs) are used to offset the impacts of urban developments known to decrease aquifer recharge, alter drainage networks, change feedbacks to the atmosphere and enhance contaminant transport. To evaluate the effectiveness of BMPs (i.e. engineered wetlands, grass swales, permeable pavements, etc.), a high-resolution study of these processes can be performed in the field using timely monitored instruments, or conceptually-based hydrologic models. However, this approach requires advancing stormwater modeling techniques using high performance computing. The goal of this work is to develop a novel approach to evaluate BMP implementation using an ultra-high-resolution domain and ParFlow, a physically-based hydrologic model that simulates surface and subsurface water interactions. This study domain is located in Aurora, CO, an area that experienced over 200% urban growth over the last 30 years. The ultra-high-resolution domain was constructed using LIDAR imagery and consisted of 1m x 1m horizontal resolution over a ~7.7 km by 2.1 km lateral extent up to 2 m in the subsurface, with a domain totaling more than 3x106unknowns. Three storm events (wet, dry and normal) were simulated with two pavement types, permeable (K=0.18 mhr-1,Φ=0.1) and impermeable (K=0.0018 mhr-1, Φ=0.06), amounting to 6 simulation scenarios. We investigated changes to stormwater routing and infiltration with and without BMP implementation. Contaminant transport was performed using SLIM-FAST, a Lagrangian, particle tracking approach that allows for complex, contaminant-loading scenarios common in the urban environment. Preliminary results show delayed particle movement within impermeable pavement scenarios and particle trapping along the gutters and rooftop locations. This approach is useful for evaluating the effectiveness of BMPs in trapping and reducing concentrations of emerging contaminants of concern within urban environments.

  3. Nanometer resolution imaging and tracking of fluorescent molecules with minimal photon fluxes

    CERN Document Server

    Balzarotti, Francisco; Gwosch, Klaus C; Gynnå, Arvid H; Westphal, Volker; Stefani, Fernando D; Elf, Johan; Hell, Stefan W

    2016-01-01

    We introduce MINFLUX, a concept for localizing photon emitters in space. By probing the emitter with a local intensity minimum of excitation light, MINFLUX minimizes the fluorescence photons needed for high localization precision. A 22-fold reduction of photon detections over that required in popular centroid-localization is demonstrated. In superresolution microscopy, MINFLUX attained ~1 nm precision, resolving molecules only 6 nm apart. Tracking single fluorescent proteins by MINFLUX increased the temporal resolution and the localizations per trace by 100-fold, as demonstrated with diffusing 30S ribosomal subunits in living E. coli. Since conceptual limits have not been reached, we expect this localization modality to break new ground for observing the dynamics, distribution, and structure of macromolecules in living cells and beyond.

  4. A Microscopic Optically Tracking Navigation System That Uses High-resolution 3D Computer Graphics.

    Science.gov (United States)

    Yoshino, Masanori; Saito, Toki; Kin, Taichi; Nakagawa, Daichi; Nakatomi, Hirofumi; Oyama, Hiroshi; Saito, Nobuhito

    2015-01-01

    Three-dimensional (3D) computer graphics (CG) are useful for preoperative planning of neurosurgical operations. However, application of 3D CG to intraoperative navigation is not widespread because existing commercial operative navigation systems do not show 3D CG in sufficient detail. We have developed a microscopic optically tracking navigation system that uses high-resolution 3D CG. This article presents the technical details of our microscopic optically tracking navigation system. Our navigation system consists of three components: the operative microscope, registration, and the image display system. An optical tracker was attached to the microscope to monitor the position and attitude of the microscope in real time; point-pair registration was used to register the operation room coordinate system, and the image coordinate system; and the image display system showed the 3D CG image in the field-of-view of the microscope. Ten neurosurgeons (seven males, two females; mean age 32.9 years) participated in an experiment to assess the accuracy of this system using a phantom model. Accuracy of our system was compared with the commercial system. The 3D CG provided by the navigation system coincided well with the operative scene under the microscope. Target registration error for our system was 2.9 ± 1.9 mm. Our navigation system provides a clear image of the operation position and the surrounding structures. Systems like this may reduce intraoperative complications.

  5. Studying plus-end tracking at single molecule resolution using TIRF microscopy.

    Science.gov (United States)

    Dixit, Ram; Ross, Jennifer L

    2010-01-01

    The highly dynamic microtubule plus-ends are key sites of regulation that impact the organization and function of the microtubule cytoskeleton. Much of this regulation is performed by the microtubule plus-end tracking (+TIP) family of proteins. +TIPs are a structurally diverse group of proteins that bind to and track with growing microtubule plus-ends in cells. +TIPs regulate microtubule dynamics as well as mediate interactions between microtubule tips and other cellular structures. Most +TIPs can directly bind to microtubules in vitro; however, the mechanisms for their plus-end specificity are not fully understood. Cellular studies of +TIP activity are complicated by the fact that members of the +TIP family of proteins interact with each other to form higher-order protein assemblies. Development of an in vitro system, using minimal components, to study +TIP activity is therefore critical to unequivocally understand the behavior of individual +TIP proteins. Coupled with single molecule imaging, this system provides a powerful tool to study the molecular properties that are important for +TIP function. In this chapter, we describe a detailed protocol for in vitro reconstitution of +TIP activity at single molecule resolution using total internal reflection fluorescence microscopy. Copyright 2010 Elsevier Inc. All rights reserved.

  6. Speckle-modulating optical coherence tomography in living mice and humans

    Science.gov (United States)

    Liba, Orly; Lew, Matthew D.; Sorelle, Elliott D.; Dutta, Rebecca; Sen, Debasish; Moshfeghi, Darius M.; Chu, Steven; de La Zerda, Adam

    2017-06-01

    Optical coherence tomography (OCT) is a powerful biomedical imaging technology that relies on the coherent detection of backscattered light to image tissue morphology in vivo. As a consequence, OCT is susceptible to coherent noise (speckle noise), which imposes significant limitations on its diagnostic capabilities. Here we show speckle-modulating OCT (SM-OCT), a method based purely on light manipulation that virtually eliminates speckle noise originating from a sample. SM-OCT accomplishes this by creating and averaging an unlimited number of scans with uncorrelated speckle patterns without compromising spatial resolution. Using SM-OCT, we reveal small structures in the tissues of living animals, such as the inner stromal structure of a live mouse cornea, the fine structures inside the mouse pinna, and sweat ducts and Meissner's corpuscle in the human fingertip skin--features that are otherwise obscured by speckle noise when using conventional OCT or OCT with current state of the art speckle reduction methods.

  7. Conflict Resolution in Aceh in Light of Track One and a Half Diplomacy

    Directory of Open Access Journals (Sweden)

    Robert M. Heiling

    2008-01-01

    Full Text Available This paper analyzes the role of mediators in the resolution of the Aceh conflict within the framework of a three-step process. Two separate mediation efforts, one conducted by the Centre for Humanitarian Dialogue from 1999 until 2003 and a second one led by Martti Ahtisaari and his Crisis Management Initiative in 2004/2005, attempted to solve the Aceh confl ict. The author shows that beside contextual factors such as ripeness of the conflict and advantageous relations between and characteristics of the conflict parties, the success of Ahtisaari’s engagement can be further explained by procedural factors. These include mediator behaviour and mediation strategies. Furthermore the mediator’s ability to use contacts with official track one actors was crucial in securing the signing as well as the implementation of the present peace agreement. ----- Der Artikel analysiert die Rolle von Mediatoren in der Lösung des Aceh Konfl ikts mittels eines drei-Phasen Modells von Konfliktlösung. Zwei voneinander unabhängige Mediationsverfahren, jenes des Centre for Humanitarian Dialogue von 1999 bis 2003, und ein weiteres geleitet durch Martti Ahtisaari und seiner Crisis Management Initiative in 2004/2005, zielten darauf ab den Konflikt zu lösen. Der Autor zeigt, dass neben kontextuellen Faktoren wie einer “ripeness” des Konflikts sowie günstigen Veränderungen auf Seite der Konfliktparteien, prozedurale Faktoren für den Erfolg Ahtisaaris entscheidend waren. Diese Faktoren beziehen sich auf das Agieren und die Strategien des Mediators. Die Fähigkeit des Mediators, Kontakte zu offiziellen “track one” Akteuren aktiv während des Mediationsprozesses zu nutzen, bildete einen Schlüsselfaktor darin einen Friedensschluss und im weiteren Verlauf eine weitgehend erfolgreiche Umsetzung des aktuellen Abkommens zwischen den ehemaligen Konfliktparteien zu erreichen.

  8. Alterations of left ventricular deformation and cardiac sympathetic derangement in patients with systolic heart failure: a 3D speckle tracking echocardiography and cardiac {sup 123}I-MIBG study

    Energy Technology Data Exchange (ETDEWEB)

    Leosco, Dario; Parisi, Valentina; Pagano, Gennaro; Femminella, Grazia Daniela; Bevilacqua, Agnese; Formisano, Roberto; Ferro, Gaetana; De Lucia, Claudio; Ferrara, Nicola [University Federico II, Department of Translational Medical Science, Naples (Italy); Pellegrino, Teresa [Italian National Research Council (CNR), Institute of Biostructure and Bioimaging, Naples (Italy); University Federico II, Department of Advanced Biomedical Science, Naples (Italy); Paolillo, Stefania [University Federico II, Department of Advanced Biomedical Science, Naples (Italy); SDN Foundation, Institute of Diagnostic and Nuclear Development, Naples (Italy); Prastaro, Maria; Filardi, Pasquale Perrone; Cuocolo, Alberto [University Federico II, Department of Advanced Biomedical Science, Naples (Italy); Rengo, Giuseppe [University Federico II, Department of Translational Medical Science, Naples (Italy); Salvatore Maugeri Foundation, IRCCS, Istituto di Telese, Benevento, BN (Italy)

    2015-09-15

    Myocardial contractile function is under the control of cardiac sympathetic activity. Three-dimensional speckle tracking echocardiography (3D-STE) and cardiac imaging with {sup 123}I-metaiodobenzylguanidine ({sup 123}I-MIBG) are two sophisticated techniques for the assessment of left ventricular (LV) deformation and sympathetic innervation, respectively, which offer important prognostic information in patients with heart failure (HF). The purpose of this investigation was to explore, in patients with systolic HF, the relationship between LV deformation assessed by 3D-STE and cardiac sympathetic derangement evaluated by {sup 123}I-MIBG imaging. We prospectively studied 75 patients with systolic HF. All patients underwent a 3D-STE study (longitudinal, circumferential, area and radial) and {sup 123}I-MIBG planar and SPECT cardiac imaging. 3D-STE longitudinal, circumferential and area strain values were correlated with {sup 123}I-MIBG late heart to mediastinum (H/M) ratio and late SPECT total defect score. After stratification of the patients according to ischaemic or nonischaemic HF aetiology, we observed a good correlation of all 3D-STE measurements with late H/M ratio and SPECT data in the ischaemic group, but in patients with HF of nonischaemic aetiology, no correlation was found between LV deformation and cardiac sympathetic activity. At the regional level, the strongest correlation between LV deformation and adrenergic innervation was found for the left anterior descending coronary artery distribution territory for all four 3D-STE values. In multivariate linear regression analyses, including age, gender, LV ejection fraction, NYHA class, body mass index, heart rate and HF aetiology, only 3D-STE area and radial strain values significantly predicted cardiac sympathetic derangement on {sup 123}I-MIBG late SPECT. This study indicated that 3D-STE measurements are correlated with {sup 123}I-MIBG planar and SPECT data. Furthermore, 3D-STE area and radial strain values

  9. Evolution of subclinical myocardial dysfunction detected by two-dimensional and three-dimensional speckle tracking in asymptomatic type 1 diabetic patients: a long‑term follow-up study.

    Science.gov (United States)

    Ringle, Anne; Dornhorst, Anne; Rehman, Michaela B; Ruisanchez, Cristina; Nihoyannopoulos, Petros

    2017-12-01

    We sought to assess the long-term evolution of left ventricular (LV) function using two-dimensional (2D) and three-dimensional (3D) speckle tracking echocardiography (STE) for the detection of preclinical diabetic cardiomyopathy, in asymptomatic type 1 diabetic patients, over a 6-year follow-up. Sixty-six asymptomatic type 1 diabetic patients with no cardiovascular risk factors were compared to 26 matched healthy controls. Conventional, 2D and 3D-STE were performed at baseline. A subgroup of 14 patients underwent a 6-year follow-up evaluation. At baseline, diabetic patients had similar LV ejection fraction (60 vs 61%; P  = NS), but impaired longitudinal function, as assessed by 2D-global longitudinal strain (GLS) (-18.9 ± 2 vs -20.5 ± 2; P  = 0.0002) and 3D-GLS (-17.5 ± 2 vs -19 ± 2; P  = 0.003). At follow-up, diabetic patients had worsened longitudinal function compared to baseline (2D-GLS: -18.4 ± 1 vs -19.2 ± 1; P  = 0.03). Global circumferential (GCS) and radial (GRS) strains were unchanged at baseline and during follow-up. Metabolic status did not correlate with GLS, whereas GCS and GRS showed a good correlation, suggestive of a compensatory increase of circumferential and radial functions in advanced stages of the disease - long-term diabetes (GCS: -26 ± 3 vs -23.3 ± 3; P  = 0.008) and in the presence of microvascular complications (GRS: 38.8 ± 9 vs 34.3 ± 8; P  = 0.04). Subclinical myocardial dysfunction can be detected by 2D and 3D-STE in type 1 diabetic patients, independently of any other cardiovascular risk factors. Diabetic cardiomyopathy progression was suggested by a mild decrease in longitudinal function at the follow-up, but did not extend to a clinical expression of the disease, as no death or over heart failure was reported. © 2017 The authors.

  10. Speckle suppression in off-axis lensless Fourier transform digital holography

    Science.gov (United States)

    Panezai, Spozmai; Zhao, Jie; Wang, Yunxin; Wang, Dayong; Rong, Lu

    2017-08-01

    Speckle noise suppression in off-axis lensless Fourier transform digital holography by laterally shifting of object is analyzed quantitatively. Speckle decorrelation is directly proportional to the object displacement therefore object is shifted by three different amounts to test its effect on the speckle contrast reduction that is pixel size of camera, averaged speckle size and resolution pixel size of reconstruction plane. Phase-only spatial light modulator (LCOS) is used in object beam path to introduce the lateral shift in its position digitally without mechanical efforts by displaying a grating function. In comparison with the typical methods, the externally input lateral position shifts of object are controlled accurately, which makes the system effective and practicable. Averaged reconstructed results for three quantitative object lateral position shifts are compared and it has been found that the object shift by resolution pixel size of reconstruction plane shows better speckle contrast reduction and is in good agreement with the theoretical prediction.

  11. A Novel Azimuth Super-Resolution Method by Synthesizing Azimuth Bandwidth of Multiple Tracks of Airborne Stripmap SAR Data

    Directory of Open Access Journals (Sweden)

    Yan Wang

    2016-06-01

    Full Text Available Azimuth resolution of airborne stripmap synthetic aperture radar (SAR is restricted by the azimuth antenna size. Conventionally, a higher azimuth resolution should be achieved by employing alternate modes that steer the beam in azimuth to enlarge the synthetic antenna aperture. However, if a data set of a certain region, consisting of multiple tracks of airborne stripmap SAR data, is available, the azimuth resolution of specific small region of interest (ROI can be conveniently improved by a novel azimuth super-resolution method as introduced by this paper. The proposed azimuth super-resolution method synthesize the azimuth bandwidth of the data selected from multiple discontinuous tracks and contributes to a magnifier-like function with which the ROI can be further zoomed in with a higher azimuth resolution than that of the original stripmap images. Detailed derivation of the azimuth super-resolution method, including the steps of two-dimensional dechirping, residual video phase (RVP removal, data stitching and data correction, is provided. The restrictions of the proposed method are also discussed. Lastly, the presented approach is evaluated via both the single- and multi-target computer simulations.

  12. Lineage Tracking for Probing Heritable Phenotypes at Single-Cell Resolution

    Science.gov (United States)

    Cottinet, Denis; Condamine, Florence; Bremond, Nicolas; Griffiths, Andrew D.; Rainey, Paul B.; de Visser, J. Arjan G. M.; Baudry, Jean; Bibette, Jérôme

    2016-01-01

    Determining the phenotype and genotype of single cells is central to understand microbial evolution. DNA sequencing technologies allow the detection of mutants at high resolution, but similar approaches for phenotypic analyses are still lacking. We show that a drop-based millifluidic system enables the detection of heritable phenotypic changes in evolving bacterial populations. At time intervals, cells were sampled and individually compartmentalized in 100 nL drops. Growth through 15 generations was monitored using a fluorescent protein reporter. Amplification of heritable changes–via growth–over multiple generations yields phenotypically distinct clusters reflecting variation relevant for evolution. To demonstrate the utility of this approach, we follow the evolution of Escherichia coli populations during 30 days of starvation. Phenotypic diversity was observed to rapidly increase upon starvation with the emergence of heritable phenotypes. Mutations corresponding to each phenotypic class were identified by DNA sequencing. This scalable lineage-tracking technology opens the door to large-scale phenotyping methods with special utility for microbiology and microbial population biology. PMID:27077662

  13. Reproducibilidad del strain longitudinal global del ventrículo izquierdo por ecocardiografía bidimensional speckle tracking: Estudio Longitudinal de Salud del Adulto (ELSA-Brasil

    Directory of Open Access Journals (Sweden)

    Wilson Cañon-Montañez

    2017-11-01

    Full Text Available Resumen: Introducción: Se han propuesto técnicas ecocardiográficas avanzadas como el strain longitudinal global por ecocardiografía bidimensional speckle tracking para la detección de alteraciones precoces de la función sistólica del ventrículo izquierdo. La evaluación de la reproducibilidad del strain longitudinal global es fundamental para su aplicación clínica en diferentes escenarios. Objetivo: Estimar la reproducibilidad del strain longitudinal global del ventrículo izquierdo en individuos de un estudio de cohorte del Brasil. Métodos: La reproducibilidad del strain longitudinal global del ventrículo izquierdo fue evaluada mediante lectura y análisis de imágenes de ecocardiografía de una muestra aleatoria de 50 participantes de la línea de base del Estudio Longitudinal de Salud del Adulto (ELSA-Brasil. Resultados: Los participantes tenían una edad promedio de 49,7 ± 7,3 años, 54% eran mujeres y la media del strain longitudinal global fue –19,5% ± 1,9%. La reproducibilidad interobservador de la medida del strain longitudinal global mostró un coeficiente de variación de 7,4% y un coeficiente de correlación intraclase de 0,76 (IC 95%: 0,61, 0,86. El análisis del acuerdo interobservador de las medidas del strain longitudinal global mediante el método de Bland & Altman evidenció un promedio de diferencias de 0,1% ± 1,4% y unos límites de acuerdo superior de 2,9 e inferior de –2,7. Conclusiones: Hubo una reproducibilidad adecuada de las medidas del strain longitudinal global del ventrículo izquierdo en participantes del ELSA-Brasil y los valores fueron similares a los reportados en otros estudios epidemiológicos longitudinales. Los hallazgos refuerzan la utilidad del strain longitudinal global como un índice clínico de deformación miocárdica, capaz de detectar alteraciones subclínicas de la contractilidad mioc

  14. Speckle Imaging at Gemini and the DCT

    Science.gov (United States)

    Horch, E. P.; Löbb, J.; Howell, S. B.; van Altena, W. F.; Henry, T. J.; van Belle, G. T.

    2018-01-01

    A program of speckle observations at Lowell Observatory's Discovery Channel Telescope (DCT) and the Gemini North and South Telescopes will be described. It has featured the Differential Speckle Survey Instrument (DSSI), built at Southern Connecticut State University in 2008. DSSI is a dual-port system that records speckle images in two colors simultaneously and produces diffraction limited images to V˜ 16.5 mag at Gemini and V˜ 14.5 mag at the DCT. Of the several science projects that are being pursued at these telescopes, three will be highlighted here. The first is high-resolution follow-up observations for Kepler and K2 exoplanet missions, the second is a study of metal-poor spectroscopic binaries in an attempt to resolve these systems and determine their visual orbits en route to making mass determinations, and the third is a systematic survey of nearby late-type dwarfs, where the multiplicity fraction will be directly measured and compared to that of G dwarfs. The current status of these projects is discussed and some representative results are given.

  15. Ba II 4554 Å speckle imaging as solar Doppler diagnostic

    NARCIS (Netherlands)

    Sütterlin, P.; Rutten, R.J.; Skomorovsky, V.I.

    2001-01-01

    We present observations testing the Dopplergram capability of a narrow-band (80 mÅ) Lyot filter imaging the solar surface in the wings of the Ba II 4554 Å resonance line in combination with speckle reconstruction to obtain high angular resolution. The Ba II line is found to be an excellent tool

  16. Visual based laser speckle pattern recognition method for structural health monitoring

    Science.gov (United States)

    Park, Kyeongtaek; Torbol, Marco

    2017-04-01

    This study performed the system identification of a target structure by analyzing the laser speckle pattern taken by a camera. The laser speckle pattern is generated by the diffuse reflection of the laser beam on a rough surface of the target structure. The camera, equipped with a red filter, records the scattered speckle particles of the laser light in real time and the raw speckle image of the pixel data is fed to the graphic processing unit (GPU) in the system. The algorithm for laser speckle contrast analysis (LASCA) computes: the laser speckle contrast images and the laser speckle flow images. The k-mean clustering algorithm is used to classify the pixels in each frame and the clusters' centroids, which function as virtual sensors, track the displacement between different frames in time domain. The fast Fourier transform (FFT) and the frequency domain decomposition (FDD) compute the modal properties of the structure: natural frequencies and damping ratios. This study takes advantage of the large scale computational capability of GPU. The algorithm is written in Compute Unifies Device Architecture (CUDA C) that allows the processing of speckle images in real time.

  17. Speckle pattern processing by digital image correlation

    Directory of Open Access Journals (Sweden)

    Gubarev Fedor

    2016-01-01

    Full Text Available Testing the method of speckle pattern processing based on the digital image correlation is carried out in the current work. Three the most widely used formulas of the correlation coefficient are tested. To determine the accuracy of the speckle pattern processing, test speckle patterns with known displacement are used. The optimal size of a speckle pattern template used for determination of correlation and corresponding the speckle pattern displacement is also considered in the work.

  18. Evaluation of myocardial strain and artery elasticity using speckle tracking echocardiography and high-resolution ultrasound in patients with bicuspid aortic valve.

    Science.gov (United States)

    Li, Yang; Deng, You-Bin; Bi, Xiao-Jun; Liu, Ya-Ni; Zhang, Jun; Li, Li

    2016-07-01

    Reduced artery elasticity and reduced myocardial strain were present in patients with bicuspid aortic valve (BAV). Their relation to dilation of proximal aorta is unclear. We aimed to study their relation to dilation of proximal aorta. We studied 57 BAV patients categorized into 2 subgroup according to proximal ascending aortic dimensions (nondilated elasticity and myocardial strain in BAV patients, supporting the need for detailed and extensive vascular and cardiac surveillance in BAV patients.

  19. Ultra-scale vehicle tracking in low spatial-resolution and low frame-rate overhead video

    Energy Technology Data Exchange (ETDEWEB)

    Carrano, C J

    2009-05-20

    Overhead persistent surveillance systems are becoming more capable at acquiring wide-field image sequences for long time-spans. The need to exploit this data is becoming ever greater. The ability to track a single vehicle of interest or to track all the observable vehicles, which may number in the thousands, over large, cluttered regions while they persist in the imagery either in real-time or quickly on-demand is very desirable. With this ability we can begin to answer a number of interesting questions such as, what are normal traffic patterns in a particular region or where did that truck come from? There are many challenges associated with processing this type of data, some of which we will address in the paper. Wide-field image sequences are very large with many thousands of pixels on a side and are characterized by lower resolutions (e.g. worse than 0.5 meters/pixel) and lower frame rates (e.g. a few Hz or less). The objects in the scenery can vary in size, density, and contrast with respect to the background. At the same time the background scenery provides a number of clutter sources both man-made and natural. We describe our current implementation of an ultrascale capable multiple-vehicle tracking algorithm for overhead persistent surveillance imagery as well as discuss the tracking and timing performance of the currently implemented algorithm which is aimed at utilizing grayscale electrooptical image sequences alone for the track segment generation.

  20. Simultaneous laser speckle imaging and positron emission tomography

    Science.gov (United States)

    Gramer, M.; Feuerstein, D.; Backes, H.; Takagaki, M.; Kumagai, T.; Graf, R.

    2013-06-01

    Complex biological systems often require measurements of multiple parameters with high temporal and spatial resolution. Multimodal approaches and the combination of methods are therefore a powerful tool to address such scientific questions. Laser speckle imaging (LSI) is an optical method that monitors dynamic changes in cortical blood flow (CBF) with high temporal resolution. Positron emission tomography (PET) allows for quantitative imaging of physiological processes and is a gold standard method to determine absolute cerebral blood flow. We developed a setup that allows simultaneous measurement with both modalities. Here, we simultaneously measured CBF with PET and LSI in rats and analyzed how the correlation of PET and LSI is modified when (1) different methods are used for the calculation of speckle inverse correlation time (ICT), (2) speckle data is acquired through thinned or craniectomized skull, (3) influence of surface vessels is removed from the speckle data. For the latter, a method for automated vessel segmentation from LSI data was developed. We obtained the best correlation (R² = 0.890, pICT. Thus, LSI provides CBF in absolute units at high temporal resolution.

  1. Color speckle in laser displays

    Science.gov (United States)

    Kuroda, Kazuo

    2015-07-01

    At the beginning of this century, lighting technology has been shifted from discharge lamps, fluorescent lamps and electric bulbs to solid-state lighting. Current solid-state lighting is based on the light emitting diodes (LED) technology, but the laser lighting technology is developing rapidly, such as, laser cinema projectors, laser TVs, laser head-up displays, laser head mounted displays, and laser headlamps for motor vehicles. One of the main issues of laser displays is the reduction of speckle noise1). For the monochromatic laser light, speckle is random interference pattern on the image plane (retina for human observer). For laser displays, RGB (red-green-blue) lasers form speckle patterns independently, which results in random distribution of chromaticity, called color speckle2).

  2. SU-E-J-197: Investigation of Microsoft Kinect 2.0 Depth Resolution for Patient Motion Tracking

    Energy Technology Data Exchange (ETDEWEB)

    Silverstein, E; Snyder, M [Wayne State University, Detroit, MI (United States)

    2015-06-15

    Purpose: Investigate the use of the Kinect 2.0 for patient motion tracking during radiotherapy by studying spatial and depth resolution capabilities. Methods: Using code written in C#, depth map data was abstracted from the Kinect to create an initial depth map template indicative of the initial position of an object to be compared to the depth map of the object over time. To test this process, simple setup was created in which two objects were imaged: a 40 cm × 40 cm board covered in non reflective material and a 15 cm × 26 cm textbook with a slightly reflective, glossy cover. Each object, imaged and measured separately, was placed on a movable platform with object to camera distance measured. The object was then moved a specified amount to ascertain whether the Kinect’s depth camera would visualize the difference in position of the object. Results: Initial investigations have shown the Kinect depth resolution is dependent on the object to camera distance. Measurements indicate that movements as small as 1 mm can be visualized for objects as close as 50 cm away. This depth resolution decreases linearly with object to camera distance. At 4 m, the depth resolution had decreased to observe a minimum movement of 1 cm. Conclusion: The improved resolution and advanced hardware of the Kinect 2.0 allows for increase of depth resolution over the Kinect 1.0. Although obvious that the depth resolution should decrease with increasing distance from an object given the decrease in number of pixels representing said object, the depth resolution at large distances indicates its usefulness in a clinical setting.

  3. Assessing the capability of high resolution climatic model experiments to simulate Mediterranean cyclonic tracks

    Science.gov (United States)

    Hatzaki, M.; Flocas, H. A.; Giannakopoulos, C.; Kostopoulou, E.; Kouroutzoglou, I.; Keay, K.; Simmonds, I.

    2010-09-01

    In this study, a comparison of a reanalysis driven simulation to a GCM driven simulation of a regional climate model is performed in order to assess the model's ability to capture the climatic characteristics of cyclonic tracks in the Mediterranean in the present climate. The ultimate scope of the study will be to perform a future climate projection related to cyclonic tracks in order to better understand and assess climate change in the Mediterranean. The climatology of the cyclonic tracks includes inter-monthly variations, classification of tracks according to their origin domain, dynamic and kinematic characteristics, as well as trend analysis. For this purpose, the ENEA model is employed based on PROTHEUS system composed of the RegCM atmospheric regional model and the MITgcm ocean model, coupled through the OASIS3 flux coupler. These model data became available through the EU Project CIRCE which aims to perform, for the first time, climate change projections with a realistic representation of the Mediterranean Sea. Two experiments are employed; a) the ERA402 with lateral Boundary conditions from ERA40 for the 43-year period 1958-2000, and b) the EH5OM_20C3M where the lateral boundary conditions for the atmosphere (1951-2000) are taken from the ECHAM5-MPIOM 20c3m global simulation (run3) included in the IPCC-AR4. The identification and tracking of cyclones is performed with the aid of the Melbourne University algorithm (MS algorithm), according to the Lagrangian perspective. MS algorithm characterizes a cyclone only if a vorticity maximum could be connected with a local pressure minimum. This approach is considered to be crucial, since open lows are also incorporated into the storm life-cycle, preventing possible inappropriate time series breaks, if a temporary weakening to an open-low state occurs. The model experiments verify that considerable inter-monthly variations of track density occur in the Mediterranean region, consistent with previous studies. The

  4. Evaluation of low viscosity variations in fluids using temporal and spatial analysis of the speckle pattern.

    Science.gov (United States)

    Nader, Christelle Abou; Pellen, Fabrice; Roquefort, Philippe; Aubry, Thierry; Le Jeune, Bernard; Le Brun, Guy; Abboud, Marie

    2016-06-01

    The noninvasive detection of a material's viscoelasticity is of great importance in the medical field. In fact, certain diseases cause changes in tissue structure and biological fluid viscosity; tracking those changes allows for detection of these diseases. Rheological measurements are also imperative in the industrial field, where it is necessary to characterize a material's viscoelasticity for manufacturing purposes. In this Letter, we present a noncontact, noninvasive, and low cost method for determining low viscosity values and variations in fluids. Laser speckle and viscometric measurements are performed on test samples having low scattering coefficients and low viscosities. The speckle spatial analysis proved to be as accurate as the speckle temporal correlation method reported in previous studies. Very low viscosities of the order of 1 mPa.s were retrieved for the first time using speckle images with either a frame rate of 1950 fps or a single acquired image.

  5. Tracking inside the ALICE Inner Tracking System

    CERN Document Server

    Badalà, A; Lo Re, G; Palmeri, A; Pappalardo, G S; Pulvirenti, A; Riggi, F

    2002-01-01

    One of the main purposes of the ALICE Inner Tracking System (ITS) is to improve the resolution of the track parameters found in the main ALICE tracker detector, the Time Projector Chamber (TPC). Some results about tracking efficiency and resolution of track parameters obtained with a tracking code, based on the Kalman filter algorithm are presented.

  6. The Magnetic Nanoparticle Movement in Magnetic Fluid Characterized by the Laser Dynamic Speckle Interferometry

    Directory of Open Access Journals (Sweden)

    Xijun Wang

    2014-01-01

    Full Text Available A dual scanning laser speckle interferometry experiment was designed to observe the dynamic behavior of the magnetic fluid actuated by a magnetic field. In order to improve the spatial resolution of the dynamic speckle measurement, the phase delay scanning was used to compensate the additional phase variation which was caused by the transverse scanning. The correlation coefficients corresponding to the temporal dynamic speckle patterns within the same time interval scattering from the nanoparticles were calculated in the experiment on nanoscale magnetic clusters. In the experiment, the speckle of the magnetic nanoparticle fluid movement has been recorded by the lens unmounted CCD within the interferometry strips, although the speckle led to the distinguished annihilation of the light coherence. The results have showed that the nanoparticle fluid dynamic properties appeared synergistically in the fringe speckles. The analyses of the nanoparticle's relative speed and the speckle pattern moving amount in the fringes have proved the nanoparticle’s movement in a laminar flow in the experiment.

  7. Fluorescent Nanodiamond: A Versatile Tool for Long-Term Cell Tracking, Super-Resolution Imaging, and Nanoscale Temperature Sensing.

    Science.gov (United States)

    Hsiao, Wesley Wei-Wen; Hui, Yuen Yung; Tsai, Pei-Chang; Chang, Huan-Cheng

    2016-03-15

    Fluorescent nanodiamond (FND) has recently played a central role in fueling new discoveries in interdisciplinary fields spanning biology, chemistry, physics, and materials sciences. The nanoparticle is unique in that it contains a high density ensemble of negatively charged nitrogen-vacancy (NV(-)) centers as built-in fluorophores. The center possesses a number of outstanding optical and magnetic properties. First, NV(-) has an absorption maximum at ∼550 nm, and when exposed to green-orange light, it emits bright fluorescence at ∼700 nm with a lifetime of longer than 10 ns. These spectroscopic properties are little affected by surface modification but are distinctly different from those of cell autofluorescence and thus enable background-free imaging of FNDs in tissue sections. Such characteristics together with its excellent biocompatibility render FND ideal for long-term cell tracking applications, particularly in stem cell research. Next, as an artificial atom in the solid state, the NV(-) center is perfectly photostable, without photobleaching and blinking. Therefore, the NV-containing FND is suitable as a contrast agent for super-resolution imaging by stimulated emission depletion (STED). An improvement of the spatial resolution by 20-fold is readily achievable by using a high-power STED laser to deplete the NV(-) fluorescence. Such improvement is crucial in revealing the detailed structures of biological complexes and assemblies, including cellular organelles and subcellular compartments. Further enhancement of the resolution for live cell imaging is possible by manipulating the charge states of the NV centers. As the "brightest" member of the nanocarbon family, FND holds great promise and potential for bioimaging with unprecedented resolution and precision. Lastly, the NV(-) center in diamond is an atom-like quantum system with a total electron spin of 1. The ground states of the spins show a crystal field splitting of 2.87 GHz, separating the ms = 0 and

  8. The POKEMON Speckle Survey of Nearby M-Dwarfs

    Science.gov (United States)

    van Belle, Gerard; von Braun, Kaspar; Horch, Elliott; Clark, Catherine; DSSI Speckle Team

    2018-01-01

    The POKEMON (Pervasive Overview of Kompanions of Every M-dwarf in Our Neighborhood) survey of nearby M-dwarfs intends to inspect, at diffraction-limited resolution, every low-mass star out to 15pc, along with selected additional objects to 25pc. The primary emphasis of the survey is detection of low-mass companions to these M-dwarfs for refinement of the low-mass star multiplicity rate. The resultant catalog of M-dwarf companions will also guide immediate refinement of transit planet detection results from surveys such as TESS. POKEMON is using Lowell Observatory's 4.3-m Discovery Channel Telescope (DCT) with the Differential Speckle Survey Instrument (DSSI) speckle camera, along with the NN-Explore Exoplanet Stellar Speckle Imager (NESSI) speckle imager on 3.5-m WIYN; the survey takes advantage of the extremely rapid observing cadence rates possible with WIYN and (especially) DCT. The current status and preliminary results from the first 20+ nights of observing will be presented. Gotta observe them all!

  9. Objective speckle velocimetry for autonomous vehicle odometry.

    Science.gov (United States)

    Francis, D; Charrett, T O H; Waugh, L; Tatam, R P

    2012-06-01

    Speckle velocimetry is investigated as a means of determining odometry data with potential for application on autonomous robotic vehicles. The technique described here relies on the integration of translation measurements made by normalized cross-correlation of speckle patterns to determine the change in position over time. The use of objective (non-imaged) speckle offers a number of advantages over subjective (imaged) speckle, such as a reduction in the number of optical components, reduced modulation of speckles at the edges of the image, and improved light efficiency. The influence of the source/detector configuration on the speckle translation to vehicle translation scaling factor for objective speckle is investigated using a computer model and verified experimentally. Experimental measurements are presented at velocities up to 80  mm s(-1) which show accuracy better than 0.4%.

  10. Tracking the Resolution of Student Misconceptions about the Central Dogma of Molecular Biology.

    Science.gov (United States)

    Briggs, Amy G; Morgan, Stephanie K; Sanderson, Seth K; Schulting, Molly C; Wieseman, Laramie J

    2016-12-01

    The goal of our study was to track changes in student understanding of the central dogma of molecular biology before and after taking a genetics course. Concept maps require the ability to synthesize new information into existing knowledge frameworks, and so the hypothesis guiding this study was that student performance on concept maps reveals specific central dogma misconceptions gained, lost, and retained by students. Students in a genetics course completed pre- and posttest concept mapping tasks using terms related to the central dogma. Student maps increased in complexity and validity, indicating learning gains in both content and complexity of understanding. Changes in each of the 351 possible connections in the mapping task were tracked for each student. Our students did not retain much about the central dogma from their introductory biology courses, but they did move to more advanced levels of understanding by the end of the genetics course. The information they retained from their introductory courses focused on structural components (e.g., protein is made of amino acids) and not on overall mechanistic components (e.g., DNA comes before RNA, the ribosome makes protein). Students made the greatest gains in connections related to transcription, and they resolved the most prior misconceptions about translation. These concept-mapping tasks revealed that students are able to correct prior misconceptions about the central dogma during an intermediate-level genetics course. From these results, educators can design new classroom interventions to target those aspects of this foundational principle with which students have the most trouble.

  11. Improved tracking and resolution of bacteria in holographic microscopy using dye and fluorescent protein labeling

    Directory of Open Access Journals (Sweden)

    Jay eNadeau

    2016-04-01

    Full Text Available Digital holographic microscopy (DHM is an emerging imaging technique that permits instantaneous capture of a relatively large sample volume. However, large volumes usually come at the expense of lower spatial resolution, and the technique has rarely been used with prokaryotic cells due to their small size and low contrast. In this paper we demonstrate the use of a Mach-Zehnder dual-beam instrument for imaging of labeled and unlabeled bacteria and microalgae. Spatial resolution of 0.3 micrometers is achieved, providing a sampling of several pixels across a typical prokaryotic cell. Both cellular motility and morphology are readily recorded. The use of dyes provides both amplitude and phase contrast improvement and is of use to identify cells in dense samples.

  12. High resolution wireless body area network with statistically synchronized sensor data for tracking pulse wave velocity.

    Science.gov (United States)

    Li, Kejia; Warren, Steve

    2012-01-01

    Wireless body area networks (WBANs) will take on more diverse forms in terms of their sensor combinations and communication protocols as their presence is extended to a greater number of monitoring scenarios. This paper presents an application layer protocol that solves issues caused by sensor nodes that must compete for high speed, real-time communication with the receiver. Such applications emphasize the delivery of large amounts of raw data from different sensor nodes in a time-synchronized manner, rather than channels that experience intermittent operation. An example of tracking pulse wave velocity (PWV) is introduced in this paper, where high-precision PWVs are estimated with the help of timeline recovery and feature extraction processes in MATLAB.

  13. Tracking the Resolution of Student Misconceptions about the Central Dogma of Molecular Biology†

    Science.gov (United States)

    Briggs, Amy G.; Morgan, Stephanie K.; Sanderson, Seth K.; Schulting, Molly C.; Wieseman, Laramie J.

    2016-01-01

    The goal of our study was to track changes in student understanding of the central dogma of molecular biology before and after taking a genetics course. Concept maps require the ability to synthesize new information into existing knowledge frameworks, and so the hypothesis guiding this study was that student performance on concept maps reveals specific central dogma misconceptions gained, lost, and retained by students. Students in a genetics course completed pre- and posttest concept mapping tasks using terms related to the central dogma. Student maps increased in complexity and validity, indicating learning gains in both content and complexity of understanding. Changes in each of the 351 possible connections in the mapping task were tracked for each student. Our students did not retain much about the central dogma from their introductory biology courses, but they did move to more advanced levels of understanding by the end of the genetics course. The information they retained from their introductory courses focused on structural components (e.g., protein is made of amino acids) and not on overall mechanistic components (e.g., DNA comes before RNA, the ribosome makes protein). Students made the greatest gains in connections related to transcription, and they resolved the most prior misconceptions about translation. These concept-mapping tasks revealed that students are able to correct prior misconceptions about the central dogma during an intermediate-level genetics course. From these results, educators can design new classroom interventions to target those aspects of this foundational principle with which students have the most trouble. PMID:28101260

  14. Tracking the Resolution of Student Misconceptions about the Central Dogma of Molecular Biology

    Directory of Open Access Journals (Sweden)

    Amy G. Briggs

    2016-12-01

    Full Text Available The goal of our study was to track changes in student understanding of the central dogma of molecular biology before and after taking a genetics course. Concept maps require the ability to synthesize new information into existing knowledge frameworks, and so the hypothesis guiding this study was that student performance on concept maps reveals specific central dogma misconceptions gained, lost, and retained by students. Students in a genetics course completed pre- and posttest concept mapping tasks using terms related to the central dogma. Student maps increased in complexity and validity, indicating learning gains in both content and complexity of understanding. Changes in each of the 351 possible connections in the mapping task were tracked for each student. Our students did not retain much about the central dogma from their introductory biology courses, but they did move to more advanced levels of understanding by the end of the genetics course. The information they retained from their introductory courses focused on structural components (e.g., protein is made of amino acids and not on overall mechanistic components (e.g., DNA comes before RNA, the ribosome makes protein. Students made the greatest gains in connections related to transcription, and they resolved the most prior misconceptions about translation. These concept-mapping tasks revealed that students are able to correct prior misconceptions about the central dogma during an intermediate-level genetics course. From these results, educators can design new classroom interventions to target those aspects of this foundational principle with which students have the most trouble.

  15. Monitoring Fast-Moving Landslide in the Three Gorges Area By Offset Tracking Method with High-Resolution SAR Data

    Science.gov (United States)

    Liao, M.; Shi, X.; Zhang, L.; Balz, T.

    2014-12-01

    Landslide has long been considered as a major geological hazard with great threats to local residents and social economic developments within the Three Gorges area, China. With the regular operation of Three Gorges Dam since 2009, the reservoir water level undergoes an annual cycle from 145 m in early summer to 175 m in early winter caused by storage and discharge operations. Consequently, many ancient landslides were activated by such large variations of water level. One of typical examples is the famous Shuping landslide located in Zigui County. To reduce the risks of landslide collapse, long-term monitoring of ground surface deformation must be carried out. Terrestrial surveillance like GPS and extensometer have been installed at Shuping in 2003. Although these methods can achieve highly accurate displacement measurements, only sparse points can be observed, which is far from the requirement of monitoring vast reservoir area coverage. For such a vast and inaccessible area, D-InSAR and PS-InSAR can measure long-term and continuous displacement trends. Nevertheless, it has been revealed by several studies that InSAR can hardly retrieve accurate deformation signal on fast-moving landslides such as Shuping. Therefore, we further investigated the feasibility and effectiveness of pixel offset tracking (POT) method to detect fast-moving with high-resolution SAR data. One of the key points is to estimate displacement at each pixel through subpixel-level SAR image matching. In order to tackle the difficulties of using traditional POT technique, the point-like target offset tracking (PTOT) is developed. By making use of point-like targets with stable backscattering behavior over long time span, PTOT method is can achieve more reliable results with accuracies at 1/20 of SAR pixel resolution. More importantly, PTOT method can measure two-dimensional displacements, i.e. in both azimuth and slant range direction, while InSAR can measure displacement only along the line

  16. Ex-situ tracking solid oxide cell electrode microstructural evolution in a redox cycle by high resolution ptychographic nanotomography

    DEFF Research Database (Denmark)

    De Angelis, Salvatore; Jørgensen, Peter Stanley; Esposito, Vincenzo

    2017-01-01

    , the nickel and pore networks undergo major reorganization and the formation of internal voids is observed in the nickel-oxide particles after the oxidation. These observations are discussed in terms of reaction kinetics, electrode mechanical stress and the consequences of redox cycling on electrode......For solid oxide fuel and electrolysis cells, precise tracking of 3D microstructural change in the electrodes during operation is considered critical to understand the complex relationship between electrode microstructure and performance. Here, for the first time, we report a significant step...... towards this aim by visualizing a complete redox cycle in a solid oxide cell (SOC) electrode. The experiment demonstrates synchrotron-based ptychography as a method of imaging SOC electrodes, providing an unprecedented combination of 3D image quality and spatial resolution among non-destructive imaging...

  17. Investigating spatial and volumetric trends in silicic volcanism along the Yellowstone hotspot track using high-resolution thermomechanical numerical models

    Science.gov (United States)

    Colon, D.; Bindeman, I. N.; Gerya, T.

    2015-12-01

    Roughly 2 Ma gaps exist between the Picabo and Heise (from ~8.4 to 6.6Ma) and the Heise and Yellowstone (4.40 to 2.1 Ma) centers along the Yellowstone hotspot track, each of which experienced magmatic activity for several million years. We employ high-resolution magmatic-thermomechanical models of the interaction between a mantle plume and thick continental crust to investigate the causes of the spatial and temporal jumps that occur between these eruptive centers, using a stress implementation of magmatic processes, nonlinear temperature-dependent melting, and progressive depletion the rocks from which magmas are extracted. We investigate two possible mechanisms of these jumps in active centers. First, the spacing between eruptive centers is a function of the longevity of amagma conduit in beneath each eruptive center, which must be abandoned when the crust moves too far away from the center of the hotspot, with the distance traveled by the plate in this time determining the spacing between eruptive centers. Alternatively, the cessation of activity at a given eruptive center is controlled by the formation of geochemically depleted "dead zones" which force any new silicic volcanism to occur in a new area of less depleted crust, with the spacing between centers controlled by the size of these dead zones. By varying the speed of the crust over the hotspot, the thickness and composition of the crust, we can determine the relative importance of these two processes for volcanism along the Yellowstone hotspot track has likely changed over time, with implications for changes in average eruptive volumes and repose times between large eruptions over the last 12 Ma. Early results suggest that heating of the crust causes areas of melt accumulation to move upward with time before resetting to a deeper level as the crust moves over the hotspot, a possible additional source of discrete behavior along the hotspot track. We check our results using existing geochemical constraints.

  18. Velocity dependence of image speckles produced by a moving diffuser under dynamic speckle illumination

    Science.gov (United States)

    Okamoto, Takashi; Asakura, Toshimitsu

    1990-06-01

    The velocity dependence has been investigated experimentally for the image speckles produced by a moving diffuse object under illumination of a dynamic speckle pattern. The boiling motion of the illuminating speckle pattern has little influence on the resultant speckle intensity fluctuations at the image plane if it is detected through a lens having a large pupil. In this case, the time-correlation length of speckle intensity fluctuations is inversely proportional to the object velocity. For the case where a translating speckle pattern illuminates the diffuser, its motion strongly affects the autocorrelation function of resultant speckle intensity fluctuations. The relationship between the pupil size of the imaging lens and the temporal behavior of image speckles is also considered.

  19. Multivariate EEG analyses support high-resolution tracking of feature-based attentional selection.

    Science.gov (United States)

    Fahrenfort, Johannes Jacobus; Grubert, Anna; Olivers, Christian N L; Eimer, Martin

    2017-05-15

    The primary electrophysiological marker of feature-based selection is the N2pc, a lateralized posterior negativity emerging around 180-200 ms. As it relies on hemispheric differences, its ability to discriminate the locus of focal attention is severely limited. Here we demonstrate that multivariate analyses of raw EEG data provide a much more fine-grained spatial profile of feature-based target selection. When training a pattern classifier to determine target position from EEG, we were able to decode target positions on the vertical midline, which cannot be achieved using standard N2pc methodology. Next, we used a forward encoding model to construct a channel tuning function that describes the continuous relationship between target position and multivariate EEG in an eight-position display. This model can spatially discriminate individual target positions in these displays and is fully invertible, enabling us to construct hypothetical topographic activation maps for target positions that were never used. When tested against the real pattern of neural activity obtained from a different group of subjects, the constructed maps from the forward model turned out statistically indistinguishable, thus providing independent validation of our model. Our findings demonstrate the power of multivariate EEG analysis to track feature-based target selection with high spatial and temporal precision.

  20. Tracking channel bed resiliency in forested mountain catchments using high temporal resolution channel bed movement

    Science.gov (United States)

    Martin, Sarah E.; Conklin, Martha H.

    2018-01-01

    This study uses continuous-recording load cell pressure sensors in four, high-elevation (1500-1800 m), Sierra Nevada headwater streams to collect high-temporal-resolution, bedload-movement data for investigating the channel bed movement patterns within these streams for water years 2012-2014. Data show an annual pattern where channel bed material in the thalweg starts to build up in early fall, peaks around peak snow melt, and scours back to baseline levels during hydrograph drawdown and base flow. This pattern is punctuated by disturbance and recovery of channel bed material associated with short-term storm events. A conceptual model, linking sediment sources at the channel margins to patterns of channel bed fill and scour in the thalweg, is proposed building on the results of Martin et al. (2014). The material in the thalweg represents a balance between sediment supply from the channel margins and sporadic, conveyor-belt-like downstream transport in the thalweg. The conceptual model highlights not only the importance of production and transport rates but also that seasonal connectedness between the margins and thalweg is a key sediment control, determining the accumulation rate of sediment stores at the margins and the redistribution of sediment from margins to thalweg that feeds the conveyor belt. Disturbance and recovery cycles are observed at multiple temporal scales; but long term, the channel beds are stable, suggesting that the beds act as short-term storage for sediment but are in equilibrium interannually. The feasibility of use for these sensors in forested mountain stream environments is tested. Despite a high failure rate (50%), load cell pressure sensors show potential for high-temporal-resolution bedload measurements, allowing for the collection of channel bed movement data to move beyond time-integrated change measurements - where many of the subtleties of bedload movement patterns may be missed - to continuous and/or real-time measurements. This

  1. EEG can track the time course of successful reference resolution in small visual worlds

    Directory of Open Access Journals (Sweden)

    Christian eBrodbeck

    2015-11-01

    Full Text Available Previous research has shown that language comprehenders resolve reference quickly and incrementally, but not much is known about the neural processes and representations that are involved. Studies of visual short-term memory suggest that access to the representation of an item from a previously seen display is associated with a negative evoked potential at posterior electrodes contralateral to the spatial location of that item in the display. In this paper we demonstrate that resolving the reference of a noun phrase in a recently seen visual display is associated with an event-related potential that is analogous to this effect. Our design was adapted from the visual world paradigm: in each trial, participants saw a display containing 3 simple objects, followed by a question about the objects, such as Was the pink fish next to a boat?, presented word by word. Questions differed in whether the color adjective allowed the reader to identify the referent of the noun phrase or not (i.e., whether one or more objects of the named color were present. Consistent with our hypothesis, we observed that reference resolution by the adjective was associated with a negative evoked potential at posterior electrodes contralateral to spatial location of the referent, starting approximately 333 ms after the onset of the adjective. The fact that the laterality of the effect depended upon the location of the referent within the display suggests that reference resolution in visual domains involves, at some level, a modality-specific representation. In addition, the effect gives us an estimate of the time course of processing from perception of the written word to the point at which its meaning is brought into correspondence with the referential domain.

  2. EEG can Track the Time Course of Successful Reference Resolution in Small Visual Worlds.

    Science.gov (United States)

    Brodbeck, Christian; Gwilliams, Laura; Pylkkänen, Liina

    2015-01-01

    Previous research has shown that language comprehenders resolve reference quickly and incrementally, but not much is known about the neural processes and representations that are involved. Studies of visual short-term memory suggest that access to the representation of an item from a previously seen display is associated with a negative evoked potential at posterior electrodes contralateral to the spatial location of that item in the display. In this paper we demonstrate that resolving the reference of a noun phrase in a recently seen visual display is associated with an event-related potential that is analogous to this effect. Our design was adapted from the visual world paradigm: in each trial, participants saw a display containing three simple objects, followed by a question about the objects, such as Was the pink fish next to a boat?, presented word by word. Questions differed in whether the color adjective allowed the reader to identify the referent of the noun phrase or not (i.e., whether one or more objects of the named color were present). Consistent with our hypothesis, we observed that reference resolution by the adjective was associated with a negative evoked potential at posterior electrodes contralateral to spatial location of the referent, starting approximately 333 ms after the onset of the adjective. The fact that the laterality of the effect depended upon the location of the referent within the display suggests that reference resolution in visual domains involves, at some level, a modality-specific representation. In addition, the effect gives us an estimate of the time course of processing from perception of the written word to the point at which its meaning is brought into correspondence with the referential domain.

  3. Statistics of spatially integrated speckle intensity difference

    DEFF Research Database (Denmark)

    Hanson, Steen Grüner; Yura, Harold

    2009-01-01

    We consider the statistics of the spatially integrated speckle intensity difference obtained from two separated finite collecting apertures. For fully developed speckle, closed-form analytic solutions for both the probability density function and the cumulative distribution function are derived...... here for both arbitrary values of the mean number of speckles contained within an aperture and the degree of coherence of the optical field. Additionally, closed-form expressions are obtained for the corresponding nth statistical moments....

  4. High-Resolution Microbiome Profiling for Detection and Tracking of Salmonella enterica

    Directory of Open Access Journals (Sweden)

    Christopher J. Grim

    2017-08-01

    Full Text Available 16S rRNA community profiling continues to be a useful tool to study microbiome composition and dynamics, in part due to advances in next generation sequencing technology that translate into reductions in cost. Reliable taxonomic identification to the species-level, however, remains difficult, especially for short-read sequencing platforms, due to incomplete coverage of the 16S rRNA gene. This is especially true for Salmonella enterica, which is often found as a low abundant member of the microbial community, and is often found in combination with several other closely related enteric species. Here, we report on the evaluation and application of Resphera Insight, an ultra-high resolution taxonomic assignment algorithm for 16S rRNA sequences to the species level. The analytical pipeline achieved 99.7% sensitivity to correctly identify S. enterica from WGS datasets extracted from the FDA GenomeTrakr Bioproject, while demonstrating 99.9% specificity over other Enterobacteriaceae members. From low-diversity and low-complexity samples, namely ice cream, the algorithm achieved 100% specificity and sensitivity for Salmonella detection. As demonstrated using cilantro and chili powder, for highly complex and diverse samples, especially those that contain closely related species, the detection threshold will likely have to be adjusted higher to account for misidentifications. We also demonstrate the utility of this approach to detect Salmonella in the clinical setting, in this case, bloodborne infections.

  5. Portable laser speckle perfusion imaging system based on digital signal processor.

    Science.gov (United States)

    Tang, Xuejun; Feng, Nengyun; Sun, Xiaoli; Li, Pengcheng; Luo, Qingming

    2010-12-01

    The ability to monitor blood flow in vivo is of major importance in clinical diagnosis and in basic researches of life science. As a noninvasive full-field technique without the need of scanning, laser speckle contrast imaging (LSCI) is widely used to study blood flow with high spatial and temporal resolution. Current LSCI systems are based on personal computers for image processing with large size, which potentially limit the widespread clinical utility. The need for portable laser speckle contrast imaging system that does not compromise processing efficiency is crucial in clinical diagnosis. However, the processing of laser speckle contrast images is time-consuming due to the heavy calculation for enormous high-resolution image data. To address this problem, a portable laser speckle perfusion imaging system based on digital signal processor (DSP) and the algorithm which is suitable for DSP is described. With highly integrated DSP and the algorithm, we have markedly reduced the size and weight of the system as well as its energy consumption while preserving the high processing speed. In vivo experiments demonstrate that our portable laser speckle perfusion imaging system can obtain blood flow images at 25 frames per second with the resolution of 640 × 480 pixels. The portable and lightweight features make it capable of being adapted to a wide variety of application areas such as research laboratory, operating room, ambulance, and even disaster site.

  6. Utilizing dynamic laser speckle to probe nanoscale morphology evolution in nanoporous gold thin films.

    Science.gov (United States)

    Chapman, Christopher A R; Ly, Sonny; Wang, Ling; Seker, Erkin; Matthews, Manyalibo J

    2016-03-07

    This paper demonstrates the use of dynamic laser speckle autocorrelation spectroscopy in conjunction with the photothermal treatment of nanoporous gold (np-Au) thin films to probe nanoscale morphology changes during the photothermal treatment. Utilizing this spectroscopy method, backscattered speckle from the incident laser is tracked during photothermal treatment and both the characteristic feature size and annealing time of the film are determined. These results demonstrate that this method can successfully be used to monitor laser-based surface modification processes without the use of ex-situ characterization.

  7. Climate change and Mediterranean storm tracks: present and future climate simulations of a high-resolution Mediterranean model

    Science.gov (United States)

    Hatzaki, M.; Flocas, H. A.; Simmonds, I.; Keay, K.; Giannakopoulos, C.; Brikolas, V.; Kouroutzoglou, J.

    2010-09-01

    A number of studies suggest that cyclone activity over both hemispheres has changed over the second half of the 20th century. General features include a reduction in the number of cyclones but with an increase in the number of more intense cyclones; as well as a poleward shift in the tracks. Moreover, these features are expected to be projected in the future under global warming conditions. The assessment of the future changes of the cyclonic activity as imposed by global warming conditions is very important since these cyclones can be associated with extreme precipitation conditions, severe storms and floods. This is more important for the Mediterranean that has been found to be more vulnerable to climate change. The main objective of the current study is to better understand and assess future changes in the main characteristics of cyclonic tracks in the Mediterranean. The climatology of the cyclonic tracks includes temporal and spatial variations of frequency, and dynamic and kinematic parameters, such as intensity, size, propagation velocity, as well as trend analysis. For this purpose, the ENEA high resolution model is employed, based on PROTHEUS system composed of the RegCM atmospheric regional model and the MITgcm ocean model, coupled through the OASIS3 flux coupler. These model data became available through the EU Project CIRCE which aims to perform, for the first time, climate change projections with a realistic representation of the Mediterranean Sea. Two experiments are employed; a) the EH5OM_20C3M present climate simulation, where the lateral boundary conditions for the atmosphere (1951-2000) are taken from the ECHAM5-MPIOM 20c3m global simulation (run3) included in the IPCC-AR4, and b) the EH5OM_A1B scenario simulation, where the IPCC-AR4 ECHAM5-MPIOM SRESA1B global simulation (run3) has been used for the period 2001-2050. The identification and tracking of cyclones is performed with the aid of the Melbourne University algorithm (MS algorithm

  8. Electromagnetic tracking of handheld high-resolution endomicroscopy probes to assist with real-time video mosaicking

    Science.gov (United States)

    Vyas, Khushi; Hughes, Michael; Yang, Guang-Zhong

    2015-03-01

    Optical fiber bundle based endomicroscopy is a low-cost optical biopsy technique for in vivo cellular level imaging. A limitation of such an imaging system, however, is its small field-of-view (FOV), typically less than 1 mm2. With such a small FOV it is difficult to associate individual image frames with the larger scale anatomical structure. Video-sequence mosaicking algorithms have been proposed as a solution for increasing the image FOV while maintaining cellular-level resolution by stitching together the endomicroscopy images. Although extensive research has focused on image processing and mosaicking algorithms, there has been limited work on localization of the probe to assist with building high quality mosaics over large areas of tissue. In this paper, we propose the use of electromagnetic (EM) navigation to assist with large-area mosaicking of hand-held high-resolution endomicroscopy probes. A six degree-of-freedom EM sensor is used to track in real-time the position and orientation of the tip of the imaging probe during free-hand scanning. We present a proof-of-principle system for EM-video data co-calibration and registration and then describe a two-step image registration algorithm that assists mosaic reconstruction. Preliminary experimental investigations are carried out on phantoms and ex vivo porcine tissue for free-hand scanning. The results demonstrate that the proposed methodology significantly improves the quality and accuracy of reconstructed mosaics compared to reconstructions based only on conventional pair-wise image registration. In principle, this approach can be applied to other optical biopsy techniques such as confocal endomicroscopy and endocytoscopy.

  9. Simulations of x-ray speckle-based dark-field and phase-contrast imaging with a polychromatic beam

    Energy Technology Data Exchange (ETDEWEB)

    Zdora, Marie-Christine, E-mail: marie-christine.zdora@diamond.ac.uk [Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748 Garching (Germany); Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom); Department of Physics & Astronomy, University College London, London WC1E 6BT (United Kingdom); Thibault, Pierre [Department of Physics & Astronomy, University College London, London WC1E 6BT (United Kingdom); Pfeiffer, Franz [Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748 Garching (Germany); Zanette, Irene [Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748 Garching (Germany); Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom)

    2015-09-21

    Following the first experimental demonstration of x-ray speckle-based multimodal imaging using a polychromatic beam [I. Zanette et al., Phys. Rev. Lett. 112(25), 253903 (2014)], we present a simulation study on the effects of a polychromatic x-ray spectrum on the performance of this technique. We observe that the contrast of the near-field speckles is only mildly influenced by the bandwidth of the energy spectrum. Moreover, using a homogeneous object with simple geometry, we characterize the beam hardening artifacts in the reconstructed transmission and refraction angle images, and we describe how the beam hardening also affects the dark-field signal provided by speckle tracking. This study is particularly important for further implementations and developments of coherent speckle-based techniques at laboratory x-ray sources.

  10. Ex-situ tracking solid oxide cell electrode microstructural evolution in a redox cycle by high resolution ptychographic nanotomography

    Science.gov (United States)

    De Angelis, Salvatore; Jørgensen, Peter Stanley; Esposito, Vincenzo; Tsai, Esther Hsiao Rho; Holler, Mirko; Kreka, Kosova; Abdellahi, Ebtisam; Bowen, Jacob R.

    2017-08-01

    For solid oxide fuel and electrolysis cells, precise tracking of 3D microstructural change in the electrodes during operation is considered critical to understand the complex relationship between electrode microstructure and performance. Here, for the first time, we report a significant step towards this aim by visualizing a complete redox cycle in a solid oxide cell (SOC) electrode. The experiment demonstrates synchrotron-based ptychography as a method of imaging SOC electrodes, providing an unprecedented combination of 3D image quality and spatial resolution among non-destructive imaging techniques. Spatially registered 3D reconstructions of the same location in the electrode clearly show the evolution of the microstructure from the pristine state to the oxidized state and to the reduced state. A complete mechanical destruction of the zirconia backbone is observed via grain boundary fracture, the nickel and pore networks undergo major reorganization and the formation of internal voids is observed in the nickel-oxide particles after the oxidation. These observations are discussed in terms of reaction kinetics, electrode mechanical stress and the consequences of redox cycling on electrode performance.

  11. Twinkle Twinkle Little Star - Speckle Imaging for Exoplanet Characterization

    Science.gov (United States)

    Howell, Steve B.; Scott, Nic; Horch, Elliott

    2016-06-01

    The NASA K2 mission is finding many high-value exoplanets and world-wide follow-up is ensuing. The NASA TESS mission will soon be launched, requiring additional ground-based observations as well. As a part of the NASA-NSFNN-EXPLORE program to enable exoplanet research, our group is building two new speckle interferometry cameras for the Kitt Peak WIYN 3.5-m telescope and the Gemini-N 8-m telescope. Modeled after the successful DSSI visitor instrument that has been used at these telescopes for many years, speckle observations provide the highest resolution images available today from any ground- or space-based single telescope. They are the premier method through which small, rocky exoplanets can be validated. Available for public use in early 2017, WIYNSPKL and GEMSPKL will obtain simultaneous images in two filters with fast EMCCD readout, "speckle" and “wide-field” imaging modes, and user support for proposal writing, observing, and data reduction. We describe the new cameras, their design, and their benefits for exoplanet follow-up, characterization, and validation. Funding for this project comes from the NASA Exoplanet Exploration Program and NASA HQ.

  12. Gold-Speckled Multimodal Nanoparticles for Noninvasive Bioimaging

    Science.gov (United States)

    2008-01-01

    In this report the synthesis, characterization, and functional evaluation of a multimodal nanoparticulate contrast agent for noninvasive imaging through both magnetic resonance imaging (MRI) and photoacoustic tomography (PAT) is presented. The nanoparticles described herein enable high resolution and highly sensitive three-dimensional diagnostic imaging through the synergistic coupling of MRI and PAT capabilities. Gadolinium (Gd)-doped gold-speckled silica (GSS) nanoparticles, ranging from 50 to 200 nm, have been prepared in a simple one-pot synthesis using nonionic microemulsions. The photoacoustic signal is generated from a nonuniform, discontinuous gold nanodomains speckled across the silica surface, whereas the MR contrast is provided through Gd incorporated in the silica matrix. The presence of a discontinuous speckled surface, as opposed to a continuous gold shell, allows sufficient bulk water exchange with the Gd ions to generate a strong MR contrast. The dual imaging capabilities of the particles have been demonstrated through in silicio and in vitro methods. The described particles also have the capacity for therapeutic applications including the thermal ablation of tumors through the absorption of irradiated light. PMID:19466201

  13. Speckle suppression in scanning laser display.

    Science.gov (United States)

    Yurlov, Victor; Lapchuk, Anatoly; Yun, Sangkyeong; Song, Jonghyeong; Yang, Haengseok

    2008-01-10

    The theory of speckle noise in a scanning beam is presented. The general formulas for the calculation of speckle contrast, which apply to any scanning display, are obtained. It is shown that the main requirement for successful speckle suppression in a scanning display is a narrow autocorrelation peak and low sidelobe level in the autocorrelation function of the complex amplitude distribution across a scanning light beam. The simple formulas for speckle contrast for a beam with a narrow autocorrelation function peak were obtained. It was shown that application of a diffractive optical element (DOE) with a Barker code phase shape could use only natural display scanning motion for speckle suppression. DOE with a Barker code phase shape has a small size and may be deposited on the light modulator inside the depth of the focus of the reflected beam area, and therefore, it does not need an additional image plane and complicated relay optics.

  14. Astronomical Observations by Speckle Interferometry.

    Science.gov (United States)

    1986-06-12

    NUMBER ORGANIZATION O osf appi)81-061 %A mc’S z &I -- St ADRES (ft, Stat. &WCode) 10. SOURCE OF FUNDING NUMBERS C1X1’Z"/A~N ~ ~rf.. PROGRAM IPROJECT...34Masses and Luminosities of the Giant Spectroscopic/Speckle Interferometric Binaries Gamma Persei and Phi Cygni" H.A. McAlister, THE ASTRONOMICAL JOURNAL...Topical Meeting on Information Processing in Astronomy and Optics sponsored by the American Astronomical Society and the Optical Society of America, St

  15. NESSI and `Alopeke: Two new dual-channel speckle imaging instruments

    Science.gov (United States)

    Scott, Nicholas J.

    2018-01-01

    NESSI and `Alopeke are two new speckle imagers built at NASA's Ames Research Center for community use at the WIYN and Gemini telescopes, respectively. The two instruments are functionally similar and include the capability for wide-field imaging in additional to speckle interferometry. The diffraction-limited imaging available through speckle effectively eliminates distortions due to the presence of Earth's atmosphere by `freezing out' changes in the atmosphere by taking extremely short exposures and combining the resultant speckles in Fourier space. This technique enables angular resolutions equal to the theoretical best possible for a given telescope, effectively giving space-based resolution from the ground. Our instruments provide the highest spatial resolution available today on any single aperture telescope.A primary role of these instruments is exoplanet validation for the Kepler, K2, TESS, and many RV programs. Contrast ratios of 6 or more magnitudes are easily obtained. The instrument uses two emCCD cameras providing simultaneous dual-color observations help to characterize detected companions. High resolution imaging enables the identification of blended binaries that contaminate many exoplanet detections, leading to incorrectly measured radii. In this way small, rocky systems, such as Kepler-186b and the TRAPPIST-1 planet family, may be validated and thus the detected planets radii are correctly measured.

  16. Sparsity assisted approach for imaging from laser speckle

    Science.gov (United States)

    Vinu, R. V.; Gaur, Charu; Khare, Kedar; Singh, Rakesh Kumar

    2017-02-01

    A non-interferometric technique for imaging from laser speckle using speckle autocorrelation assisted with sparsity enhanced iterative phase reconstruction is proposed and demonstrated in this paper. The use of sparsity assisted approach in combination with speckle correlation provides the potential to retrieve the complex correlation function from random speckle pattern. Imaging through random scattering medium is demonstrated by recovery of a circular and an annular aperture from the laser speckle.

  17. Near-field to far-field characterization of speckle patterns generated by disordered nanomaterials

    CERN Document Server

    Parigi, Valentina; Binard, Guillaume; Bourdillon, Céline; Maître, Agnès; Carminati, Rémi; Krachmalnicoff, Valentina; De Wilde, Yannick

    2016-01-01

    We study the intensity spatial correlation function of optical speckle patterns above a disordered dielectric medium in the multiple scattering regime. The intensity distributions are recorded by scanning near-field optical microscopy (SNOM) with sub-wavelength spatial resolution at variable distances from the surface in a range which spans continuously from the near-field (distance $ \\ll \\lambda $) to the far-field regime (distance $\\gg \\lambda $). The non-universal behavior at sub-wavelength distances reveals the connection between the near-field speckle pattern and the internal structure of the medium.

  18. Feasibility study: protein denaturation and coagulation monitoring with speckle variance optical coherence tomography

    Science.gov (United States)

    Lee, Changho; Cheon, Gyeongwoo; Kim, Do-Hyun; Kang, Jin U.

    2016-12-01

    We performed the feasibility study using speckle variance optical coherence tomography (SvOCT) to monitor the thermally induced protein denaturation and coagulation process as a function of temperature and depth. SvOCT provided the depth-resolved image of protein denaturation and coagulation with microscale resolution. This study was conducted using egg white. During the heating process, as the temperature increased, increases in the speckle variance signal was observed as the egg white proteins coagulated. Additionally, by calculating the cross-correlation coefficient in specific areas, denaturized egg white conditions were successfully estimated. These results indicate that SvOCT could be used to monitor the denaturation process of various proteins.

  19. Near-field to far-field characterization of speckle patterns generated by disordered nanomaterials.

    Science.gov (United States)

    Parigi, Valentina; Perros, Elodie; Binard, Guillaume; Bourdillon, Céline; Maître, Agnès; Carminati, Rémi; Krachmalnicoff, Valentina; De Wilde, Yannick

    2016-04-04

    We study the intensity spatial correlation function of optical speckle patterns above a disordered dielectric medium in the multiple scattering regime. The intensity distributions are recorded by scanning near-field optical microscopy (SNOM) with sub-wavelength spatial resolution at variable distances from the surface in a range which spans continuously from the near-field (distance ≪ λ) to the far-field regime (distance ≫ λ). The non-universal behavior at sub-wavelength distances reveals the connection between the near-field speckle pattern and the internal structure of the medium.

  20. Speckle Interferometry at SOAR in 2014

    Science.gov (United States)

    Tokovinin, Andrei; Mason, Brian D.; Hartkopf, William I.; Mendez, Rene A.; Horch, Elliott P.

    2015-08-01

    The results of speckle interferometric observations at the Southern Astrophysical Research Telescope (SOAR) telescope in 2014 are given. A total of 1641 observations were taken, yielding 1636 measurements of 1218 resolved binary and multiple stars and 577 non-resolutions of 441 targets. We resolved for the first time 56 pairs, including some nearby astrometric or spectroscopic binaries and ten new subsystems in previously known visual binaries. The calibration of the data is checked by linear fits to the positions of 41 wide binaries observed at SOAR over several seasons. The typical calibration accuracy is 0.°1 in angle and 0.3% in pixel scale, while the measurement errors are on the order of 3 mas. The new data are used here to compute 194 binary star orbits, 148 of which are improvements on previous orbital solutions and 46 are first-time orbits. Based on observations obtained at the Southern Astrophysical Research (SOAR) telescope, which is a joint project of the Ministério da Ciência, Tecnologia, e Inovação (MCTI) da República Federativa do Brasil, the U.S. National Optical Astronomy Observatory (NOAO), the University of North Carolina at Chapel Hill (UNC), and Michigan State University (MSU).

  1. Advances in speckle metrology and related techniques

    CERN Document Server

    Kaufmann, Guillermo H

    2010-01-01

    Speckle metrology includes various optical techniques that are based on the speckle fields generated by reflection from a rough surface or by transmission through a rough diffuser. These techniques have proven to be very useful in testing different materials in a non-destructive way. They have changed dramatically during the last years due to the development of modern optical components, with faster and more powerful digital computers, and novel data processing approaches. This most up-to-date overview of the topic describes new techniques developed in the field of speckle metrology over the l

  2. Reduced speckle noise on medical ultrasound images using cellular neural network.

    Science.gov (United States)

    Park, Hyunkyung; Nishimura, Toshihiro

    2007-01-01

    Speckle noise is indispensable get from ultrasound image. In general tends to reduce the image resolution and contrast. In addition to the doctor diagnosis, is lacking for judgment accuracy. This paper is reduced the speckle noise and enhanced boundary of a tumor in the medical ultrasound images. The proposed method is valuated using numerical phantom simulating ultrasound B-mode images, and the effect is confirmed by applying to medical ultrasound images. Therefore, some important features such as tissue boundaries and small tumors may be overlooked. A cellular neural network which is a kind of recurrent neural network can deal with images by the weight of neurons called a cell. It could be obtained more detail images recognition compared with the previous studies. Determination template parameters of the cellular neural network for ultrasound image processing are discussed. The experimental results show effectiveness of applying the proposed method to boundary enhancement and the speckle noise reduction of medical ultrasound image.

  3. Effect of static scatterers in laser speckle contrast imaging: an experimental study on correlation and contrast.

    Science.gov (United States)

    Vaz, Pedro Guilherme; Humeau-Heurtier, Anne; Figueiras, Edite; Correia, Carlos; Cardoso, Joao M R

    2017-12-05

    Laser speckle contrast imaging (LSCI) is a non-invasive microvascular blood flow assessment technique with good temporal and spatial resolutions. Most LSCI systems, including commercials devices, can only perform qualitative blood flow evaluation which is a major limitation of this technique. There are several factors that prevent LSCI to be a quantitative technique. Among these factors we can highlight the effect of static scatterers. The goal of this work was to study the influence of different static and dynamic scatterers concentrations on laser speckle correlation and contrast. In order to achieve this, a laser speckle prototype was developed and tested using an optical phantom with different concentrations of static and dynamic scatterers. It has been found that the laser speckle correlation can be used to estimate the relative concentration of static/dynamic scatterers within a sample. Moreover, the speckle correlation proved to be independent of the dynamic scatterers velocity which is a fundamental characteristic to be used as contrast correction method. Creative Commons Attribution license.

  4. Line and boundary detection in speckle images.

    Science.gov (United States)

    Czerwinski, R N; Jones, D L; O'Brien, W R

    1998-01-01

    This paper considers the problem of detecting lines in speckle imagery, such as that produced by synthetic aperture radar (SAR) or ultrasound techniques. Using the physical principles that account for the speckle phenomenon, we derive the optimal detector for lines in fully developed speckle, and we compare the optimal detector to several suboptimal detection rules that are more computationally efficient. We show that when the noise is uncorrelated, a very simple suboptimal detection rule is nearly optimal, and that even in colored speckle, a related class of detectors can approach optimal performance. Finally, we also discuss the application of this technique to medical ultrasonic images, where the detection of tissue boundaries is considered as a problem of line detection.

  5. Speckle Interferometry with Amateur-Class Equipment

    Science.gov (United States)

    Harshaw, Richard; Wuthrich, Ethan; Dolbear, Kyle

    2015-05-01

    The relatively young field of speckle interferometry of close double stars has up to now been the domain of large telescopes and expensive scientific CCD cameras. With the advent of relatively inexpensive and high-performance CCD cameras, the domain of speckle interferometry has been extended into the serious amateur realm allowing amateurs with equipment as small as 8-inches aperture to do actual speckle analysis of binary star systems. This paper describes the work of one such team of amateur astronomers and students as part of their course work for an on-line scientific research experience course provided on-line by Cuesta College of San Luis Obispo, California. An explanation of speckle and how it works is followed by a discussion of how the camera was calibrated, then a discussion of the research methodology. Results of calibration and double star measurements are then given and implications of the process and results discussed.

  6. Early detection and treatment of Speckled leukoplakia

    OpenAIRE

    Selviana Tampoma; Iwan Hernawan

    2016-01-01

    Background: Leukoplakia is one of potentially malignant disorders that can be found on oral mucosa. Speckled leukoplakia is a rare type of leukoplakia with a very high risk of premalignant growth. Approximately 3 % of worldwide population has suffered from leukoplakia, 5-25% of which tend to be malignant leukoplakia. Purpose: This case report was aimed to discuss about early detection of speckled leukoplakia as one of potentially malignant disorders. Case: A 62 year old male patient came with...

  7. Statistics of polarization speckle: theory versus experiment

    DEFF Research Database (Denmark)

    Wang, Wei; Hanson, Steen Grüner; Takeda, Mitsuo

    2010-01-01

    In this paper, we reviewed our recent work on the statistical properties of polarization speckle, described by stochastic Stokes parameters fluctuating in space. Based on the Gaussian assumption for the random electric field components and polar-interferometer, we investigated theoretically...... and experimentally the statistics of Stokes parameters of polarization speckle, including probability density function of Stokes parameters with the spatial degree of polarization, autocorrelation of Stokes vector and statistics of spatial derivatives for Stokes parameters....

  8. Box fractal dimension in speckle images

    Science.gov (United States)

    Rabal, Héctor; Grumel, Eduardo; Cap, Nelly; Buffarini, Leandro; Trivi, Marcelo

    2017-06-01

    In this paper, we propose a generalization of the box fractal dimension in images by considering the curve obtained from its value as a function of the binarization threshold. This curve can be used to describe speckle patterns. We show some examples of both objective simulated and experimental and subjective speckle in some cases of interest. The concept can be extended for all types of images.

  9. Distance measurements by speckle correlation of objective speckle patterns, structured by the illumination

    DEFF Research Database (Denmark)

    Jakobsen, Michael Linde; Hanson, Steen Grüner

    2012-01-01

    Objective speckles produced by two beams overlapping and interfering on a rough object surface contain information about the angle of incidence of the two beams, and how well they overlap. We obtain the autocovariance function for such a speckle pattern, and demonstrate how the information carrie...

  10. Storm Identification, Tracking and Forecasting Using High-Resolution Images of Short-Range X-Band Radar

    Directory of Open Access Journals (Sweden)

    Sajid Shah

    2015-05-01

    Full Text Available Rain nowcasting is an essential part of weather monitoring. It plays a vital role in human life, ranging from advanced warning systems to scheduling open air events and tourism. A nowcasting system can be divided into three fundamental steps, i.e., storm identification, tracking and nowcasting. The main contribution of this work is to propose procedures for each step of the rain nowcasting tool and to objectively evaluate the performances of every step, focusing on two-dimension data collected from short-range X-band radars installed in different parts of Italy. This work presents the solution of previously unsolved problems in storm identification: first, the selection of suitable thresholds for storm identification; second, the isolation of false merger (loosely-connected storms; and third, the identification of a high reflectivity sub-storm within a large storm. The storm tracking step of the existing tools, such as TITANand SCIT, use only up to two storm attributes, i.e., center of mass and area. It is possible to use more attributes for tracking. Furthermore, the contribution of each attribute in storm tracking is yet to be investigated. This paper presents a novel procedure called SALdEdA (structure, amplitude, location, eccentricity difference and areal difference for storm tracking. This work also presents the contribution of each component of SALdEdA in storm tracking. The second order exponential smoothing strategy is used for storm nowcasting, where the growth and decay of each variable of interest is considered to be linear. We evaluated the major steps of our method. The adopted techniques for automatic threshold calculation are assessed with a 97% goodness. False merger and sub-storms within a cluster of storms are successfully handled. Furthermore, the storm tracking procedure produced good results with an accuracy of 99.34% for convective events and 100% for stratiform events.

  11. Image Enhancement and Speckle Reduction of Full Polarimetric SAR Data by Gaussian Markov Random Field

    Science.gov (United States)

    Mahdian, M.; Motagh, M.; Akbari, V.

    2013-09-01

    In recent years, the use of Polarimetric Synthetic Aperture Radar (PolSAR) data in different applications dramatically has been increased. In SAR imagery an interference phenomenon with random behavior exists which is called speckle noise. The interpretation of data encounters some troubles due to the presence of speckle which can be considered as a multiplicative noise affecting all coherent imaging systems. Indeed, speckle degrade radiometric resolution of PolSAR images, therefore it is needful to perform speckle filtering on the SAR data type. Markov Random Field (MRF) has proven to be a powerful method for drawing out eliciting contextual information from remotely sensed images. In the present paper, a probability density function (PDF), which is fitted well with the PolSAR data based on the goodness-of-fit test, is first obtained for the pixel-wise analysis. Then the contextual smoothing is achieved with the MRF method. This novel speckle reduction method combines an advanced statistical distribution with spatial contextual information for PolSAR data. These two parts of information are combined based on weighted summation of pixel-wise and contextual models. This approach not only preserves edge information in the images, but also improves signal-to-noise ratio of the results. The method maintains the mean value of original signal in the homogenous areas and preserves the edges of features in the heterogeneous regions. Experiments on real medium resolution ALOS data from Tehran, and also high resolution full polarimetric SAR data over the Oberpfaffenhofen test-site in Germany, demonstrate the effectiveness of the algorithm compared with well-known despeckling methods.

  12. Speckle perception and disturbance limit in laser based projectors

    Science.gov (United States)

    Verschaffelt, Guy; Roelandt, Stijn; Meuret, Youri; Van den Broeck, Wendy; Kilpi, Katriina; Lievens, Bram; Jacobs, An; Janssens, Peter; Thienpont, Hugo

    2016-04-01

    We investigate the level of speckle that can be tolerated in a laser cinema projector. For this purpose, we equipped a movie theatre room with a prototype laser projector. A group of 186 participants was gathered to evaluate the speckle perception of several, short movie trailers in a subjective `Quality of Experience' experiment. This study is important as the introduction of lasers in projection systems has been hampered by the presence of speckle in projected images. We identify a speckle disturbance threshold by statistically analyzing the observers' responses for different values of the amount of speckle, which was monitored using a well-defined speckle measurement method. The analysis shows that the speckle perception of a human observer is not only dependent on the objectively measured amount of speckle, but it is also strongly influenced by the image content. As is also discussed in [Verschaffelt et al., Scientific Reports 5, art. nr. 14105, 2015] we find that, for moving images, the speckle becomes disturbing if the speckle contrast becomes larger than 6.9% for the red, 6.0% for the green, and 4.8% for the blue primary colors of the projector, whereas for still images the speckle detection threshold is about 3%. As we could not independently tune the speckle contrast of each of the primary colors, this speckle disturbance limit seems to be determined by the 6.9% speckle contrast of the red color as this primary color contains the largest amount of speckle. The speckle disturbance limit for movies thus turns out to be substantially larger than that for still images, and hence is easier to attain.

  13. Photothermal speckle modulation for noncontact materials characterization.

    Science.gov (United States)

    Stolyarov, Alexander M; Sullenberger, Ryan M; Crompton, David R; Jeys, Thomas H; Saar, Brian G; Herzog, William D

    2015-12-15

    We have developed a noncontact, photothermal materials characterization method based on visible-light speckle imaging. This technique is applied to remotely measure the infrared absorption spectra of materials and to discriminate materials based on their thermal conductivities. A wavelength-tunable (7.5-8.7 μm), intensity-modulated, quantum cascade pump laser and a continuous-wave 532 nm probe laser illuminate a sample surface such that the two laser spots overlap. Surface absorption of the intensity-modulated pump laser induces a time-varying thermoelastic surface deformation, resulting in a time-varying 532 nm scattering speckle field from the surface. The speckle modulation amplitude, derived from a series of visible camera images, is found to correlate with the amplitude of the surface motion. By tuning the pump laser's wavelength over a molecular absorption feature, the amplitude spectrum of the speckle modulation is found to correlate to the IR absorption spectrum. As an example, we demonstrate this technique for spectroscopic identification of thin polymeric films. Furthermore, by adjusting the rate of modulation of the pump beam and measuring the associated modulation transfer to the visible speckle pattern, information about the thermal time constants of surface and sub-surface features can be revealed. Using this approach, we demonstrate the ability to distinguish between different materials (including metals, semiconductors, and insulators) based on differences in their thermal conductivities.

  14. ISED: Constructing a high-resolution elevation road dataset from massive, low-quality in-situ observations derived from geosocial fitness tracking data.

    Directory of Open Access Journals (Sweden)

    Grant McKenzie

    Full Text Available Gaining access to inexpensive, high-resolution, up-to-date, three-dimensional road network data is a top priority beyond research, as such data would fuel applications in industry, governments, and the broader public alike. Road network data are openly available via user-generated content such as OpenStreetMap (OSM but lack the resolution required for many tasks, e.g., emergency management. More importantly, however, few publicly available data offer information on elevation and slope. For most parts of the world, up-to-date digital elevation products with a resolution of less than 10 meters are a distant dream and, if available, those datasets have to be matched to the road network through an error-prone process. In this paper we present a radically different approach by deriving road network elevation data from massive amounts of in-situ observations extracted from user-contributed data from an online social fitness tracking application. While each individual observation may be of low-quality in terms of resolution and accuracy, taken together they form an accurate, high-resolution, up-to-date, three-dimensional road network that excels where other technologies such as LiDAR fail, e.g., in case of overpasses, overhangs, and so forth. In fact, the 1m spatial resolution dataset created in this research based on 350 million individual 3D location fixes has an RMSE of approximately 3.11m compared to a LiDAR-based ground-truth and can be used to enhance existing road network datasets where individual elevation fixes differ by up to 60m. In contrast, using interpolated data from the National Elevation Dataset (NED results in 4.75m RMSE compared to the base line. We utilize Linked Data technologies to integrate the proposed high-resolution dataset with OpenStreetMap road geometries without requiring any changes to the OSM data model.

  15. ISED: Constructing a high-resolution elevation road dataset from massive, low-quality in-situ observations derived from geosocial fitness tracking data.

    Science.gov (United States)

    McKenzie, Grant; Janowicz, Krzysztof

    2017-01-01

    Gaining access to inexpensive, high-resolution, up-to-date, three-dimensional road network data is a top priority beyond research, as such data would fuel applications in industry, governments, and the broader public alike. Road network data are openly available via user-generated content such as OpenStreetMap (OSM) but lack the resolution required for many tasks, e.g., emergency management. More importantly, however, few publicly available data offer information on elevation and slope. For most parts of the world, up-to-date digital elevation products with a resolution of less than 10 meters are a distant dream and, if available, those datasets have to be matched to the road network through an error-prone process. In this paper we present a radically different approach by deriving road network elevation data from massive amounts of in-situ observations extracted from user-contributed data from an online social fitness tracking application. While each individual observation may be of low-quality in terms of resolution and accuracy, taken together they form an accurate, high-resolution, up-to-date, three-dimensional road network that excels where other technologies such as LiDAR fail, e.g., in case of overpasses, overhangs, and so forth. In fact, the 1m spatial resolution dataset created in this research based on 350 million individual 3D location fixes has an RMSE of approximately 3.11m compared to a LiDAR-based ground-truth and can be used to enhance existing road network datasets where individual elevation fixes differ by up to 60m. In contrast, using interpolated data from the National Elevation Dataset (NED) results in 4.75m RMSE compared to the base line. We utilize Linked Data technologies to integrate the proposed high-resolution dataset with OpenStreetMap road geometries without requiring any changes to the OSM data model.

  16. Acoustical simulation based on head-tracked auralization and measured high-resolution head related transfer function (HRTF) and impulse responses

    Science.gov (United States)

    Ahnert, Wolfgang; Feistel, Stefan; Moldrzyk, Christoph

    2004-10-01

    A very desirable feature of modern acoustical simulation programs is the easy, fast and reliable auralization of the prediction results. In this paper we consider a new auralization method, based on a head-tracked headphone system with high spatial resolution and real-time convolution. We discuss the way to measure the directional head-related transfer functions, the calculation of the directional binaural impulse responses and the realization as a real-time convolution software. Furthermore, high-resolution impulse responses have been measured to compare reality, measurement and prediction results of an example room. The measurements were performed with a newly developed software tool EASERA. We conclude that, using this new method, auralization results are obtained equivalent to the human perception in reality.

  17. Using speckle to measure tissue dispersion in optical coherence tomography

    Science.gov (United States)

    Photiou, Christos; Bousi, Evgenia; Zouvani, Ioanna; Pitris, Costas

    2017-02-01

    In Optical Coherence tomography (OCT), dispersion mismatches cause degradation of the image resolution. However, dispersion is specific to the material that is causing the effect and can therefore carry useful information regarding the composition of the samples. In this summary, we propose a novel technique for estimating the dispersion in tissue which uses the image speckle to calculate the PSF degradation and is therefore applicable to any tissue and can be implemented in vivo and in situ. A Wiener-type deconvolution algorithm was used to estimate the image PSF degradation from the speckle. The proposed method was verified ex vivo resulting in comparable values of the Group Velocity Dispersion (GVD) as obtained by a standard estimation technique described in the literature. The applicability to cancer diagnosis was evaluated on a small set of gastrointestinal normal and cancer OCT images. Using the statistics of the GVD estimate, the tissue classification resulted in 93% sensitivity and 73% specificity (84% correct classification rate). The success of these preliminary results indicates the potential of the proposed method which should be further investigated to elucidate its advantages and limitations.

  18. Dynamic speckle study of microbial growth

    Science.gov (United States)

    Vincitorio, F. M.; Mulone, C.; Marcuzzi, P. A.; Budini, N.; Freyre, C.; Lopez, A. J.; Ramil, A.

    2015-08-01

    In this work we present a characterization of yeast dynamic speckle activity during growth in an isolated agar culture medium. We found that it is possible to detect the growth of the microorganisms even before they turn out to be visible. By observing the time evolution of the speckle activity at different regions of the culture medium we could extract a map of the growth process, which served to analyze how the yeast develops and spreads over the agar's medium. An interesting point of this study concerns with the influence of the laser light on the yeast growth rate. We have found that yeast finds hard to develop at regions with higher laser light illumination, although we used a synchronous system to capture the speckle pattern. The results obtained in this work would serve us as a starting point to fabricate a detector of growing microorganism colonies, with obvious interesting applications in diverse areas.

  19. Bayesian Speckle Tracking. Part II: Biased Ultrasound Displacement Estimation

    Science.gov (United States)

    Byram, Brett; Trahey, Gregg E.; Palmeri, Mark

    2012-01-01

    Ultrasonic displacement estimates have numerous clinical uses including blood-flow, elastography, therapeutic guidance and ARFI imaging. These clinical tasks could be improved with better ultrasonic displacement estimates. Traditional ultrasonic displacement estimates are limited by the Cramer-Rao lower bound (CRLB). The CRLB can be surpassed using biased estimates. In this paper a framework for biased estimation using Bayes’ theorem is described. The Bayesian displacement estimation method is tested against simulations of several common types of motion: bulk, step, compression, and acoustic radiation force induced motion. Bayesian estimation is also applied to in vivo acoustic radiation force imaging of cardiac ablation lesions. The Bayesian estimators are compared to the unbiased estimator, normalized cross-correlation. As an example, the peak displacement of the simulated acoustic radiation force response is reported since this position results in the noisiest estimates. Estimates were made with a 1.5 λ kernel and 20 dB SNR on 100 data realizations. Estimates using normalized cross-correlation and the Bayes’ estimator had mean-square errors of 17 and 7.6 μm2, respectively, and contextualized by the true displacement magnitude, 10.9 μm. Biases for normalized cross-correlation and the Bayes’ estimator are −.12 and −.28 μm, respectively. In vivo results show qualitative improvements. The results show that with small amounts of additional information significantly improved performance can be realized. PMID:23287921

  20. Speckle reduction of OCT images using an adaptive cluster-based filtering

    Science.gov (United States)

    Adabi, Saba; Rashedi, Elaheh; Conforto, Silvia; Mehregan, Darius; Xu, Qiuyun; Nasiriavanaki, Mohammadreza

    2017-02-01

    Optical coherence tomography (OCT) has become a favorable device in the dermatology discipline due to its moderate resolution and penetration depth. OCT images however contain grainy pattern, called speckle, due to the broadband source that has been used in the configuration of OCT. So far, a variety of filtering techniques is introduced to reduce speckle in OCT images. Most of these methods are generic and can be applied to OCT images of different tissues. In this paper, we present a method for speckle reduction of OCT skin images. Considering the architectural structure of skin layers, it seems that a skin image can benefit from being segmented in to differentiable clusters, and being filtered separately in each cluster by using a clustering method and filtering methods such as Wiener. The proposed algorithm was tested on an optical solid phantom with predetermined optical properties. The algorithm was also tested on healthy skin images. The results show that the cluster-based filtering method can reduce the speckle and increase the signal-to-noise ratio and contrast while preserving the edges in the image.

  1. Simple Educational Tool for Digital Speckle Shearography

    Science.gov (United States)

    Spagnolo, Giuseppe Schirripa; Martocchia, Andrea; Papalillo, Donato; Cozzella, Lorenzo

    2012-01-01

    In this study, an educational tool has been prepared for obtaining short-term and more economic training on digital speckle shearography (DSS). Shearography non-destructive testing (NDT) has gained wide acceptance over the last decade, providing a number of important and exciting inspection solutions in aerospace, electronics and medical device…

  2. Optical configuration of pigmented lesion detection by frequency analysis of skin speckle patterns

    Science.gov (United States)

    Bishitz, Yael; Ozana, Nisan; Schwarz, Ariel; Beiderman, Yevgeny; Garcia, Javier; Zalevsky, Zeev

    2016-01-01

    In this paper we present a novel approach of realizing a safe, simple, and inexpensive sensor applicable to pigmented lesions detection. The approach is based on temporal tracking of back-reflected secondary speckle patterns generated while illuminating the affected area with a laser and applying periodic pressure to the surface via a controlled vibration source. When applied to pigmented lesions, the technique is superior to visual examination in avoiding many false positives and resultant unnecessary biopsies. Applying a series of different vibration frequencies at the examined tissue and analyzing the 2-D time varying speckle patterns in response to the applied periodic pressure creates a unique signature for each and different pigmented lesion. Analyzing these signatures is the first step toward detection of malignant melanoma. In this paper we present preliminary experiments that show the validity of the developed sensor for the classification of pigmented lesions. PMID:27231603

  3. The Track of Brain Activity during the Observation of TV Commercials with the High-Resolution EEG Technology

    OpenAIRE

    Astolfi, Laura; Vecchiato, Giovanni; De Vico Fallani, Fabrizio; Salinari, Serenella; Cincotti, Febo; Aloise, Fabio; Mattia, Donatella; Marciani, Maria Grazia; Bianchi, Luigi; Soranzo, Ramon; Babiloni, Fabio

    2009-01-01

    We estimate cortical activity in normal subjects during the observation of TV commercials inserted within a movie by using high-resolution EEG techniques. The brain activity was evaluated in both time and frequency domains by solving the associate inverse problem of EEG with the use of realistic head models. In particular, we recover statistically significant information about cortical areas engaged by particular scenes inserted within the TV commercial proposed with respect to the brain acti...

  4. Track parameter resolution study of a pixel only detector for LHC geometry and future high rate experiments

    Energy Technology Data Exchange (ETDEWEB)

    Blago, Michele Piero; Kar, Tamasi Rameshchandra; Schoening, Andre [Physikalisches Institut, Universitaet Heidelberg (Germany)

    2016-07-01

    Recent progress in pixel detector technology, for example using High Voltage-Monolithic Pixel Sensors (HV-MAPS), makes it feasible to construct an all-silicon pixel detector for large scale particle experiments like ATLAS and CMS or other future collider experiments. Preliminary studies have shown that nine layers of pixel sensors are sufficient to reliably reconstruct particle trajectories. The performance of such an all-pixel detector is studied based on a full GEANT simulation for high luminosity conditions at the upgraded LHC. Furthermore, the ability of an all-pixel detector to form trigger decisions using a special triplet pixel layer design is studied. Such a design could be used to reconstruct all tracks originating from the proton-proton interaction at the first hardware level at 40 MHz collision frequency.

  5. The journey of integrins and partners in a complex interactions landscape studied by super-resolution microscopy and single protein tracking

    Energy Technology Data Exchange (ETDEWEB)

    Rossier, Olivier; Giannone, Grégory [Univ. Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, F-33000 Bordeaux (France); CNRS, Interdisciplinary Institute for Neuroscience, UMR 5297, F-33000 Bordeaux (France)

    2016-04-10

    Cells adjust their adhesive and cytoskeletal organizations according to changes in the biochemical and physical nature of their surroundings. In return, by adhering and generating forces on the extracellular matrix (ECM) cells organize their microenvironment. Integrin-dependent focal adhesions (FAs) are the converging zones integrating biochemical and biomechanical signals arising from the ECM and the actin cytoskeleton. Thus, integrin-mediated adhesion and mechanotransduction, the conversion of mechanical forces into biochemical signals, are involved in critical cellular functions such as migration, proliferation and differentiation, and their deregulation contributes to pathologies including cancer. A challenging problem is to decipher how stochastic protein movements and interactions lead to formation of dynamic architecture such as integrin-dependent adhesive structures. In this review, we will describe recent advances made possible by super-resolution microscopies and single molecule tracking approaches that provided new understanding on the organization and the dynamics of integrins and intracellular regulators at the nanoscale in living cells.

  6. High-resolution recording of particle tracks with in-line holography in a large cryogenic bubble chamber

    CERN Document Server

    Harigel, G G

    2000-01-01

    Holography has been used successfully in combination with conventional optics for the first time in a large cryogenic bubble chamber, the 15-Foot Bubble Chamber at the Fermi National Accelerator Laboratory (FNAL), during a physics run in a high-energy neutrino beam. The innovative system combined the reference beam with the object beam, irradiating a conical volume of ~1.5 m/sup 3/. Bubble tracks from neutrino interactions with a width of ~120 mu m have been recorded with good contrast. The ratio of intensities of the object light to the reference light striking the film is called the beam branching ratio (BBR). We obtained in our experiment an exceedingly small minimum-observable ratio of BBR=(0.54/0.21)*10/sup -7/. The technology has the potential for a wide range of applications. This paper describes the various difficulties in achieving the success. It required the development of laser pulse stretching via enhanced closed loop control with slow Q-switching, to overcome excessive heating of the cryogenic l...

  7. Highly porous nanoberyllium for X-ray beam speckle suppression

    Energy Technology Data Exchange (ETDEWEB)

    Goikhman, Alexander, E-mail: agoikhman@ymail.com; Lyatun, Ivan; Ershov, Petr [Immanuel Kant Baltic Federal University, Nevskogo str. 14, Kaliningrad 236041 (Russian Federation); Snigireva, Irina [European Synchrotron Radiation Facility, BP 220, 38043 Grenoble (France); Wojda, Pawel [Immanuel Kant Baltic Federal University, Nevskogo str. 14, Kaliningrad 236041 (Russian Federation); Gdańsk University of Technology, 11/12 G. Narutowicza, Gdańsk 80-233 (Poland); Gorlevsky, Vladimir; Semenov, Alexander; Sheverdyaev, Maksim; Koletskiy, Viktor [A. A. Bochvar High-Technology Scientific Research Institute for Inorganic Materials, Rogova str. 5a, Moscow 123098 (Russian Federation); Snigirev, Anatoly [Immanuel Kant Baltic Federal University, Nevskogo str. 14, Kaliningrad 236041 (Russian Federation); European Synchrotron Radiation Facility, BP 220, 38043 Grenoble (France)

    2015-04-09

    A speckle suppression device containing highly porous nanoberyllium is proposed for manipulating the spatial coherence length and removing undesirable speckle structure during imaging experiments. This paper reports a special device called a ‘speckle suppressor’, which contains a highly porous nanoberyllium plate squeezed between two beryllium windows. The insertion of the speckle suppressor in an X-ray beam allows manipulation of the spatial coherence length, thus changing the effective source size and removing the undesirable speckle structure in X-ray imaging experiments almost without beam attenuation. The absorption of the nanoberyllium plate is below 1% for 1 mm thickness at 12 keV. The speckle suppressor was tested on the ID06 ESRF beamline with X-rays in the energy range from 9 to 15 keV. It was applied for the transformation of the phase–amplitude contrast to the pure amplitude contrast in full-field microscopy.

  8. A Novel Parallel Method for Speckle Masking Reconstruction Using the OpenMP

    Science.gov (United States)

    Li, Xuebao; Zheng, Yanfang

    2016-08-01

    High resolution reconstruction technology is developed to help enhance the spatial resolution of observational images for ground-based solar telescopes, such as speckle masking. Near real-time reconstruction performance is achieved on a high performance cluster using the Message Passing Interface (MPI). However, much time is spent in reconstructing solar subimages in such a speckle reconstruction. We design and implement a novel parallel method for speckle masking reconstruction of solar subimage on a shared memory machine using the OpenMP. Real tests are performed to verify the correctness of our codes. We present the details of several parallel reconstruction steps. The parallel implementation between various modules shows a great speed increase as compared to single thread serial implementation, and a speedup of about 2.5 is achieved in one subimage reconstruction. The timing result for reconstructing one subimage with 256×256 pixels shows a clear advantage with greater number of threads. This novel parallel method can be valuable in real-time reconstruction of solar images, especially after porting to a high performance cluster.

  9. Laser speckle micro-rheology for biomechanical evaluation of breast tumors (Conference Presentation)

    Science.gov (United States)

    Hajjarian Kashany, Zeinab; Nadkarni, Seemantini K.

    2016-03-01

    The stiffness of the extra cellular matrix (ECM) is recognized as a key regulator of cancer cell proliferation, migration and invasion. Therefore technologies that quantify ECM stiffness with micro-scale scale resolution will likely provide important insights into neoplastic progression. Laser Speckle Micro-Rheology (LSM) is a novel optical tool for measuring tissue viscoelastic properties with micro-scale resolution. In LSM, speckle images are collected through an objective lens by a high-speed camera. Spatio-temporal correlation analysis of speckle frames yields the intensity autocorrelation function, g2(t), for each pixel, and subsequently a 2D map of viscoelastic modulus, G*(ω) is reconstructed. Here, we investigate the utility of LSM for micro-mechanical evaluation of the ECM in human breast lesions. Specimens collected 18 women undergoing lumpectomy or mastectomy were evaluated with LSM. Because collagen is the key protein associated with ECM stiffness, G*(ω) maps obtained from LSM were compared with collagen content measured by second harmonic generation (SHG) microscopy. Regions of low G*(ω), identified by LSM, corresponded to low-intensity SHG signal and adipose tissue. Likewise, regions with high G*(ω) in LSM images matched high intensity SHG signal caused by desmoplastic collagen accumulation. Quantitative regression analysis demonstrated a strong, statistically significant correlation between G*(ω) and SHG signal intensity (R=0.66 pbreast cancer progression.

  10. Study Of Ho Lo-Speckle Interferometry

    Science.gov (United States)

    Chen, Jiabi

    1987-10-01

    Holo-speckle interferometry (HSI), as a 3-D displacement measuring method is studied in this paper. Three types of HSI are given. The average intensity distributions of its holographic and speckle interference fringes on the output planes are derived. The range of mea-surement and the problem of repositioning holograms for two-reference-beam HSI are disscussed. The results show that the upper limit of out-of-plane displacement is related to the parameters of the optical system and the in-plane displacement of specimen but the upper limit of in-plane displacement is determined by the paremeters only. The rigid body rotation of hologram in reconstruction process of two-reference-beam HSI influences the formation of interference fringes but the rigid body traslation does not have the influence.

  11. Temporal heterodyne shearing speckle pattern interferometry

    Science.gov (United States)

    Wang, Xu; Gao, Zhan; Qin, Jie; Zhang, Xiaoqiong; Yang, Shanwei

    2017-06-01

    Shearing speckle pattern interferometry is a full-field speckle interferometric technique used to determine surface displacement derivatives. In this paper, a new measurement system of real-time heterodyne shearography interferometry is presented. This system combined with heterodyne measurement, shearography interferometry and time domain signal processing technology can dynamically detect the out-of-plane displacement gradient. The principles and system arrangement are described. Using the Jones matrix, the mathematical expression of light intensity distribution passing through this system is deduced. A preliminary experiment was performed to demonstrate the performance of this new device, and simulations were conducted using the finite element method. Comparison of results shows that quantitative measurement of the displacement derivative has been achieved.

  12. Real-time implementation of coherent speckle suppression in B-scan images.

    Science.gov (United States)

    Bamber, J C; Phelps, J V

    1991-05-01

    Early experiences of new forms of adaptive filtering for ultrasound speckle reduction and parametric imaging, using off-line conventional digital processing, have been sufficiently encouraging to warrant examining the feasibility of implementing specific algorithms in real-time. A hardware two-dimensional real-time filter is described which consists of a hybrid digital/analogues system in which the video signal from any scanner is sampled to 256 points per line and passed sequentially through a series of shift registers, in order to derive a 5 x 5 window of values which surrounds the image point currently being processed. These 25 video signals are then used as inputs to an analogue processor, which provides the filtered output. The real-time processed images show clear evidence of speckle smoothing without blurring of tissue structural information but possess limited pixel resolution.

  13. Real time laser speckle imaging monitoring vascular targeted photodynamic therapy

    Science.gov (United States)

    Goldschmidt, Ruth; Vyacheslav, Kalchenko; Scherz, Avigdor

    2017-02-01

    Laser speckle imaging is a technique that has been developed to non-invasively monitor in vivo blood flow dynamics and vascular structure, at high spatial and temporal resolution. It can record the full-field spatio-temporal characteristics of microcirculation and has therefore, often been used to study the blood flow in tumors after photodynamic therapy (PDT). Yet, there is a paucity of reports on real-time laser speckle imaging (RTLSI) during PDT. Vascular-targeted photodynamic therapy (VTP) with WST11, a water-soluble bacteriochlorophyll derivative, achieves tumor ablation through rapid occlusion of the tumor vasculature followed by a cascade of events that actively kill the tumor cells. WST11-VTP has been already approved for treatment of early/intermediate prostate cancer at a certain drug dose, time and intensity of illumination. Application to other cancers may require different light dosage. However, incomplete vascular occlusion at lower light dose may result in cancer cell survival and tumor relapse while excessive light dose may lead to toxicity of nearby healthy tissues. Here we provide evidence for the feasibility of concomitant RTLSI of the blood flow dynamics in the tumor and surrounding normal tissues during and after WST11-VTP. Fast decrease in the blood flow is followed by partial mild reperfusion and a complete flow arrest within the tumor by the end of illumination. While the primary occlusion of the tumor feeding arteries and draining veins agrees with previous data published by our group, the late effects underscore the significance of light dose control to minimize normal tissue impairment. In conclusion- RTSLI application should allow to optimize VTP efficacy vs toxicity in both the preclinical and clinical arenas.

  14. Finding small displacements of recorded speckle patterns: revisited

    DEFF Research Database (Denmark)

    Hanson, Steen Grüner; Jakobsen, Michael Linde; Chakrabarti, Maumita

    2015-01-01

    An analytical expression for the bias effect in digital speckle correlation is derived based on a Gaussian approximation of the spatial pixel size and array extent. The evaluation is carried out having assumed an incident speckle field. The analysis is focused on speckle displacements in the order...... is introduced, which alleviates the need to know the expected shape of the crosscovariance between the original and the off-set recorded speckle pattern. This concept calls for correlating the crosscovariance with the auto covariance, which essentially carries information on the expected shape...

  15. Object wave reconstruction by speckle illumination and phase retrieval

    DEFF Research Database (Denmark)

    Almoro, Percival; Hanson, Steen Grüner

    2009-01-01

    An innovative setup for the speckle-based phase retrieval method is proposed. In the conventional setup, a plane wave illuminates the test object and the transmitted wavefront is incident on a diffuser aperture generating a speckle field. The sampled speckle intensities at axially displaced planes...... are input into a phase retrieval algorithm based on a wave propagation equation. In the new setup, the arrangement of the diffuser and the object is reversed. A plane wave incident on the diffuser generates a speckle field which, in turn, is used to illuminate the object. The transmitted wavefront...

  16. Extending temporal coherence in speckle interferometry

    Science.gov (United States)

    Crespo Contiñas, J. M.; Moreno de las Cuevas, V.; Gallas Torreira, M.; Calizaya Calizaya, M.

    2013-11-01

    Electronic Speckle Pattern Interferometry (ESPI) and Shearography (ESPSI) techniques have been used in the field of non-destructive testing for a long time, providing accuracy, and allowing whole field analysis of pure deformation (ESPI) or the gradient of deformation (ESPSI). One of the major weaknesses of this two techniques is linked to speckle de-correlation. When the deformation process produces a displacement greater than a certain proportion of the speckle size, there is a severe loss of coherence which limits the application of these techniques to processes with strong or fast deformations. In order to avoid this limitation, the use of a dynamically updated reference frame is tested in this work. First, in ESPI and ESPSI setups, a metacrylathe bar is used as specimen for testing procedures, and finally a human jaw bone will be used in an ESPSI setup. One basic and regular-shaped object, the bar, and a structurally 3D complex structure, the human jaw bone, with complex elastic properties are the samples to test.

  17. Early detection and treatment of Speckled leukoplakia

    Directory of Open Access Journals (Sweden)

    Selviana Tampoma

    2016-12-01

    Full Text Available Background: Leukoplakia is one of potentially malignant disorders that can be found on oral mucosa. Speckled leukoplakia is a rare type of leukoplakia with a very high risk of premalignant growth. Approximately 3 % of worldwide population has suffered from leukoplakia, 5-25% of which tend to be malignant leukoplakia. Purpose: This case report was aimed to discuss about early detection of speckled leukoplakia as one of potentially malignant disorders. Case: A 62 year old male patient came with chief complaint of bald and painful tongue since one month ago. The patient has a history of allergic reaction, hypertension, uric acid, and hepatitis B. He had been a heavy smoker since young until 10 years ago. Intra oral examination showed a firm, rough, non scrapable white plaque lesion with a size of 1 x 1.5 cm, surrounded by painful erosion with diffuse boundary. Case Management: Based on cytology examination, the patient was reffered to oncologist to get an excisional biopsy. Next, the patient succesfully underwent the excisional biopsy and came for control. The results showed the healing process of the lesion with a minimal complaint of bald tongue, especially when eating spicy or hot meal. To improve healing process, the patient then was given an antibacterial mouth rinse containing zinc and mulvitamin. Conclusion: Speckled leukoplakia could show high malignant transformation rate, therefore, early detection and treatment are necessary.

  18. Alternative protocols on dynamic speckle laser analysis

    Science.gov (United States)

    Cardoso, Rafael R.; Braga, Roberto A.; Rabal, Hector J.

    2012-10-01

    Biospeckle or dynamic laser speckle is a phenomenon developed when a dynamic process occurs in a material under laser illumination. This phenomenon contains considerable information related to both biological and non-biological activity of the material under study. As a non-invasive, non-destructive and low cost technique, biospeckle laser (BSL) has been an outstanding tool for monitoring biological properties. Thus, its application in optical instrumentation has grown over the years, especially in the areas of biology, medicine and agriculture. High sensitivity of biospeckle laser (BSL) technique and variability of biological material combined with the large number of variables involved in speckle pattern formation have brought great challenges to the search for safer, more robust analysis techniques. Therefore, this study aimed to develop and refine methodologies for the BSL analysis and tested alternative protocols for the prime analysis. Particularly, we present a protocol to obtain requirements before the main analysis, in an attempt to eliminate image quality based on subjectivism or research experience. This protocol was based on the creation of requirements to achieve the best speckle patterns such as evaluating the saturation, the homogeneity and the contrast of the grains. The alternative protocol offered a testing approach before the main experiment to increase the certainty to get image and data in an accepted quality, avoiding the loose of time and samples in analysis of a row of a questionable data. The tests were performed in well-known BSL data and presented as a feasible step before the main experiments.

  19. THE DUAL-TRACK APPROACH OF THE PRC TO THE RESOLUTION OF DISPUTES IN THE SOUTH CHINA SEA

    Directory of Open Access Journals (Sweden)

    Т И Понька

    2017-12-01

    Full Text Available The Asia-Pacific region is becoming one of the centers of global economic and political development. Countries of the region actively develop their economy, implement democratic reforms, and are also interested in peace and security in the region. A serious destabilizing factor in the Asia-Pacific region is territorial disputes between China and a number of countries in the region. China is taking the lead in the region and resolutely defends its interests, including territorial ones. The growing economic and military strength of China bothers other countries of Asia-Pacific region. Japan, Vietnam, South Korea, Indonesia also claim regional leadership. They also demonstrate determination in their territorial claims. Confrontation with China encourages the countries of the region to seek political and military support from the US, that could lead to the aggravation of the situation in the region in future. Meanwhile, China is also interested in good relations with neighbors, that’s why it changes approaches of solving its territorial issues. The objective of the research is to define China’s approach to territorial disputes in Asia-Pacific region. For this purpose, the authors set some tasks: first, to point out the main territorial disputes between China and Asia-Pacific countries, second, to consider how the problem of territorial disputes in Asia-Pacific region first appeared and developed, and how the Chinese government reacted to it, and finally, to analyze the role of international organizations, such as the UN and ASEAN in settling disputes in Asia-Pacific region. Summarizing the results of their research, the authors make the important conclusion that China’s stance on disputed territories remains unchanged, and at the same time, Chinese government seeks to solve the existing territorial problems peacefully, without using military force.

  20. Non-invasive high-resolution tracking of human neuronal pathways: diffusion tensor imaging at 7T with 1.2 mm isotropic voxel size

    Science.gov (United States)

    Lützkendorf, Ralf; Hertel, Frank; Heidemann, Robin; Thiel, Andreas; Luchtmann, Michael; Plaumann, Markus; Stadler, Jörg; Baecke, Sebastian; Bernarding, Johannes

    2013-03-01

    Diffusion tensor imaging (DTI) allows characterizing and exploiting diffusion anisotropy effects, thereby providing important details about tissue microstructure. A major application in neuroimaging is the so-called fiber tracking where neuronal connections between brain regions are determined non-invasively by DTI. Combining these neural pathways within the human brain with the localization of activated brain areas provided by functional MRI offers important information about functional connectivity of brain regions. However, DTI suffers from severe signal reduction due to the diffusion-weighting. Ultra-high field (UHF) magnetic resonance imaging (MRI) should therefore be advantageous to increase the intrinsic signal-to-noise ratio (SNR). This in turn enables to acquire high quality data with increased resolution, which is beneficial for tracking more complex fiber structures. However, UHF MRI imposes some difficulties mainly due to the larger B1 inhomogeneity compared to 3T MRI. We therefore optimized the parameters to perform DTI at a 7 Tesla whole body MR scanner equipped with a high performance gradient system and a 32-channel head receive coil. A Stesjkal Tanner spin-echo EPI sequence was used, to acquire 110 slices with an isotropic voxel-size of 1.2 mm covering the whole brain. 60 diffusion directions were scanned which allows calculating the principal direction components of the diffusion vector in each voxel. The results prove that DTI can be performed with high quality at UHF and that it is possible to explore the SNT benefit of the higher field strength. Combining UHF fMRI data with UHF DTI results will therefore be a major step towards better neuroimaging methods.

  1. Measuring tissue dispersion using optical coherence tomography speckle

    Science.gov (United States)

    Photiou, Christos; Bousi, Evgenia; Zouvani, Ioanna; Pitris, Costas

    2017-07-01

    Dispersion mismatch between the two arms of an Optical Coherence Tomography (OCT) interferometer causes degradation of the image resolution. However, dispersion in tissue is specific to the chemical constituents of the cells and can therefore carry diagnostically useful information. Unfortunately, dispersion measurement techniques, presented so far in the literature, require the presence of strong distinct reflections in the OCT image which are rarely present when imaging tissues in vivo. The novel method presented here relies on the image speckle to calculate the PSF degradation and is therefore applicable to any tissue and can be implemented in vivo and in situ. The resolution degradation is estimated using a Wiener-type deconvolution and was verified ex vivo resulting in Group Velocity Dispersion (GVD) values comparable to the standard techniques. This technique has also been applied to normal and malignant samples of human colon to evaluate its applicability for cancer diagnosis. Using the statistics of the GVD estimate, the tissue classification resulted in 93% sensitivity and 100% specificity (96% correct classification rate). The success of these preliminary results indicates the potential of the proposed method which should be further.

  2. Numerical correction of aberrations via phase retrieval with speckle illumination

    DEFF Research Database (Denmark)

    Almoro, Percival; Gundu, Phanindra Narayan; Hanson, Steen Grüner

    2009-01-01

    What we believe to be a novel technique for wavefront aberration measurement using speckle patterns is presented. The aberration correction is done numerically. A tilted lens is illuminated with a partially developed speckle field, and the transmitted light intensity is sampled at axially displaced...

  3. Compound speckles and their statistical and dynamical properties

    DEFF Research Database (Denmark)

    Hanson, Steen Grüner; Jakobsen, Michael Linde; Skov Hansen, Rene

    2008-01-01

    Two issues will be treated in this presentation, both focusing on gaining a deeper understanding of dynamic speckles, aiming at the use for probing dynamical properties of scattering structures. The first issue to be addressed is the dynamics of speckles arising from illuminating a solid surface...

  4. Speckle filtering in satellite SAR change detection imagery

    NARCIS (Netherlands)

    Dekker, R.J.

    1998-01-01

    Repeat-pass Synthetic Aperture Radar (SAR) imagery is useful for change detection. A disadvantage of SAR is the system-inherent speckle noise. This can be reduced by filtering. Various filter types and methods are described in the literature, but not one fits the speckle noise in change detection

  5. Integration of speckle de-noising and image segmentation using ...

    Indian Academy of Sciences (India)

    flood assessment models. In this paper, we propose remote sensing based flood assessment using Synthetic. Aperture Radar (SAR) image because of its imperviousness to unfavourable weather conditions. However, they suffer from the speckle noise. Hence, the processing of SAR image is applied in two stages: speckle.

  6. Using of methods of speckle optics for Chlamydia trachomatis typing

    Science.gov (United States)

    Ulyanov, Sergey S.; Zaytsev, Sergey S.; Ulianova, Onega V.; Saltykov, Yury V.; Feodorova, Valentina A.

    2017-03-01

    Specific method of transformation of nucleotide of gene into speckle pattern is suggested. Reference speckle pattern of omp1 gene of typical wild strains of Chlamydia trachomatis of genovars D, E, F, G, J and K and Chlamydia psittaci as well is generated. Perspectives of proposed technique in the gene identification and detection of natural genetic mutations as single nucleotide polymorphism (SNP) are demonstrated.

  7. Polarization speckles and generalized Stokes vector wave: a review [invited

    DEFF Research Database (Denmark)

    Takeda, Mitsuo; Wang, Wei; Hanson, Steen Grüner

    2010-01-01

    We review some of the statistical properties of polarization-related speckle phenomena, with an introduction of a less known concept of polarization speckles and their spatial degree of polarization. As a useful means to characterize twopoint vector field correlations, we review the generalized...

  8. Speckle Contrast Reduction with a Visible VCSEL Projector

    OpenAIRE

    Sabuncu,Metin; Yilmazlar,İsmail

    2016-01-01

    Speckle contrast reduction in a laser projector that has a VCSEL emitting in the visible spectrum as its light source can be achieved electronically. Employing a drive circuit enables exciting independent longitudinal modes of the VCSEL. By modulating the VCSEL current continuously with a triangular wave rather than with pulses, the speckle noise could be reduced.

  9. Tracking and evolution of irrigation triggered active landslides by multi-source high resolution DEM: The Jiaojiacun landslide group of Heifangtai (Northwest of China)

    Science.gov (United States)

    Zeng, Runqiang; Meng, Xingmin; Wang, Siyuan; Chen, Guan; Lee, Yajun; Zhang, Yi

    2014-05-01

    The construction of three large hydropower stations, i.e. Liujia, Yanguo and Bapan, resulted in the immigration of the impacted people to Heifangtai from 1960s. To support the living and farming of the immigrated people, a large amount of water has been pumped from the Yellow River to Heifangtai, which has changed the former underground water budget and led to 111 landslides from 1968 in this area. To reveal the deformation process of landslides in Heifangtai, a quantitative deformation analysis model of landslide based on multi-source DEM data is established using four periods of topographic maps obtained in 1970, 2001, 2010 and 2013 respectively, including two 1:10000 topographic maps and two 1:1000 data acquired from 3D Laser Scanner. The whole study area was divided into two sections based on the two distinct kinds of landslide patterns. The selected morphometric parameters, residual topographic surface and surface roughness, extracted from three typical landslides, and the statistical analysis (Box-plot diagrams) of the temporal variations of these parameters, allowed the reconstruction and tracking of these landslides. We monitored the changing of landslide boundaries, average vertical and horizontal displacement rates and zones of uplift and subsidence. The volumes of removed and/or accumulated material were estimated as well. We can then demonstrate the kinematics of landslides based on information from high-resolution DEM, and the changing table of underground water, ring-shear test and soil-water characteristic curve referenced from other researchers. The results provide a new insight on the use of multi-source high resolution DEM in the monitoring of irrigation-triggered landslides.

  10. Laser speckle imaging of rat retinal blood flow with hybrid temporal and spatial analysis method

    Science.gov (United States)

    Cheng, Haiying; Yan, Yumei; Duong, Timothy Q.

    2009-02-01

    Noninvasive monitoring of blood flow in retinal circulation will reveal the progression and treatment of ocular disorders, such as diabetic retinopathy, age-related macular degeneration and glaucoma. A non-invasive and direct BF measurement technique with high spatial-temporal resolution is needed for retinal imaging. Laser speckle imaging (LSI) is such a method. Currently, there are two analysis methods for LSI: spatial statistics LSI (SS-LSI) and temporal statistical LSI (TS-LSI). Comparing these two analysis methods, SS-LSI has higher signal to noise ratio (SNR) and TSLSI is less susceptible to artifacts from stationary speckle. We proposed a hybrid temporal and spatial analysis method (HTS-LSI) to measure the retinal blood flow. Gas challenge experiment was performed and images were analyzed by HTS-LSI. Results showed that HTS-LSI can not only remove the stationary speckle but also increase the SNR. Under 100% O2, retinal BF decreased by 20-30%. This was consistent with the results observed with laser Doppler technique. As retinal blood flow is a critical physiological parameter and its perturbation has been implicated in the early stages of many retinal diseases, HTS-LSI will be an efficient method in early detection of retina diseases.

  11. Speckle-based at-wavelength metrology of x-ray optics at Diamond Light Source

    Science.gov (United States)

    Wang, Hongchang; Zhou, Tunhe; Kashyap, Yogesh; Sawhney, Kawal

    2017-08-01

    To achieve high resolution and sensitivity on the nanometer scale, further development of X-ray optics is required. Although ex-situ metrology provides valuable information about X-ray optics, the ultimate performance of X-ray optics is critically dependent on the exact nature of the working conditions. Therefore, it is equally important to perform in-situ metrology at the optics' operating wavelength (`at-wavelength' metrology) to optimize the performance of X-ray optics and correct and minimize the collective distortions of the upstream beamline optics, e.g. monochromator, windows, etc. Speckle-based technique has been implemented and further improved at Diamond Light Source. We have demonstrated that the angular sensitivity for measuring the slope error of an optical surface can reach an accuracy of two nanoradians. The recent development of the speckle-based at-wavelength metrology techniques will be presented. Representative examples of the applications of the speckle-based technique will also be given - including optimization of X-ray mirrors and characterization of compound refraction lenses. Such a high-precision metrology technique will be extremely beneficial for the manufacture and in-situ alignment/optimization of X-ray mirrors for next-generation synchrotron beamlines.

  12. Improvement of the sensitivity in velocity sensing using dynamic speckles

    Science.gov (United States)

    Yokoi, Naomichi; Aizu, Yoshihisa

    2017-12-01

    Dynamic speckle patterns can be used for imaging of relative velocity of moving objects in fields of biomedical and mechanical measurements. In spite of the widespread use of this method, the effect of speckle size on velocity sensing has not fully been estimated so far. In addition, effects of speckle contrast and random noises on the sensitivity of velocity sensing have not been investigated yet. In the present study, we estimated condition of image processing of speckle patterns for reducing effects of random noises with relation to linearity and sensitivity in velocity sensing. We further introduced binarization of the speckle pattern to improve the sensitivity in velocity sensing. Experiments were conducted for sample models using a diffusive plate and fluid flows to confirm the feasibility of the proposed method.

  13. Alternating minimization algorithm for speckle reduction with a shifting technique.

    Science.gov (United States)

    Woo, Hyenkyun; Yun, Sangwoon

    2012-04-01

    Speckles (multiplicative noise) in synthetic aperture radar (SAR) make it difficult to interpret the observed image. Due to the edge-preserving feature of total variation (TV), variational models with TV regularization have attracted much interest in reducing speckles. Algorithms based on the augmented Lagrangian function have been proposed to efficiently solve speckle-reduction variational models with TV regularization. However, these algorithms require inner iterations or inverses involving the Laplacian operator at each iteration. In this paper, we adapt Tseng's alternating minimization algorithm with a shifting technique to efficiently remove the speckle without any inner iterations or inverses involving the Laplacian operator. The proposed method is very simple and highly parallelizable; therefore, it is very efficient to despeckle huge-size SAR images. Numerical results show that our proposed method outperforms the state-of-the-art algorithms for speckle-reduction variational models with a TV regularizer in terms of central-processing-unit time.

  14. Escherichia coli activity characterization using a laser dynamic speckle technique

    CERN Document Server

    Ramírez-Miquet, Evelio E; Contreras-Alarcón, Orestes R

    2012-01-01

    The results of applying a laser dynamic speckle technique to characterize bacterial activity are presented. The speckle activity was detected in two-compartment Petri dishes. One compartment was inoculated and the other one was left as a control blank. The speckled images were processed by the recently reported temporal difference method. Three inoculums of 0.3, 0.5, and 0.7 McFarland units of cell concentration were tested; each inoculum was tested twice for a total of six experiments. The dependences on time of the mean activity, the standard deviation of activity and other descriptors of the speckle pattern evolution were calculated for both the inoculated compartment and the blank. In conclusion the proposed dynamic speckle technique allows characterizing the activity of Escherichia coli bacteria in solid medium.

  15. X-ray speckle measurements of concentrated nanoemulsions under shear

    Science.gov (United States)

    Abidib, Samy; Rogers, Michael; Leheny, Robert; Chen, Kui; Mason, Thomas; Harden, James

    We present in situ X-ray Photon Correlation Spectroscopy (XPCS) measurements of a set of concentrated nanoemulsions subjected to oscillatory shear. The nanoemulsion set contained samples with varying packing fractions of oil droplets (r 20nm) above the jamming transition. In order to study their elasticity, yielding, and flow at various shear amplitudes, we employed stroboscopic coherent X-ray scattering measurements triggered at the maximums of the shear cycle. The degree of correlation between speckle in images taken a full period apart is a direct measurement of particle rearrangements during cycling. A comparison of such XPCS ``echo'' measurements with rheological measurements shows an onset of irreversible particle motion at shear strains below the crossover of the storage and loss moduli, which is typically used to indicate the transition to viscoplastic flow. Moreover, the XPCS echo measurements indicate that particle irreversibility increases rapidly with shear amplitude, in contrast to the comparably smooth transition to yielding shown in bulk rheology measurements. However, the macroscopic yield strain observed in rheology and the microscopic yield strain identified from XPCS, which were strong functions of droplet packing fraction, tracked each other closely.

  16. Electronic speckle pattern interferometrie through shearography

    Science.gov (United States)

    Schulz, Bernd

    1994-09-01

    Measurement systems based on image processing are used more and more in quality control. With aid of the interference ability of laserlight it is possible to gain the lost third dimension of 'normal' images in form of a phase relation. At the Lehrstuhl fur Feingeratebau der TU Munchen an electronic-speckle-pattern-interferometry (ESPI)-camera was constructed and continuously developed. The new arrangement enables to evaluate vibrations and deformations by ESPI and by Shearing Interferometry. Enjoyable are also the small dimensions of the camera.

  17. Laser speckle analysis of retinal vascular dynamics

    DEFF Research Database (Denmark)

    Neganova, Anastasiia Y.; Postnov, Dmitry D.; Jacobsen, Jens Christian B.

    2016-01-01

    Studies of vascular responses are usually performed on isolated vessels or on single vessels in vivo. This allows for precise measurements of diameter or blood flow. However, dynamical responses of the whole microvascular network are difficult to access experimentally. We suggest to use full......-field laser speckle imaging to evaluate vascular responses of the retinal network. Image segmentation and vessel recognition algorithms together with response mapping allow us to analyze diameter changes and blood flow responses in the intact retinal network upon systemic administration of the vasoconstrictor...

  18. Laser speckle imaging in the spatial frequency domain.

    Science.gov (United States)

    Mazhar, Amaan; Cuccia, David J; Rice, Tyler B; Carp, Stefan A; Durkin, Anthony J; Boas, David A; Choi, Bernard; Tromberg, Bruce J

    2011-06-01

    Laser Speckle Imaging (LSI) images interference patterns produced by coherent addition of scattered laser light to map subsurface tissue perfusion. However, the effect of longer path length photons is typically unknown and poses a limitation towards absolute quantification. In this work, LSI is integrated with spatial frequency domain imaging (SFDI) to suppress multiple scattering and absorption effects. First, depth sensitive speckle contrast is shown in phantoms by separating a deep source (4 mm) from a shallow source (2 mm) of speckle contrast by using a high spatial frequency of illumination (0.24 mm(-1)). We develop an SFD adapted correlation diffusion model and show that with high frequency (0.24 mm(-1)) illumination, doubling of absorption contrast results in only a 1% change in speckle contrast versus 25% change using a planar unmodulated (0 mm(-1)) illumination. Similar absorption change is mimicked in vivo imaging a finger occlusion and the relative speckle contrast change from baseline is 10% at 0.26 mm(-1) versus 60% at 0 mm(-1) during a finger occlusion. These results underscore the importance of path length and optical properties in determining speckle contrast. They provide an integrated approach for simultaneous mapping of blood flow (speckle contrast) and oxygenation (optical properties) which can be used to inform tissue metabolism.

  19. Speckle reduction in THz imaging systems with multiple phase patterns

    Science.gov (United States)

    Jaeger, Irina; Stiens, Johan; Koers, Gaetan; Poesen, Gert; Vounckx, Roger

    2006-04-01

    THz technology makes possible imaging of phenomena, inaccessible to both visible and infrared radiation, but the imaging is still in its early stages of development. This paper draws attention to the aspects of speckle reduction to improve the image quality. Because all existing THz sources are coherent - speckle is an ultimate limiting factor of the free-space imaging techniques. Speckle arises when coherent light scattered from a rough surface is detected by an intensity detector with a finite aperture, hiding the image information. This problem is of special importance for THz imaging, because surface roughness is closer to the object dimension as in optical imaging. The reduction of speckle is highly desirable and we propose here a Hadamard matrix solution. Hadamard diffuser for mm-wave frequency range have been designed, built and tested. We report 50% speckle reduction measurements using a free-space vector network analyzer over the full W-band (75-110 GHz). The advantage of the mm-wave Hadamard technology over optical: the diffuser doesn't have to be moved (vibrated) any more to accomplish the technology of speckle reduction. Temporal optical effect is substituted here by spatial quasi-optical: Hadamard coding in each scan pixel. Second method delivers realistic system parameters for the speckle reduction with polychromatic light for aviation security.

  20. Lacunarity study of speckle patterns produced by rough surfaces

    Science.gov (United States)

    Dias, M. R. B.; Dornelas, D.; Balthazar, W. F.; Huguenin, J. A. O.; da Silva, L.

    2017-11-01

    In this work we report on the study of Lacunarity of digital speckle patterns generated by rough surfaces. The study of Lacunarity of speckle patterns was performed on both static and moving rough surfaces. The results show that the Lacunarity is sensitive to the surface roughness, which suggests that it can be used to perform indirect measurement of surface roughness as well as to monitor defects, or variations of roughness, of metallic moving surfaces. Our results show the robustness of this statistical tool applied to speckle pattern in order to study surface roughness.

  1. A Comparison of Speckle Reduction Techniques in Medical Ultrasound Imaging

    Directory of Open Access Journals (Sweden)

    Cristina STOLOJESCU-CRISAN

    2015-06-01

    Full Text Available Speckle noise is a multiplicative noise that degrades the visual evaluation in ultrasound imaging. In addition, it limits the efficient application of intelligent image processing algorithms, such as segmentation techniques. Thus, speckle noise reduction is considered an essential pre-processing step. The objective of this paper is to carry out a comparative evaluation of speckle filtering techniques, based on two image quality evaluation metrics, the Peak Signal to Noise Ratio (PSNR, and the Structural SIMilarity (SSIM index, and visual evaluation.

  2. Doppler tracking

    Science.gov (United States)

    Thomas, Christopher Jacob

    This study addresses the development of a methodology using the Doppler Effect for high-resolution, short-range tracking of small projectiles and vehicles. Minimal impact on the design of the moving object is achieved by incorporating only a transmitter in it and using ground stations for all other components. This is particularly useful for tracking objects such as sports balls that have configurations and materials that are not conducive to housing onboard instrumentation. The methodology developed here uses four or more receivers to monitor a constant frequency signal emitted by the object. Efficient and accurate schemes for filtering the raw signals, determining the instantaneous frequencies, time synching the frequencies from each receiver, smoothing the synced frequencies, determining the relative velocity and radius of the object and solving the nonlinear system of equations for object position in three dimensions as a function of time are developed and described here.

  3. Prosthetic clone and natural human tooth comparison by speckle interferometry

    Science.gov (United States)

    Slangen, Pierre; Corn, Stephane; Fages, Michel; Raynal, Jacques; Cuisinier, Frederic J. G.

    2010-09-01

    New trends in dental prosthodontic interventions tend to preserve the maximum of "body" structure. With the evolution of CAD-CAM techniques, it is now possible to measure "in mouth" the remaining dental tissues. The prosthetic crown is then designed using this shape on which it will be glued on, and also by taking into account the contact surface of the opposite jaw tooth. Several theories discuss on the glue thickness and formulation, but also on the way to evolve to a more biocompatible crown and also new biomechanical concepts. In order to validate these new concepts and materials, and to study the mechanical properties and mechanical integrity of the prosthesis, high resolution optical measurements of the deformations of the glue and the crown are needed. Samples are two intact premolars extracted for orthodontics reasons. The reference sample has no modifications on the tooth while the second sample tooth is shaped to receive a feldspathic ceramic monoblock crown which will be glued. This crown was manufactured with a chairside CAD-CAM system from an intra-oral optical print. The software allows to realize a nearly perfect clone of the reference sample. The necessary space for the glue is also entered with ideal values. This duplication process yields to obtain two samples with identical anatomy for further processing. The glue joint thickness can also be modified if required. The purpose is to compare the behaviour of a natural tooth and its prosthetic clone manufactured with "biomechanical" concepts. Vertical cut samples have been used to deal with planar object observation, and also to look "inside" the tooth. We have developed a complete apparatus enabling the study of the compressive mechanical behaviour of the concerned tooth by speckle interferometry. Because in plane displacements are of great interest for orthodontic measurements1, an optical fiber in-plane sensitive interferometer has been designed. The fibers are wrapped around piezoelectric

  4. Large scale tracking algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, Ross L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Love, Joshua Alan [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Melgaard, David Kennett [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Karelitz, David B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Pitts, Todd Alan [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Zollweg, Joshua David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Anderson, Dylan Z. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Nandy, Prabal [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Whitlow, Gary L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bender, Daniel A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Byrne, Raymond Harry [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-01-01

    Low signal-to-noise data processing algorithms for improved detection, tracking, discrimination and situational threat assessment are a key research challenge. As sensor technologies progress, the number of pixels will increase signi cantly. This will result in increased resolution, which could improve object discrimination, but unfortunately, will also result in a significant increase in the number of potential targets to track. Many tracking techniques, like multi-hypothesis trackers, suffer from a combinatorial explosion as the number of potential targets increase. As the resolution increases, the phenomenology applied towards detection algorithms also changes. For low resolution sensors, "blob" tracking is the norm. For higher resolution data, additional information may be employed in the detection and classfication steps. The most challenging scenarios are those where the targets cannot be fully resolved, yet must be tracked and distinguished for neighboring closely spaced objects. Tracking vehicles in an urban environment is an example of such a challenging scenario. This report evaluates several potential tracking algorithms for large-scale tracking in an urban environment.

  5. Ice Velocity Mapping Using TOPS SAR Data and Offset Tracking

    DEFF Research Database (Denmark)

    Dall, Jørgen; Kusk, Anders; Nielsen, Ulrik

    2015-01-01

    Feature tracking and speckle tracking, are robust techniques to measure the velocity of glaciers and ice sheets. Displacement maps based on TOPS data may have small gaps if the bursts are not handled properly. Ice moving from one burst to a consecutive burst between two observations is not observ...... of Sentinel-1 product, as consecutive bursts overlap in the SLC product but not in the GRD product. An analysis of Sentinel-1 data from Greenland confirms the results expected from theory....

  6. Laser speckle velocimetry for robot manufacturing

    Science.gov (United States)

    Charrett, Thomas O. H.; Bandari, Yashwanth K.; Michel, Florent; Ding, Jialuo; Williams, Stewart W.; Tatam, Ralph P.

    2017-06-01

    A non-contact speckle correlation sensor for the measurement of robotic tool speed is presented for use in robotic manufacturing and is capable of measuring the in-plane relative velocities between a robot end-effector and the workpiece or other surface. The sensor performance was assessed in the laboratory with the sensor accuracies found to be better than 0:01 mm/s over a 70 mm/s velocity range. Finally an example of the sensors application to robotic manufacturing is presented where the sensor was applied to tool speed measurement for path planning in the wire and arc additive manufacturing process using a KUKA KR150 L110/2 industrial robot.

  7. Simple educational tool for digital speckle shearography

    Science.gov (United States)

    Schirripa Spagnolo, Giuseppe; Martocchia, Andrea; Papalillo, Donato; Cozzella, Lorenzo

    2012-07-01

    In this study, an educational tool has been prepared for obtaining short-term and more economic training on digital speckle shearography (DSS). Shearography non-destructive testing (NDT) has gained wide acceptance over the last decade, providing a number of important and exciting inspection solutions in aerospace, electronics and medical device manufacturing. For exploring these motivations, it is important to develop didactic tools to understand the potential of digital shearography through training and didactic courses in the field of NDT. In this paper we describe a simple tool for making one familiar with the potential of DSS in the area of education and training. The system is realized with a simple and economic optical setup and a virtual instrument based on the LabVIEW™ and DAQ.

  8. Speckle Filtering of Polarimetric SAR Interferometry Data

    Science.gov (United States)

    Lee, J.-S.; Cloude, S.; Grunes, M. R.; Papathanassiou, K.

    2003-04-01

    Recently, polarimetric SAR interferometry has generated much interest for forest applications. Tree heights and ground topography can be extracted based on interferometric coherence using a random volume over ground coherent mixture model. The coherence estimation is of paramount importance for the accuracy of tree height estimation. The coherence (or correlation coefficient) is a statistical average of neighboring pixels of similar scattering characteristics. The commonly used algorithm is the boxcar filter, which has the deficiency of indiscriminate averaging of neighboring pixels. The result is that coherence values are lower than they should be. In this paper, we propose a new algorithm to improve the accuracy in the coherence estimation based on speckle filtering of the 6x6 polarimetric interferometry matrix. Simulated images are used to verify the effectiveness of this algorithm. L-Band DLR ESAR data are used to demonstrate the improved accuracy in coherence and in tree height estimation.

  9. Papular Speckled Lentiginous Nevus: Case Report

    Directory of Open Access Journals (Sweden)

    Berna Aksoy

    2010-06-01

    Full Text Available Cutaneous mosaicism may be encountered with different patterns. Type II mosaicism - checkerboard pattern is characterized by flag-like areas with a sharp midline separation. The speckled lentiginous nevus (BLN and Becker nevus are clinical examples of this pattern. A 38-year-old woman attended the outpatient clinic with a complaint of spots located over the left upper part of her body. These spots had been present from about eight years of age and showed a progressive course. Her mother also had a history of similar lesions. On dermatologic examination a diffuse, flag-like patch including brown macules was present over the left upper anterior trunk and left upper extremity. In this case report a case having BLN localized in type II mozaisizm- checkerboard pattern, which has not been reported previously in the Turkish literature, was presented.

  10. High resolution telescope including an array of elemental telescopes aligned along a common axis and supported on a space frame with a pivot at its geometric center

    Science.gov (United States)

    Norbert, Massie A.; Yale, Oster

    1992-01-01

    A large effective-aperture, low-cost optical telescope with diffraction-limited resolution enables ground-based observation of near-earth space objects. The telescope has a non-redundant, thinned-aperture array in a center-mount, single-structure space frame. It employes speckle interferometric imaging to achieve diffraction-limited resolution. The signal-to-noise ratio problem is mitigated by moving the wavelength of operation to the near-IR, and the image is sensed by a Silicon CCD. The steerable, single-structure array presents a constant pupil. The center-mount, radar-like mount enables low-earth orbit space objects to be tracked as well as increases stiffness of the space frame. In the preferred embodiment, the array has elemental telescopes with subaperture of 2.1 m in a circle-of-nine configuration. The telescope array has an effective aperture of 12 m which provides a diffraction-limited resolution of 0.02 arc seconds. Pathlength matching of the telescope array is maintained by a electro-optical system employing laser metrology. Speckle imaging relaxes pathlength matching tolerance by one order of magnitude as compared to phased arrays. Many features of the telescope contribute to substantial reduction in costs. These include eliminating the conventional protective dome and reducing on-site construction activities. The cost of the telescope scales with the first power of the aperture rather than its third power as in conventional telescopes.

  11. Evaluating platelet aggregation dynamics from laser speckle fluctuations.

    Science.gov (United States)

    Hajjarian, Zeinab; Tshikudi, Diane M; Nadkarni, Seemantini K

    2017-07-01

    Platelets are key to maintaining hemostasis and impaired platelet aggregation could lead to hemorrhage or thrombosis. We report a new approach that exploits laser speckle intensity fluctuations, emanated from a drop of platelet-rich-plasma (PRP), to profile aggregation. Speckle fluctuation rate is quantified by the speckle intensity autocorrelation, g2(t), from which the aggregate size is deduced. We first apply this approach to evaluate polystyrene bead aggregation, triggered by salt. Next, we assess dose-dependent platelet aggregation and inhibition in human PRP spiked with adenosine diphosphate and clopidogrel. Additional spatio-temporal speckle analyses yield 2-dimensional maps of particle displacements to visualize platelet aggregate foci within minutes and quantify aggregation dynamics. These findings demonstrate the unique opportunity for assessing platelet health within minutes for diagnosing bleeding disorders and monitoring anti-platelet therapies.

  12. Assessing blood coagulation status with laser speckle rheology

    Science.gov (United States)

    Tripathi, Markandey M.; Hajjarian, Zeinab; Van Cott, Elizabeth M.; Nadkarni, Seemantini K.

    2014-01-01

    We have developed and investigated a novel optical approach, Laser Speckle Rheology (LSR), to evaluate a patient’s coagulation status by measuring the viscoelastic properties of blood during coagulation. In LSR, a blood sample is illuminated with laser light and temporal speckle intensity fluctuations are measured using a high-speed CMOS camera. During blood coagulation, changes in the viscoelastic properties of the clot restrict Brownian displacements of light scattering centers within the sample, altering the rate of speckle intensity fluctuations. As a result, blood coagulation status can be measured by relating the time scale of speckle intensity fluctuations with clinically relevant coagulation metrics including clotting time and fibrinogen content. Our results report a close correlation between coagulation metrics measured using LSR and conventional coagulation results of activated partial thromboplastin time, prothrombin time and functional fibrinogen levels, creating the unique opportunity to evaluate a patient’s coagulation status in real-time at the point of care. PMID:24688816

  13. Assessment of Fevicol (adhesive Drying Process through Dynamic Speckle Techniques

    Directory of Open Access Journals (Sweden)

    Mohammad Z. Ansari

    2015-04-01

    Full Text Available Dynamic laser speckle (or biospeckle analysis is a useful measurement tool to analyze micro-motion on a sample surface via temporal statistics based on a sequence of speckle images. The aim of this work was to evaluate the use of dynamic speckles as an alternative tool to monitoring Fevicol drying process. Experimental demonstration of intensity-based algorithm to monitor Fevicol drying process is reported. The experiment was explored with the technique called Inertia Moment of co-occurrence matrix. The results allowed verifying the drying process and it was possible to observe different activity stages during the drying process. Statistical Tukey test at 5% significance level allowed differentiating different stages of drying. In conclusion, speckle activity, measured by the Inertia Moment, can be used to monitor drying processes of the Fevicol.

  14. Speckle noise suppression method in holographic display using time multiplexing

    Science.gov (United States)

    Liu, Su-Juan; Wang, Di; Li, Song-Jie; Wang, Qiong-Hua

    2017-06-01

    We propose a method to suppress the speckle noise in holographic display using time multiplexing. The diffractive optical elements (DOEs) and the subcomputer-generated holograms (sub-CGHs) are generated, respectively. The final image is reconstructed using time multiplexing of the subimages and the final subimages. Meanwhile, the speckle noise of the final image is suppressed by reducing the coherence of the reconstructed light and separating the adjacent image points in space. Compared with the pixel separation method, the experiments demonstrate that the proposed method suppresses the speckle noise effectively with less calculation burden and lower demand for frame rate of the spatial light modulator. In addition, with increases of the DOEs and the sub-CGHs, the speckle noise is further suppressed.

  15. Optical discrimination of surface reflection from volume backscattering in speckle contrast for skin roughness measurements

    Science.gov (United States)

    Tchvialeva, Lioudmila; Zeng, Haishan; Markhvida, Igor; Dhadwal, Gurbir; McLean, Lianne; McLean, David I.; Lui, Harvey; Lee, Tim K.

    2009-02-01

    Background: The intermixing of light reflected from tissue surface and scattered from tissue volume complicates skin surface roughness assessment by laser speckle technique, a non-invasive optical method based on the analysis of the contrast of a speckle pattern. Objective: In this study we investigated optical discrimination methods to separate the two contributions in a speckle pattern. Methods: Three discrimination methods, spatial, polarization and spectral filtering, were implemented to suppress light from skin internal volume in a laser speckle device. In order to determine the effectiveness of the discrimination methods, speckle patterns were obtained from healthy volunteers, and polychromatic speckle contrast was computed before and after each filtering procedure. Results: Speckle contrast increased after discrimination filtering. A simple formula was derived to calculate the speckle contrast associated with light scattered from the skin surface. This corrected speckle contrast was proposed to be used for skin roughness assessment.

  16. Can laser speckle flowmetry be made a quantitative tool?

    Science.gov (United States)

    Duncan, Donald D; Kirkpatrick, Sean J

    2008-08-01

    The ultimate objective of laser speckle flowmetry (and a host of specific implementations such as laser speckle contrast analysis, LASCA or LSCA; laser speckle spatial contrast analysis, LSSCA; laser speckle temporal contrast analysis, LSTCA; etc.) is to infer flow velocity from the observed speckle contrast. Despite numerous demonstrations over the past 25 years of such a qualitative relationship, no convincing quantitative relationship has been proven. One reason is a persistent mathematical error that has been propagated by a host of workers; another is a misconception about the proper autocorrelation function for ordered flow. Still another hindrance has been uncertainty in the specific relationship between decorrelation time and local flow velocity. Herein we attempt to dispel some of these errors and misconceptions with the intent of turning laser speckle flowmetry into a quantitative tool. Specifically we review the underlying theory, explore the impact of various analytic models for relating measured intensity fluctuations to scatterer motion, and address some of the practical issues associated with the measurement and subsequent data processing.

  17. Improvement in White Matter Tract Reconstruction with Constrained Spherical Deconvolution and Track Density Mapping in Low Angular Resolution Data: A Pediatric Study and Literature Review

    Directory of Open Access Journals (Sweden)

    Benedetta Toselli

    2017-08-01

    Full Text Available IntroductionDiffusion-weighted magnetic resonance imaging (DW-MRI allows noninvasive investigation of brain structure in vivo. Diffusion tensor imaging (DTI is a frequently used application of DW-MRI that assumes a single main diffusion direction per voxel, and is therefore not well suited for reconstructing crossing fiber tracts. Among the solutions developed to overcome this problem, constrained spherical deconvolution with probabilistic tractography (CSD-PT has provided superior quality results in clinical settings on adult subjects; however, it requires particular acquisition parameters and long sequences, which may limit clinical usage in the pediatric age group. The aim of this work was to compare the results of DTI with those of track density imaging (TDI maps and CSD-PT on data from neonates and children, acquired with low angular resolution and low b-value diffusion sequences commonly used in pediatric clinical MRI examinations.Materials and methodsWe analyzed DW-MRI studies of 50 children (eight neonates aged 3–28 days, 20 infants aged 1–8 months, and 22 children aged 2–17 years acquired on a 1.5 T Philips scanner using 34 gradient directions and a b-value of 1,000 s/mm2. Other sequence parameters included 60 axial slices; acquisition matrix, 128 × 128; average scan time, 5:34 min; voxel size, 1.75 mm × 1.75 mm × 2 mm; one b = 0 image. For each subject, we computed principal eigenvector (EV maps and directionally encoded color TDI maps (DEC-TDI maps from whole-brain tractograms obtained with CSD-PT; the cerebellar-thalamic, corticopontocerebellar, and corticospinal tracts were reconstructed using both CSD-PT and DTI. Results were compared by two neuroradiologists using a 5-point qualitative score.ResultsThe DEC-TDI maps obtained presented higher anatomical detail than EV maps, as assessed by visual inspection. In all subjects, white matter (WM tracts were successfully reconstructed using both

  18. Programmable color liquid-crystal television spatial light modulator: transmittance properties and application to speckle-correlation displacement measurement.

    Science.gov (United States)

    Aiken, J; Bates, B

    2000-01-10

    Drive electronics developed for a color liquid-crystal television (LCTV) display enable data to be written onto individual pixels. Display transmittance characteristics obtained with the new and the original TV drive electronics are compared. The enhanced performance obtained through this development has some potential for spatial light modulator applications in color, optical information processing based on the low-cost LCTV. As an example, we describe a novel, to our knowledge, speckle metrology technique used to display fringes and to output correlation peaks resulting from in-plane object displacement. This requires only a single LC display to encode, simultaneously in three pixel colors, speckle and fringe patterns for real-time measurements. Relative merits of this technique, including displacement range and temporal resolution, are discussed.

  19. Measurement-based perturbation theory and differential equation parameter estimation for high-precision high-resolution reconstruction of the Earth's gravitational field from satellite tracking measurements

    OpenAIRE

    Xu, Peiliang

    2016-01-01

    The numerical integration method has been routinely used to produce global standard gravitational models from satellite tracking measurements of CHAMP/GRACE types. It is implemented by solving the differential equations of the partial derivatives of a satellite orbit with respect to the unknown harmonic coefficients under the conditions of zero initial values. From the mathematical point of view, satellite gravimetry from satellite tracking is the problem of estimating unknown parameters in t...

  20. Non-contact measurement of ocular microtremor using laser speckle

    Science.gov (United States)

    Kenny, E.; Coakley, D.; Boyle, G.

    2010-04-01

    The human eye moves continuously even while it appears to be at rest. The involuntary eye movements causing this motion are called fixational eye movements. Ocular Microtremor (OMT) is the smallest (150 - 2500nm amplitude) and fastest (~ 80Hz) of these eye movements. OMT has been proven to provide useful clinical information regarding depth of consciousness and neurological disorders. Most quantitative clinical investigations of OMT have been carried out using an eye-contacting piezoelectric probe. However, this measurement procedure suffers from a number of disadvantages which limit the potential of the technique in the clinical environment. The need for eye contact requires the eye to be anaesthetised and not all subjects can tolerate the procedure. A promising alternative to the piezoelectric technique is speckle metrology. A speckle correlation instrument for measuring OMT was first described by Al-Kalbani et al. The approach presented in this paper is a non contact measurement technique implementing laser speckle correlation and using a highly light sensitive video camera operating at 500Hz. The OMT measurement technique in this paper was investigated using a human subject and an eye movement simulator. Using this system, measurement of speckle on the eye takes only a few minutes, no eye drops are necessary and no discomfort is caused to the subject. The paper describes the preliminary results of capturing speckle from the simulator and from the human eye in-vivo at eye safe laser powers. The effects of tear flow, biospeckle and speckle shifting by larger eye movements on the displacement information carried by the speckle are also discussed.

  1. Multi-exposure speckle imaging of cerebral blood flow: a pilot clinical study (Conference Presentation)

    Science.gov (United States)

    Richards, Lisa M.; Kazmi, S. M. S.; Olin, Katherine E.; Waldron, James S.; Fox, Douglas J.; Dunn, Andrew K.

    2017-03-01

    Monitoring cerebral blood flow (CBF) during neurosurgery is essential for detecting ischemia in a timely manner for a wide range of procedures. Multiple clinical studies have demonstrated that laser speckle contrast imaging (LSCI) has high potential to be a valuable, label-free CBF monitoring technique during neurosurgery. LSCI is an optical imaging method that provides blood flow maps with high spatiotemporal resolution requiring only a coherent light source, a lens system, and a camera. However, the quantitative accuracy and sensitivity of LSCI is limited and highly dependent on the exposure time. An extension to LSCI called multi-exposure speckle imaging (MESI) overcomes these limitations, and was evaluated intraoperatively in patients undergoing brain tumor resection. This clinical study (n = 7) recorded multiple exposure times from the same cortical tissue area, and demonstrates that shorter exposure times (≤1 ms) provide the highest dynamic range and sensitivity for sampling flow rates in human neurovasculature. This study also combined exposure times using the MESI model, demonstrating high correlation with proper image calibration and acquisition. The physiological accuracy of speckle-estimated flow was validated using conservation of flow analysis on vascular bifurcations. Flow estimates were highly conserved in MESI and 1 ms exposure LSCI, with percent errors at 6.4% ± 5.3% and 7.2% ± 7.2%, respectively, while 5 ms exposure LSCI had higher errors at 21% ± 10% (n = 14 bifurcations). Results from this study demonstrate the importance of exposure time selection for LSCI, and that intraoperative MESI can be performed with high quantitative accuracy.

  2. Speckle Reduction for Ultrasonic Imaging Using Frequency Compounding and Despeckling Filters along with Coded Excitation and Pulse Compression

    Directory of Open Access Journals (Sweden)

    Joshua S. Ullom

    2012-01-01

    Full Text Available A method for improving the contrast-to-noise ratio (CNR while maintaining the −6 dB axial resolution of ultrasonic B-mode images is proposed. The technique proposed is known as eREC-FC, which enhances a recently developed REC-FC technique. REC-FC is a combination of the coded excitation technique known as resolution enhancement compression (REC and the speckle-reduction technique frequency compounding (FC. In REC-FC, image CNR is improved but at the expense of a reduction in axial resolution. However, by compounding various REC-FC images made from various subband widths, the tradeoff between axial resolution and CNR enhancement can be extended. Further improvements in CNR can be obtained by applying postprocessing despeckling filters to the eREC-FC B-mode images. The despeckling filters evaluated were the following: median, Lee, homogeneous mask area, geometric, and speckle-reducing anisotropic diffusion (SRAD. Simulations and experimental measurements were conducted with a single-element transducer (f/2.66 having a center frequency of 2.25 MHz and a −3 dB bandwidth of 50%. In simulations and experiments, the eREC-FC technique resulted in the same axial resolution that would be typically observed with conventional excitation with a pulse. Moreover, increases in CNR of 348% were obtained in experiments when comparing eREC-FC with a Lee filter to conventional pulsing methods.

  3. High-Resolution Diffusion Tensor MR Imaging for Evaluating Myocardial Anisotropy and Fiber Tracking at 3T: the Effect of the Number of Diffusion- Sensitizing Gradient Directions

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Sang Il; Kang, Joon Won; Lim, Tae Hwan [Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Chun, Eun Ju [Seoul National University Bundang Hospital, Sengnam (Korea, Republic of); Choi, Seong Hoon [Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan (Korea, Republic of)

    2010-02-15

    We wanted to evaluate the effect of the number of diffusion-sensitizing gradient directions on the image quality for evaluating myocardial anisotropy and fiber tracking by using in vitro diffusion tensor MR imaging (DT-MRI). The DT-MR images, using a SENSE-based echoplanar imaging technique, were acquired from ten excised porcine hearts by using a 3T MR scanner. With a b-value of 800 s/mm{sup 2}, the diffusion tensor images were obtained for 6, 15 and 32 diffusion-sensitizing gradient directions at the midventricular level. The number of tracked fibers, the fractional anisotropy (FA), and the length of the tracked fibers were measured for the quantitative analysis. Two radiologists assessed the image quality of the fiber tractography for the qualitative analysis. By increasing the number of diffusion-sensitizing gradient directions from 6 to 15, and then to 32, the FA and standard deviation were significantly reduced (p < 0.01), and the number of tracked fibers and the length of the tracked fibers were significantly increased (p < 0.01). The image quality of the fiber tractography was significantly increased with the increased number of diffusion sensitizing gradient directions (p < 0.01). The image quality of in vitro DT-MRI is significantly improved as the number of diffusion-sensitizing gradient directions is increased.

  4. Dispersion of speckle suppression efficiency for binary DOE structures: spectral domain and coherent matrix approaches.

    Science.gov (United States)

    Lapchuk, Anatoliy; Prygun, Olexandr; Fu, Minglei; Le, Zichun; Xiong, Qiyuan; Kryuchyn, Andriy

    2017-06-26

    We present the first general theoretical description of speckle suppression efficiency based on an active diffractive optical element (DOE). The approach is based on spectral analysis of diffracted beams and a coherent matrix. Analytical formulae are obtained for the dispersion of speckle suppression efficiency using different DOE structures and different DOE activation methods. We show that a one-sided 2D DOE structure has smaller speckle suppression range than a two-sided 1D DOE structure. Both DOE structures have sufficient speckle suppression range to suppress low-order speckles in the entire visible range, but only the two-sided 1D DOE can suppress higher-order speckles. We also show that a linear shift 2D DOE in a laser projector with a large numerical aperture has higher effective speckle suppression efficiency than the method using switching or step-wise shift DOE structures. The generalized theoretical models elucidate the mechanism and practical realization of speckle suppression.

  5. Laser speckle decorrelation for fingerprint acquisition

    Science.gov (United States)

    Schirripa Spagnolo, Giuseppe; Cozzella, Lorenzo

    2012-09-01

    Biometry is gaining popularity as a physical security approach in situations where a high level of security is necessary. Currently, biometric solutions are embedded in a very large and heterogeneous group of applications. One of the most sensible is for airport security access to boarding gates. More airports are introducing biometric solutions based on face, fingerprint or iris recognition for passenger identification. In particular, fingerprints are the most widely used biometric, and they are mandatorily included in electronic identification documents. One important issue, which is difficult to address in traditional fingerprint acquisition systems, is preventing contact between subsequent users; sebum, which can be a potential vector for contagious diseases. Currently, non-contact devices are used to overcome this problem. In this paper, a new contact device based on laser speckle decorrelation is presented. Our system has the advantage of being compact and low-cost compared with an actual contactless system, allowing enhancement of the sebum pattern imaging contrast in a simple and low-cost way. Furthermore, it avoids the spreading of contagious diseases.

  6. Speckle interferometric system to measure ocular microtremor

    Science.gov (United States)

    Ryle, James P.; Al-Kalbani, Mohammed; Collins, Niamh; Gopinathan, Unnikrishnan; Boyle, Gerard; Coakley, Davis; Sheridan, John T.

    2008-04-01

    Ocular microtremor (OMT) is a biological high frequency (up to 150Hz) low amplitude (25-2500nm peak to peak) involuntary motion of the human eye. Clinical OMT investigations to date have used eye-contacting mechanical piezoelectric probes or piezoelectric strain gauges. Before contact can be made, the eye must first be anaesthetized. In some cases, this eyelid spasms occur making it impossible to measure OMT. Using the contact probe method, the eye motion is mechanically loaded. Results from clinical studies with this method to date have given electrical signal amplitudes from the probe proportional to the displacement, but not the exact displacement information. Recent studies suggest a number of clinical applications for OMT, these include monitoring the depth of anesthesia of a patient in surgery, prediction of outcome in coma, diagnosis of brain stem death. In addition to this, in patients with neurological disorders such as Multiple Sclerosis and Parkinson's disease, abnormal OMT frequency content is present. In this paper, we design a compact non-contact phase modulating optical fiber speckle interferometer to measure eye motions. We simulate OMT motion using a calibrated piezoelectric vibration simulator and compare results produced using a contact method with those using our optical non-contact method.

  7. Slab track

    OpenAIRE

    Golob, Tina

    2014-01-01

    The last 160 years has been mostly used conventional track with ballasted bed, sleepers and steel rail. Ensuring the high speed rail traffic, increasing railway track capacities, providing comfortable and safe ride as well as high reliability and availability railway track, has led to development of innovative systems for railway track. The so-called slab track was first built in 1972 and since then, they have developed many different slab track systems around the world. Slab track was also b...

  8. Applicaton of speckle dynamics for studies of cell metabolism

    Science.gov (United States)

    Vladimirov, A. P.; Baharev, A. A.; Malygin, A. S.; Mikhailova, J. A.; Novoselova, I. A.; Yakin, D. I.

    2015-05-01

    Previously, a speckle interferometry technique and a device that allows quantitative evaluation of the metabolic activity of cultured cells were theoretically grounded and successfully tested. A speckle time-averaging technique was proposed to separate and study the processes occurring in cells at various velocities. The objective of the present research was comparing the parameters of speckle dynamics used to evaluate cell metabolism and averaged in areas of various size. Areas inside the speckle image of a cell as well as areas of the image plane with various numbers of cells were averaging areas. The target of the research was cells from L-41 culture placed onto a special optical tray with a nutrient solution immediately after defrosting. Time-average value T of digital radiation intensity in the TV camera pixels I (1) and the correlation coefficient of two digital images η (2) were used as speckle field change parameters. The digital images corresponded to a single frame area at two time moments. It is shown that in the area containing hundreds of cells dependence η(t) levels off, which indicate stationarity of random value I~ . Features of η(t) dependences obtained by averaging over large and small cell numbers image are discussed. Using the data obtained, we formulated recommendations on selecting area sizes for averaging physical values to study various processes occurring in cells.

  9. Analysis of strawberry ripening by dynamic speckle measurements

    Science.gov (United States)

    Mulone, C.; Budini, N.; Vincitorio, F. M.; Freyre, C.; López Díaz, A. J.; Ramil Rego, A.

    2013-11-01

    This work seeks to determine the age of a fruit from observation of its dynamic speckle pattern. A mobile speckle pattern originates on the fruit's surface due to the interference of the wavefronts reflected from moving scatterers. For this work we analyzed two series of photographs of a strawberry speckle pattern, at different stages of ripening, acquired with a CMOS camera. The first day, we took ten photographs at an interval of one second. The same procedure was repeated the next day. From each series of images we extracted several statistical descriptors of pixel-to-pixel gray level variation during the observation time. By comparing these values from the first to the second day we noticed a diminution of the speckle activity. This decay demonstrated that after only one day the ripening process of the strawberry can be detected by dynamic speckle pattern analysis. For this study we employed a simple new algorithm to process the data obtained from the photographs. This algorithm allows defining a global mobility index that indicates the evolution of the fruit's ripening.

  10. Insulator speckles associated with long-distance chromatin contacts.

    Science.gov (United States)

    Buxa, Melanie K; Slotman, Johan A; van Royen, Martin E; Paul, Maarten W; Houtsmuller, Adriaan B; Renkawitz, Rainer

    2016-09-15

    Nuclear foci of chromatin binding factors are, in many cases, discussed as sites of long-range chromatin interaction in the three-dimensional nuclear space. Insulator binding proteins have been shown to aggregate into insulator bodies, which are large structures not involved in insulation; however, the more diffusely distributed insulator speckles have not been analysed in this respect. Furthermore, insulator binding proteins have been shown to drive binding sites for Polycomb group proteins into Polycomb bodies. Here we find that insulator speckles, marked by the insulator binding protein dCTCF, and Polycomb bodies show differential association with the insulator protein CP190. They differ in number and three-dimensional location with only 26% of the Polycomb bodies overlapping with CP190. By using fluorescence in situ hybridization (FISH) probes to identify long-range interaction (kissing) of the Hox gene clusters Antennapedia complex (ANT-C) and Bithorax complex (BX-C), we found the frequency of interaction to be very low. However, these rare kissing events were associated with insulator speckles at a significantly shorter distance and an increased speckle number. This suggests that insulator speckles are associated with long-distance interaction. © 2016. Published by The Company of Biologists Ltd.

  11. Insulator speckles associated with long-distance chromatin contacts

    Science.gov (United States)

    Buxa, Melanie K.; Slotman, Johan A.; van Royen, Martin E.; Paul, Maarten W.; Houtsmuller, Adriaan B.

    2016-01-01

    ABSTRACT Nuclear foci of chromatin binding factors are, in many cases, discussed as sites of long-range chromatin interaction in the three-dimensional nuclear space. Insulator binding proteins have been shown to aggregate into insulator bodies, which are large structures not involved in insulation; however, the more diffusely distributed insulator speckles have not been analysed in this respect. Furthermore, insulator binding proteins have been shown to drive binding sites for Polycomb group proteins into Polycomb bodies. Here we find that insulator speckles, marked by the insulator binding protein dCTCF, and Polycomb bodies show differential association with the insulator protein CP190. They differ in number and three-dimensional location with only 26% of the Polycomb bodies overlapping with CP190. By using fluorescence in situ hybridization (FISH) probes to identify long-range interaction (kissing) of the Hox gene clusters Antennapedia complex (ANT-C) and Bithorax complex (BX-C), we found the frequency of interaction to be very low. However, these rare kissing events were associated with insulator speckles at a significantly shorter distance and an increased speckle number. This suggests that insulator speckles are associated with long-distance interaction. PMID:27464669

  12. Speckle suppression and companion detection using coherent differential imaging

    Science.gov (United States)

    Bottom, M.; Wallace, J. K.; Bartos, R. D.; Shelton, J. C.; Serabyn, E.

    2017-01-01

    Residual speckles due to aberrations arising from optical errors after the split between the wavefront sensor and the science camera path are the most significant barriers to imaging extrasolar planets. While speckles can be suppressed using the science camera in conjunction with the deformable mirror, this requires knowledge of the phase of the electric field in the focal plane. We describe a method which combines a coronagraph with a simple phase-shifting interferometer to measure and correct speckles in the full focal plane. We demonstrate its initial use on the Stellar Double Coronagraph at the Palomar Observatory. We also describe how the same hardware can be used to distinguish speckles from true companions by measuring the coherence of the optical field in the focal plane. We present results observing the brown dwarf HD49197b with this technique, demonstrating the ability to detect the presence of a companion even when it is buried in the speckle noise, without the use of any standard `calibration' techniques. We believe this is the first detection of a substellar companion using the coherence properties of light.

  13. Identification of a chemical inhibitor for nuclear speckle formation: Implications for the function of nuclear speckles in regulation of alternative pre-mRNA splicing

    Energy Technology Data Exchange (ETDEWEB)

    Kurogi, Yutaro; Matsuo, Yota; Mihara, Yuki; Yagi, Hiroaki; Shigaki-Miyamoto, Kaya; Toyota, Syukichi; Azuma, Yuko [Department of Biological Sciences, Graduate School of Science and Technology, Kumamoto University, Chuo-ku, Kumamoto 860-8555 (Japan); Igarashi, Masayuki [Laboratory of Disease Biology, Institute of Microbial Chemistry, Shinagawa-ku, Tokyo 141-0021 (Japan); Tani, Tokio, E-mail: ttani@sci.kumamoto-u.ac.jp [Department of Biological Sciences, Graduate School of Science and Technology, Kumamoto University, Chuo-ku, Kumamoto 860-8555 (Japan)

    2014-03-28

    Highlights: • We identified tubercidin as a compound inducing aberrant formation of the speckles. • Tubercidin causes delocalization of poly (A){sup +}RNAs from nuclear speckles. • Tubercidin induces dispersion of splicing factors from nuclear speckles. • Tubercidin affects alternative pre-mRNA splicing. • Nuclear speckles play a role in regulation of alternative pre-mRNA splicing. - Abstract: Nuclear speckles are subnuclear structures enriched with RNA processing factors and poly (A){sup +} RNAs comprising mRNAs and poly (A){sup +} non-coding RNAs (ncRNAs). Nuclear speckles are thought to be involved in post-transcriptional regulation of gene expression, such as pre-mRNA splicing. By screening 3585 culture extracts of actinomycetes with in situ hybridization using an oligo dT probe, we identified tubercidin, an analogue of adenosine, as an inhibitor of speckle formation, which induces the delocalization of poly (A){sup +} RNA and dispersion of splicing factor SRSF1/SF2 from nuclear speckles in HeLa cells. Treatment with tubercidin also decreased steady-state MALAT1 long ncRNA, thought to be involved in the retention of SRSF1/SF2 in nuclear speckles. In addition, we found that tubercidin treatment promoted exon skipping in the alternative splicing of Clk1 pre-mRNA. These results suggest that nuclear speckles play a role in modulating the concentration of splicing factors in the nucleoplasm to regulate alternative pre-mRNA splicing.

  14. Tracking dynamic team activity

    Energy Technology Data Exchange (ETDEWEB)

    Tambe, M. [Univ. of Southern California, Marina del Rey, CA (United States)

    1996-12-31

    AI researchers are striving to build complex multi-agent worlds with intended applications ranging from the RoboCup robotic soccer tournaments, to interactive virtual theatre, to large-scale real-world battlefield simulations. Agent tracking - monitoring other agent`s actions and inferring their higher-level goals and intentions - is a central requirement in such worlds. While previous work has mostly focused on tracking individual agents, this paper goes beyond by focusing on agent teams. Team tracking poses the challenge of tracking a team`s joint goals and plans. Dynamic, real-time environments add to the challenge, as ambiguities have to be resolved in real-time. The central hypothesis underlying the present work is that an explicit team-oriented perspective enables effective team tracking. This hypothesis is instantiated using the model tracing technology employed in tracking individual agents. Thus, to track team activities, team models are put to service. Team models are a concrete application of the joint intentions framework and enable an agent to track team activities, regardless of the agent`s being a collaborative participant or a non-participant in the team. To facilitate real-time ambiguity resolution with team models: (i) aspects of tracking are cast as constraint satisfaction problems to exploit constraint propagation techniques; and (ii) a cost minimality criterion is applied to constrain tracking search. Empirical results from two separate tasks in real-world, dynamic environments one collaborative and one competitive - are provided.

  15. Dedicated hardware processor and corresponding system-on-chip design for real-time laser speckle imaging.

    Science.gov (United States)

    Jiang, Chao; Zhang, Hongyan; Wang, Jia; Wang, Yaru; He, Heng; Liu, Rui; Zhou, Fangyuan; Deng, Jialiang; Li, Pengcheng; Luo, Qingming

    2011-11-01

    Laser speckle imaging (LSI) is a noninvasive and full-field optical imaging technique which produces two-dimensional blood flow maps of tissues from the raw laser speckle images captured by a CCD camera without scanning. We present a hardware-friendly algorithm for the real-time processing of laser speckle imaging. The algorithm is developed and optimized specifically for LSI processing in the field programmable gate array (FPGA). Based on this algorithm, we designed a dedicated hardware processor for real-time LSI in FPGA. The pipeline processing scheme and parallel computing architecture are introduced into the design of this LSI hardware processor. When the LSI hardware processor is implemented in the FPGA running at the maximum frequency of 130 MHz, up to 85 raw images with the resolution of 640×480 pixels can be processed per second. Meanwhile, we also present a system on chip (SOC) solution for LSI processing by integrating the CCD controller, memory controller, LSI hardware processor, and LCD display controller into a single FPGA chip. This SOC solution also can be used to produce an application specific integrated circuit for LSI processing.

  16. Uncertainty of scattered light roughness measurements based on speckle correlation methods

    Science.gov (United States)

    Patzelt, Stefan; Stöbener, Dirk; Ströbel, Gerald; Fischer, Andreas

    2017-06-01

    Surface micro topography measurement (e.g., form, waviness, roughness) is a precondition to assess the surface quality of technical components with regard to their applications. Well defined, standardized measuring devices measure and specify geometrical surface textures only under laboratory conditions. Laser speckle-based roughness measurement is a parametric optical scattered light measuring technique that overcomes this confinement. Field of view dimensions of some square millimeters and measuring frequencies in the kHz domain enable in-process roughness characterization of even moving part surfaces. However, camera exposure times of microseconds or less and a high detector pixel density mean less light energy per pixel due to the limited laser power. This affects the achievable measurement uncertainty according to the Heisenberg uncertainty principle. The influence of fundamental, inevitable noise sources such as the laser shot noise and the detector noise is not quantified yet. Therefore, the uncertainty for speckle roughness measurements is analytically estimated. The result confirms the expected inverse proportionality of the measurement uncertainty to the square root of the illuminating light power and the direct proportionality to the detector readout noise, quantization noise and dark current noise, respectively. For the first time it is possible to quantify the achievable measurement uncertainty u(Sa) < 1 nm for the scattered light measuring system. The low uncertainty offers ideal preconditions for in-process roughness measurements in an industrial environment with an aspired resolution of 1 nm.

  17. Enhanced tagging of light utilizing acoustic radiation force with speckle pattern analysis

    Science.gov (United States)

    Vakili, Ali; Hollmann, Joseph L.; Holt, R. Glynn; DiMarzio, Charles A.

    2017-10-01

    In optical imaging, the depth and resolution are limited due to scattering. Unlike light, scattering of ultrasound (US) waves in tissue is negligible. Hybrid imaging methods such as US-modulated optical tomography (UOT) use the advantages of both modalities. UOT tags light by inducing phase change caused by modulating the local index of refraction of the medium. The challenge in UOT is detecting the small signal. The displacement induced by the acoustic radiation force (ARF) is another US effect that can be utilized to tag the light. It induces greater phase change, resulting in a stronger signal. Moreover, the absorbed acoustic energy generates heat, resulting in change in the index of refraction and a strong phase change. The speckle pattern is governed by the phase of the interfering scattered waves; hence, speckle pattern analysis can obtain information about displacement and temperature changes. We have presented a model to simulate the insonation processes. Simulation results based on fixed-particle Monte Carlo and experimental results show that the signal acquired by utilizing ARF is stronger compared to UOT. The introduced mean irradiance change (MIC) signal reveals both thermal and mechanical effects of the focused US beam in different timescales. Simulation results suggest that variation in the MIC signal can be used to generate a displacement image of the medium.

  18. Towards non-contact photo-acoustic endoscopy using speckle pattern analysis

    Science.gov (United States)

    Lengenfelder, Benjamin; Mehari, Fanuel; Tang, Yuqi; Klämpfl, Florian; Zalevsky, Zeev; Schmidt, Michael

    2017-03-01

    Photoacoustic Tomography combines the advantages of optical and acoustic imaging as it makes use of the high optical contrast of tissue and the high resolution of ultrasound. Furthermore, high penetration depths in tissue in the order of several centimeters can be achieved by the combination of these modalities. Extensive research is being done in the field of miniaturization of photoacoustic devices, as photoacoustic imaging could be of significant benefits for the physician during endoscopic interventions. All the existing miniature systems are based on contact transducers for signal detection that are placed at the distal end of an endoscopic device. This makes the manufacturing process difficult and impedance matching to the inspected surface a requirement. The requirement for contact limits the view of the physician during the intervention. Consequently, a fiber based non-contact optical sensing technique would be highly beneficial for the development of miniaturized photoacoustic endoscopic devices. This work demonstrates the feasibility of surface displacement detection using remote speckle-sensing using a high speed camera and an imaging fiber bundle that is used in commercially available video endoscopes. The feasibility of displacement sensing is demonstrated by analysis of phantom vibrations which are induced by loudspeaker membrane oscillations. Since the usability of the remote speckle-sensing for photo-acoustic signal detection was already demonstrated, the fiber bundle approach demonstrates the potential for non-contact photoacoustic detections during endoscopy.

  19. Reduction of the recorded speckle noise in holographic 3D printer.

    Science.gov (United States)

    Utsugi, Takeru; Yamaguchi, Masahiro

    2013-01-14

    A holographic 3D printer produces a high-quality 3D image reproduced by a full-color, full-parallax holographic stereogram with high-density light-ray recording. In order to produce a high-resolution holographic stereogram, we have to solve the problem of speckle noise in this system. For equalizing an intensity distribution inside the elementary hologram, the object beam is modulated by a diffuser. However the diffuser typically generates speckles, which is recorded in the holographic stereogram. It is localized behind the reconstructed image as a granularity noise. First we show the problems of some conventional ways for suppressing the granularity noise using a band-limited diffuser, and then we analyze an approach using a moving diffuser for the reduction of this noise. In the result, it is found that recording with a moving diffuser is effective for reducing the granularity noise at infinity of reconstructed image, although an alternative noise occurs. Moreover we propose a new method introducing multiple exposures to suppress the noise effectively.

  20. Basic Technology and Clinical Applications of the Updated Model of Laser Speckle Flowgraphy to Ocular Diseases

    Directory of Open Access Journals (Sweden)

    Tetsuya Sugiyama

    2014-08-01

    Full Text Available Laser speckle flowgraphy (LSFG allows for quantitative estimation of blood flow in the optic nerve head (ONH, choroid and retina, utilizing the laser speckle phenomenon. The basic technology and clinical applications of LSFG-NAVI, the updated model of LSFG, are summarized in this review. For developing a commercial version of LSFG, the special area sensor was replaced by the ordinary charge-coupled device camera. In LSFG-NAVI, the mean blur rate (MBR has been introduced as a new parameter. Compared to the original LSFG model, LSFG-NAVI demonstrates a better spatial resolution of the blood flow map of human ocular fundus. The observation area is 24 times larger than the original system. The analysis software can separately calculate MBRs in the blood vessels and tissues (capillaries of an entire ONH and the measurements have good reproducibility. The absolute values of MBR in the ONH have been shown to linearly correlate with the capillary blood flow. The Analysis of MBR pulse waveform provides parameters including skew, blowout score, blowout time, rising and falling rates, flow acceleration index, acceleration time index, and resistivity index for comparing different eyes. Recently, there have been an increasing number of reports on the clinical applications of LSFG-NAVI to ocular diseases, including glaucoma, retinal and choroidal diseases.

  1. Color speckle measurement errors using system with XYZ filters

    Science.gov (United States)

    Kinoshita, Junichi; Yamamoto, Kazuhisa; Kuroda, Kazuo

    2017-09-01

    Measurement errors of color speckle are analyzed for a measurement system equipped with revolving XYZ filters and a 2D sensor. One of the errors is caused by the filter characteristics unfitted to the ideal color matching functions. The other is caused by uncorrelations among the optical paths via the XYZ filters. The unfitted color speckle errors of all the pixel data can be easily calibrated by conversion between the measured BGR chromaticity triangle and the true triangle obtained by the BGR wavelength measurements. For the uncorrelated errors, the measured BGR chromaticity values spread over around the true values. As a result, it would be more complicated to calibrate the uncorrelated errors, repeating the triangular conversion pixel by pixel. Color speckle and its errors greatly affect also chromaticity measurements and image quality of displays using coherent light sources.

  2. Optical Processing of Speckle Images with Bacteriorhodopsin for Pattern Recognition

    Science.gov (United States)

    Downie, John D.; Tucker, Deanne (Technical Monitor)

    1994-01-01

    Logarithmic processing of images with multiplicative noise characteristics can be utilized to transform the image into one with an additive noise distribution. This simplifies subsequent image processing steps for applications such as image restoration or correlation for pattern recognition. One particularly common form of multiplicative noise is speckle, for which the logarithmic operation not only produces additive noise, but also makes it of constant variance (signal-independent). We examine the optical transmission properties of some bacteriorhodopsin films here and find them well suited to implement such a pointwise logarithmic transformation optically in a parallel fashion. We present experimental results of the optical conversion of speckle images into transformed images with additive, signal-independent noise statistics using the real-time photochromic properties of bacteriorhodopsin. We provide an example of improved correlation performance in terms of correlation peak signal-to-noise for such a transformed speckle image.

  3. Characterization of Layer-Delaminations by Ultrasonic Speckles

    Science.gov (United States)

    Sadjina, Silvester; Hölzl, Patrick; Zagar, Bernhard G.

    2015-02-01

    Combined electrical mechanical and thermal loads influence highly structured specimen over time and might cause a variety of failure modes. Some of these failures can be such as to only gradually diminish the nominal behaviour of the components so one cannot conclude there is no evolving problem if nominal function is observed. Standard non destructive testing methods are only partly able to detect the developing delamination or progressive generation of voids due to stress. These delaminations can cause voids and cracks in the still operative specimen that might never be of any problem in the nominal operating performance but on the other hand they might further the degradation of the component to ultimately result in a catastrophic failure. We investigate the gradual emergence of so called ultrasonic (US) speckles as a hint to degradation processes deep in the volume of the specimen caused by scatterers (small voids or small cracks) that are too small to be directly imaged by ultrasound techniques. However, due to their density evolving over time they expose t.hemselvs by forming US speckles that increase in contrast over time. In this paper we are applying the well known theory on optical laser speckles caused by micro roughness on a specimens surface to the formation of ultrasound speckles caused by randomly distributed sub wavelength scatterers within the volume of a specimen. Both effects are due to random phase variations in the former case operating on laser light caused by height variations of the scattering profile and in the latter case by sound velocity variations along the propagation path within a specimens volume. We can show that the speckle contrast is a good measure of the average total volume of scattering voids and thus of the onset and evolution of delaminations as defined by Goodman of partly developed speckles.

  4. Towards automatic detection of malignant melanoma by laser speckle

    Science.gov (United States)

    Lee, T. K.; Tchvialeva, L.; Lui, H.; Zeng, H.; McLean, D. I.

    2010-09-01

    The incidence of malignant melanoma (MM), the most aggressive and deadly form of skin cancer, has been increasing rapidly since the last few decades. Clinical differentiation between MM and pigmented benign skin lesions based on visual assessment can be challenging because some of benign lesions such as melanocytic lesions (ML) and seborrheic keratoses (SK) resemble MM. In this paper we introduce a novel, non-invasive, "optical biopsy" method based on laser speckle. Propagating inside the skin tissues, photons undergo optical path dispersion due to scattering. Therefore the emerging light loses the initial state of coherence, which influences the backscattered speckle pattern if the light optical path deviation in a tissue is comparable with the length of coherence. Speckle contrast is a measure of this decorrelation process. Histology shows that MM, ML, and SK have diverse morphology. We hypothesized that the morphological differences can be detected by polychromatic speckle, and the technique can be used to differentiate these lesions in vivo. In a study with 12 MMs, 24 MLs, and 37 SKs, we computed the speckle contrast related to their superficial skin region. The mean contrast of MM, ML and SK were 0.78 (standard error (SE) = 0.02, 0.63 (SE = 0.01), and 0.67 (SE = 0.01), respectively. Statistical test showed that there was a significant difference among the contrast of the three types of lesions (p < 0.001, Kruskal-Wallis), and intergroup pair-wise tests showed significant differences in distribution between all three groups. Potentially, speckle imaging can differentiate these lesions.

  5. Anderson localization in optical lattices with speckle disorder

    Energy Technology Data Exchange (ETDEWEB)

    Sucu, Serpil; Aktas, Saban; Okan, S. Erol [Department of Physics, Trakya University, 22030 Edirne (Turkey); Akdeniz, Zehra [Piri Reis University, 34940 Tuzla-Istanbul (Turkey); Vignolo, Patrizia [Universite de Nice-Sophia Antipolis, Institut non Lineaire de Nice, CNRS, 1361 route des Lucioles, F-06560 Valbonne (France)

    2011-12-15

    We study the localization properties of noninteracting waves propagating in a speckle-like potential superposed on a one-dimensional lattice. Using a combined decimation-renormalization procedure, we estimate the localization length for a tight-binding Hamiltonian where site energies are square-sinc-correlated random variables. By decreasing the width of the correlation function, the disorder patterns approach a {delta}-correlated disorder, and the localization length becomes almost energy independent in the strong disorder limit. We show that this regime can be reached for a size of the speckle grains on the order of (lower than) four lattice steps.

  6. Speckle Suppression in Ultrasonic Images Based on Undecimated Wavelets

    Directory of Open Access Journals (Sweden)

    Fabrizio Argenti

    2003-04-01

    Full Text Available An original method to denoise ultrasonic images affected by speckle is presented. Speckle is modeled as a signal-dependent noise corrupting the image. Noise reduction is approached as a Wiener-like filtering performed in a shift-invariant wavelet domain by means of an adaptive rescaling of the coefficients of an undecimated octave decomposition. The scaling factor of each coefficient is calculated from local statistics of the degraded image, the parameters of the noise model, and the wavelet filters. Experimental results demonstrate that excellent background smoothing as well as preservation of edge sharpness and fine details can be obtained.

  7. Enhanced deterministic phase retrieval using a partially developed speckle field

    DEFF Research Database (Denmark)

    Almoro, Percival F.; Waller, Laura; Agour, Mostafa

    2012-01-01

    intensity measurements are recorded at the output plane corresponding to axially-propagated representations of the PDSF in the input plane. The speckle intensity measurements are then used in a conventional transport of intensity equation (TIE) to reconstruct directly the test wavefront. The PDSF in our...... technique increases the dynamic range of the axial intensity derivative for smooth phase objects, resulting in a more robust solution to the TIE. The SLM setup enables a fast and accurate recording of speckle intensity. Experimental results are in good agreement with those obtained using the iterative phase...

  8. Optical vortex metrology based on the core structures of phase singularities in Laguerre-Gauss transform of a speckle pattern.

    Science.gov (United States)

    Wang, Wei; Yokozeki, Tomoaki; Ishijima, Reika; Takeda, Mitsuo; Hanson, Steen G

    2006-10-30

    A new technique for displacement measurement is proposed that makes use of phase singularities in the complex signal generated by a Laguerre-Gauss filter operation applied to a speckle pattern. The core structures of phase singularities are used as unique fingerprints attached to the object surface, and the displacement is determined by tracing the movement of registered phase singularities with their correspondence being identified by the fingerprints. Experimental results for translational and rotational displacement measurements are presented that demonstrate large dynamic range and high spatial resolution of the proposed optical vortex metrology.

  9. Laser speckle reduction based on compressive sensing and edge detection

    Science.gov (United States)

    Wen, Dong-hai; Jiang, Yue-song; Hua, Hou-qiang; Yu, Rong; Gao, Qian; Zhang, Yan-zhong

    2013-09-01

    Polarization active imager technology obtains images encoded by parameters different than just the reflectivity and therefore provides new information on the image. So polarization active imager systems represent a very powerful observation tool. However, automatic interpretation of the information contained in the reflected intensity of the polarization active image data is extremely difficult because of the speckle phenomenon. An approach for speckle reduction of polarization active image based on the concepts of compressive sensing (CS) theory and edge detection. First, A Canny operator is first utilized to detect and remove edges from the polarization active image. Then, a dictionary learning algorithm which is applied to sparse image representation. The dictionary learning problem is expressed as a box-constrained quadratic program and a fast projected gradient method is introduced to solve it. The Gradient Projection for Square Reconstruction (GPSR) algorithm for solving bound constrained quadratic programming to reduce the speckle noise in the polarization active images. The block-matching 3-D (BM3D) algorithm is used to reduce speckle nosie, it works in two steps: The first one uses hard thresholding to build a relatively clean image for estimating statistics, while the second one performs the actual denoising through empirical Wiener filtering in the transform domain. Finally, the removed edges are added to the reconstructed image. Experimental results show that the visual quality and evaluation indexes outperform the other methods with no edge preservation. The proposed algorithm effectively realizes both despeckling and edge preservation and reaches the state-of-the-art performance.

  10. Improved detectability of microcirculatory dynamics by laser speckle flowmetry

    DEFF Research Database (Denmark)

    Postnov, Dmitry D; Sosnovtseva, Olga; Tuchin, Valery V

    2015-01-01

    Mechanisms of renal autoregulation generate oscillations in arterial blood flow at several characteristic frequencies. Full-field laser speckle flowmetry provides a real-time imaging of superficial blood microcirculation. The possibility to detect changes in oscillatory dynamics is an important i...

  11. A method to transfer speckle patterns for digital image correlation

    Science.gov (United States)

    Chen, Zhenning; Quan, Chenggen; Zhu, Feipeng; He, Xiaoyuan

    2015-09-01

    A simple and repeatable speckle creation method based on water transfer printing (WTP) is proposed to reduce artificial measurement error for digital image correlation (DIC). This technique requires water, brush, and a piece of transfer paper that is made of prefabricated decal paper, a protected sheet, and printed speckle patterns. The speckle patterns are generated and optimized via computer simulations, and then printed on the decal paper. During the experiments, operators can moisten the basement with water and the brush, so that digital patterns can be simply transferred to the carriers’ surfaces. Tensile experiments with an extended three-dimensional (3D) DIC system are performed to test and verify the validity of WTP patterns. It is shown that by comparing with a strain gage, the strain error is less than 50με in a uniform tensile test. From five carbon steel tensile experiments, Lüders bands in both WTP patterns and spray paint patterns are demonstrated to propagate symmetrically. In the necking part where the strain is up to 66%, WTP patterns are proved to adhere to the specimens well. Hence, WTP patterns are capable of maintaining coherence and adherence to the specimen surface. The transfer paper, working as the role of strain gage in the electrometric method, will contribute to speckle creation.

  12. Nuclear speckles: molecular organization, biological function and role in disease.

    Science.gov (United States)

    Galganski, Lukasz; Urbanek, Martyna O; Krzyzosiak, Wlodzimierz J

    2017-10-13

    The nucleoplasm is not homogenous; it consists of many types of nuclear bodies, also known as nuclear domains or nuclear subcompartments. These self-organizing structures gather machinery involved in various nuclear activities. Nuclear speckles (NSs) or splicing speckles, also called interchromatin granule clusters, were discovered as sites for splicing factor storage and modification. Further studies on transcription and mRNA maturation and export revealed a more general role for splicing speckles in RNA metabolism. Here, we discuss the functional implications of the localization of numerous proteins crucial for epigenetic regulation, chromatin organization, DNA repair and RNA modification to nuclear speckles. We highlight recent advances suggesting that NSs facilitate integrated regulation of gene expression. In addition, we consider the influence of abundant regulatory and signaling proteins, i.e. protein kinases and proteins involved in protein ubiquitination, phosphoinositide signaling and nucleoskeletal organization, on pre-mRNA synthesis and maturation. While many of these regulatory proteins act within NSs, direct evidence for mRNA metabolism events occurring in NSs is still lacking. NSs contribute to numerous human diseases, including cancers and viral infections. In addition, recent data have demonstrated close relationships between these structures and the development of neurological disorders. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

  13. Atmospheric Noise on the Bispectrum in Optical Speckle Interferometry

    Indian Academy of Sciences (India)

    Administrator

    Atmospheric Noise on the Bispectrum in Optical Speckle. Interferometry. S. N. Karbelkar Joint Astronomy Programme, Physics Department,. Indian Institute of Science, Bangalore 560012. Rajaram Nityananda Raman Research Institute, Bangalore 560080. Received 1987 May 16; accepted 1987 July 27. Abstract. Based on ...

  14. Ultrasound speckle reduction based on fractional order differentiation.

    Science.gov (United States)

    Shao, Dangguo; Zhou, Ting; Liu, Fan; Yi, Sanli; Xiang, Yan; Ma, Lei; Xiong, Xin; He, Jianfeng

    2017-07-01

    Ultrasound images show a granular pattern of noise known as speckle that diminishes their quality and results in difficulties in diagnosis. To preserve edges and features, this paper proposes a fractional differentiation-based image operator to reduce speckle in ultrasound. An image de-noising model based on fractional partial differential equations with balance relation between k (gradient modulus threshold that controls the conduction) and v (the order of fractional differentiation) was constructed by the effective combination of fractional calculus theory and a partial differential equation, and the numerical algorithm of it was achieved using a fractional differential mask operator. The proposed algorithm has better speckle reduction and structure preservation than the three existing methods [P-M model, the speckle reducing anisotropic diffusion (SRAD) technique, and the detail preserving anisotropic diffusion (DPAD) technique]. And it is significantly faster than bilateral filtering (BF) in producing virtually the same experimental results. Ultrasound phantom testing and in vivo imaging show that the proposed method can improve the quality of an ultrasound image in terms of tissue SNR, CNR, and FOM values.

  15. Integration of speckle de-noising and image segmentation using ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science; Volume 122; Issue 3. Integration of speckle de-noising and image segmentation using Synthetic Aperture Radar image for flood extent extraction. J Senthilnath H Vikram Shenoy Ritwik Rajendra S N Omkar V Mani P G Diwakar. Volume 122 Issue 3 June 2013 pp 559-572 ...

  16. Spatial Behaviour of Singularities in Fractal- and Gaussian Speckle Fields

    DEFF Research Database (Denmark)

    Angelsky, Oleg V.; Maksimyak, Alexander P.; Maksimyak, Peter P.

    2009-01-01

    Peculiarities of the spatial behaviour of the dislocation lines resulting from scattering of coherent radiation from random and fractal rough surfaces are studied. The technique of optical correlation is proposed for diagnostics of phase singularities in a complex speckle field by comparing...

  17. Pointwise intensity-based dynamic speckle analysis with binary patterns

    Science.gov (United States)

    Stoykova, Elena; Mateev, Georgy; Nazarova, Dimana; Berberova, Nataliya; Ivanov, Branimir

    2017-06-01

    Non-destructive detection of physical or biological activity through statistical processing of speckle patterns on the surface of diffusely reflecting objects is an area of active research. A lot of pointwise intensity-based algorithms have been proposed over the recent years. Efficiency of these algorithms is deteriorated by the signal-dependent speckle data, non-uniform illumination or varying reflectivity across the object, especially when the number of the acquired speckle patterns is limited. Pointwise processing of a sequence of 2D images is also time-consuming. In this paper, we propose to transform the acquired speckle images into binary patterns by using for a sign threshold the mean intensity value estimated at each spatial point from the temporal sequence of intensities at this point. Activity is characterized by the 2D distribution of a temporal polar correlation function estimated at a given time lag from the binary patterns. Processing of synthetic and experimental data confirmed that the algorithm provided correct activity determination with the same accuracy as the temporal normalized correlation function. It is efficient without the necessity to apply normalization at non-uniform distribution of intensity in the illuminating laser beam and offers acceleration of computation.

  18. Thermoregulation under semi-natural conditions in speckled ...

    African Journals Online (AJOL)

    We recorded body temperature (Tb) in speckled mousebirds (Colius striatus) under semi-natural conditions in outdoor aviaries, and examined interactions between behavioural and metabolic thermoregulation by experimentally manipulating food availability and communal roosting behaviour. When food was available ad ...

  19. Live Cell Imaging of F-actin Dynamics via Fluorescent Speckle Microscopy (FSM)

    Science.gov (United States)

    Lim, James; Danuser, Gaudenz

    2009-01-01

    In this protocol we describe the use of Fluorescent Speckle Microscopy (FSM) to capture high-resolution images of actin dynamics in PtK1 cells. A unique advantage of FSM is its ability to capture the movement and turnover kinetics (assembly/disassembly) of the F-actin network within living cells. This technique is particularly useful in deriving quantitative measurements of F-actin dynamics when paired with computer vision software (qFSM). We describe the selection, microinjection and visualization of fluorescent actin probes in living cells. Importantly, similar procedures are applicable to visualizing other macomolecular assemblies. FSM has been demonstrated for microtubules, intermediate filaments, and adhesion complexes. PMID:19684563

  20. D0 Central Tracking Chamber Performance Studies

    Energy Technology Data Exchange (ETDEWEB)

    Pizzuto, Domenico [State Univ. of New York (SUNY), Stony Brook, NY (United States)

    1991-01-01

    The performance of the completed DO central tracking chamber was studied using cosmic rays at the State University of New York at Stony Brook. Also studied was a prototype tracking chamber identical in design to the completed DO tracking chamber. The prototype chamber was exposed to a collimated beam of 150 GeV pions at the Fermilab NWA test facility. Results indicate an $R\\Phi$ tracking resolution compatible with the limitations imposed by physical considerations, excellent 2 track resolution, and a high track reconstruction efficiency along with a good rejection power against $\\gamma \\to e^+ e^-$ events.

  1. D0 central tracking chamber performance studies

    Energy Technology Data Exchange (ETDEWEB)

    Pizzuto, Domenico [State Univ. of New York, Stony Brook, NY (United States)

    1991-12-01

    The performance of the completed DO central tracking chamber was studied using cosmic rays at the State University of New York at Stony Brook. Also studied was a prototype tracking chamber identical in design to the completed DO tracking chamber. The prototype chamber was exposed to a collimated beam of 150 GeV pions at the Fermilab NWA test facility. Results indicate an RΦ tracking resolution compatible with the limitations imposed by physical considerations, excellent 2 track resolution, and a high track reconstruction efficiency along with a good rejection power against γ → e + e- events.

  2. Laser speckle reduction techniques for mid-infrared microscopy and stand-off spectroscopy

    Science.gov (United States)

    Furstenberg, Robert; Kendziora, Christopher A.; Breshike, Christopher J.; Nguyen, Viet; McGill, R. Andrew

    2017-05-01

    Due to their high brightness, infrared (IR) lasers (such as tunable quantum cascade lasers, QCLLs) are very attractive illumination sources in both stand-off spectroscopy and micro-spectroscopy. In fact, they are the enabling device for trace-level spectroscopy. However, due to their high coherence as laser beams, QCLLs can cause speckle, especially when illuminating a rough surface. This is highly detrimental to the signal-to-noise ratio (SNR) of thee collected spectra and can easily negate the gains from using aa high brightness source. In most cases, speckle reduction is performed at the expense of optical power. In this paper, we examine several speckle reduction approaches and evaluate them for their ability to reduce speckle contrast while at the same time preserving aa high optical throughput. We analyze multi-mode fibers, integrating spheres, and stationary and moving diffusers for their speckle reduction potential. Speckle-contrast is measured directly by acquiring beam profiles of the illumination beam or, indirectly, by observing speckle formation from illuminating a rough surface (e.g. Infragold® coated surface) with an IR micro-bolometer camera. We also report on a novel speckle-reducing device with increased optical throughput. We characterize speckle contrast reduction from spatial, temporal and wavelength averaging for both CWW and pulsed QCLs. Examples of effect of speckle-reduction on hyperspectral images in both standoff and microscopy configurations are given.

  3. Understanding the exposure-time effect on speckle contrast measurements for laser displays

    Science.gov (United States)

    Suzuki, Koji; Kubota, Shigeo

    2017-09-01

    To evaluate the influence of exposure time on speckle noise for laser displays, speckle contrast measurement method was developed observable at a human eye response time using a high-sensitivity camera which has a signal multiplying function. The nonlinearity of camera light sensitivity was calibrated to measure accurate speckle contrasts, and the measuring lower limit noise of speckle contrast was improved by applying spatial-frequency low pass filter to the captured images. Three commercially available laser displays were measured over a wide range of exposure times from tens of milliseconds to several seconds without adjusting the brightness of laser displays. The speckle contrast of raster-scanned mobile projector without any speckle-reduction device was nearly constant over various exposure times. On the contrary to this, in full-frame projection type laser displays equipped with a temporally-averaging speckle-reduction device, some of their speckle contrasts close to the lower limits noise were slightly increased at the shorter exposure time due to the noise. As a result, the exposure-time effect of speckle contrast could not be observed in our measurements, although it is more reasonable to think that the speckle contrasts of laser displays, which are equipped with the temporally-averaging speckle-reduction device, are dependent on the exposure time. This discrepancy may be attributed to the underestimation of temporal averaging factor. We expected that this method is useful for evaluating various laser displays and clarify the relationship between the speckle noise and the exposure time for a further verification of speckle reduction.

  4. Gigavision - A weatherproof, multibillion pixel resolution time-lapse camera system for recording and tracking phenology in every plant in a landscape

    Science.gov (United States)

    Brown, T.; Borevitz, J. O.; Zimmermann, C.

    2010-12-01

    We have a developed a camera system that can record hourly, gigapixel (multi-billion pixel) scale images of an ecosystem in a 360x90 degree panorama. The “Gigavision” camera system is solar-powered and can wirelessly stream data to a server. Quantitative data collection from multiyear timelapse gigapixel images is facilitated through an innovative web-based toolkit for recording time-series data on developmental stages (phenology) from any plant in the camera’s field of view. Gigapixel images enable time-series recording of entire landscapes with a resolution sufficient to record phenology from a majority of individuals in entire populations of plants. When coupled with next generation sequencing, quantitative population genomics can be performed in a landscape context linking ecology and evolution in situ and in real time. The Gigavision camera system achieves gigapixel image resolution by recording rows and columns of overlapping megapixel images. These images are stitched together into a single gigapixel resolution image using commercially available panorama software. Hardware consists of a 5-18 megapixel resolution DSLR or Network IP camera mounted on a pair of heavy-duty servo motors that provide pan-tilt capabilities. The servos and camera are controlled with a low-power Windows PC. Servo movement, power switching, and system status monitoring are enabled with Phidgets-brand sensor boards. System temperature, humidity, power usage, and battery voltage are all monitored at 5 minute intervals. All sensor data is uploaded via cellular or 802.11 wireless to an interactive online interface for easy remote monitoring of system status. Systems with direct internet connections upload the full sized images directly to our automated stitching server where they are stitched and available online for viewing within an hour of capture. Systems with cellular wireless upload an 80 megapixel “thumbnail” of each larger panorama and full-sized images are manually

  5. Origin of the water vapor responsible for the European extreme rainfalls of August 2002: 1. High-resolution simulations and tracking of air masses

    Science.gov (United States)

    Gangoiti, G.; SáEz de CáMara, E.; Alonso, L.; Navazo, M.; Gómez, M. C.; Iza, J.; GarcíA, J. A.; Ilardia, J. L.; MilláN, M. M.

    2011-11-01

    This article investigates an extreme rainfall event occurred over wide areas of central Europe on August 11-13, 2002. By using a synergistic approach that includes regional modeling, air mass tracking, and observational data sets, the importance of moisture accumulation processes in the Western Mediterranean basin (WMB) is acknowledged as an important mechanism responsible for the magnitude of this event. The RAMS-HYPACT modeling system is used to track air masses from potential marine sources of evaporation. MODIS water vapor products, wind profilers and surface rain gauge measurements are used to substantiate our simulations. Results show that most of the precipitation occurring in central Europe during the initiation of the rainfall episode (August 11) came from vapor accumulated over 4 days (August 6-9) within the WMB: the vapor was transported, after the irruption of the Vb cyclone Ilse, through the Italian Peninsula and the Adriatic Sea, into the target area, causing the precipitation episode. On August 12 and 13 the marine sources of evaporation changed to include the north-Atlantic region. The north-African convergence region, the eastern Mediterranean and the Black Sea are revealed to be sources more related to the intense rainfall experienced in eastern Europe. The subsidence-related processes through which pollutants and water vapor can accumulate for several days in the WMB are shown to be very relevant for this event. The quantification of the evaporative sources, responsible for the extreme rainfall events in central Europe, and the relative importance of marine and terrestrial sources within a chosen regional domain are discussed in the companion following article.

  6. Online Tracking

    Science.gov (United States)

    ... for other purposes, such as research, measurement, and fraud prevention. Mobile browsers work much like traditional web ... users’ Do Not Track preferences. Can I block online tracking? Consumers can learn about tracker-blocking browser ...

  7. A novel method for repeatedly generating speckle patterns used in digital image correlation

    Science.gov (United States)

    Zhang, Juan; Sweedy, Ahmed; Gitzhofer, François; Baroud, Gamal

    2018-01-01

    Speckle patterns play a key role in Digital Image Correlation (DIC) measurement, and generating an optimal speckle pattern has been the goal for decades now. The usual method of generating a speckle pattern is by manually spraying the paint on the specimen. However, this makes it difficult to reproduce the optimal pattern for maintaining identical testing conditions and achieving consistent DIC results. This study proposed and evaluated a novel method using an atomization system to repeatedly generate speckle patterns. To verify the repeatability of the speckle patterns generated by this system, simulation and experimental studies were systematically performed. The results from both studies showed that the speckle patterns and, accordingly, the DIC measurements become highly accurate and repeatable using the proposed atomization system.

  8. Exploiting the sparsity of edge information in synthetic aperture radar imagery for speckle reduction

    Science.gov (United States)

    Scarnati, Theresa; Zelnio, Edmund; Paulson, Christopher

    2017-04-01

    Synthetic aperture radar (SAR) images are corrupted with speckle noise, which manifests as a multiplicative gamma noise and reduces the contrast in imagery, making detection and classifi- cation using SAR images a difficult task. Many speckle reduction techniques aim to reduce this noise without including available prior knowledge about the speckle and the scene contents. In this investigation, we develop a new technique for speckle reduction which incorporates both the statistical model of speckle and the a priori knowledge about the sparsity of edges present in the scene. Using the proposed technique, we despeckle a synthetic image, a SAR image from the MSTAR data set and a SAR image from the Gotcha data set. Our results show that, with our method, we are able to visually improve the quality of SAR images. We show quantitatively that we are able to reduce speckle in homogeneous areas beyond comparable methods, while maintaining edge and target intensity information.

  9. Speckle filtering method of ultrasonic cardio-image based on mathematical morphology

    Science.gov (United States)

    Liu, Qi; Wang, Tianfu; Zheng, Changqiong; Li, Deyu; Zheng, Yi

    2001-09-01

    During the ultrasonic cardio-image 3-D reconstruction, one of the difficult problems is that there are some speckles that show strongly variance of image gray level, the speckles reduce the space difference and remain the detailed structure under cover. The filtering technology can be classified into space domain filtering and frequency domain filtering, and spatial filtering methods have been widely used in ultrasonic medical image processing, according to the statistical characteristic of the speckle, the speckle filtering method based on multidirectional morphological structure is presented. The experiment shows that the speckle noise has been filtered and image details have been preserved by the method based on local statistical property of the image, certainly the speckle filtering is not the final objective and would like to be proved and perfected in the further research of ultrasonic image segmentation and analyzing.

  10. Speckle-interferometric measurement system of 3D deformation to obtain thickness changes of thin specimen under tensile loads

    Science.gov (United States)

    Kowarsch, Robert; Zhang, Jiajun; Sguazzo, Carmen; Hartmann, Stefan; Rembe, Christian

    2017-06-01

    The analysis of materials and geometries in tensile tests and the extraction of mechanic parameters is an important field in solid mechanics. Especially the measurement of thickness changes is important to obtain accurate strain information of specimens under tensile loads. Current optical measurement methods comprising 3D digital image correlation enable thickness-change measurement only with nm-resolution. We present a phase-shifting electronic speckle-pattern interferometer in combination with speckle-correlation technique to measure the 3D deformation. The phase-shift for the interferometer is introduced by fast wavelength tuning of a visible diode laser by injection current. In a post-processing step, both measurements can be combined to reconstruct the 3D deformation. In this contribution, results of a 3Ddeformation measurement for a polymer membrane are presented. These measurements show sufficient resolution for the detection of 3D deformations of thin specimen in tensile test. In future work we address the thickness changes of thin specimen under tensile loads.

  11. Predicting Human Mobility Patterns in Marine Ecosystems: Entropy and Home Range Calculations Based on High-Resolution Fishing Vessel Tracking Data

    Science.gov (United States)

    Murawski, S. A.

    2016-02-01

    A number of recent studies have developed metrics of human mobility patterns based on georeferenced cell phone records. The studies generally indicate a high degree of predictability in human location and relatively narrow home ranges for most people. In marine ecosystems there are a number of important uses for such calculations including marine spatial planning and predicting the impacts of marine management options such as establishing marine protected areas (MPAs). In this study we use individual fishing vessel satellite tracking (VMS) records ( 30 million records) obtained from commercial reef fish fishing vessels in the Gulf of Mexico during 2006-2014. This period witnessed the establishment of a variety of new regulations including individual fishing quotas (IFQs) for snapper, grouper, and tilefish, establishment of spatial-area closures, and the temporary closure of as much as 85,000 nautical miles of productive fishing grounds associated with the Deepwater Horizon oil spill accident. Vessel positions were obtained, with a location frequency of one hour. From these VMS data we calculated three measures of entropy (degree of repeatability in spatial use), as well as calculated the axis of gyration (home range) for each vessel in the data set. These calculations were related to a variety of descriptor variables including vessel size, distance from home port to predominant fishing grounds, revenue generated on fishing trips, and fishing regulations. The applicability of these calculations to marine resource management applications is discussed.

  12. Electronic Speckle Pattern Shearing Interferometry using Photopolymer Diffractive Optical Elements for Vibration Measurements

    OpenAIRE

    Mihaylova, Emilia; Naydenova, Izabela; Martin, Suzanne; Toal, Vincent

    2004-01-01

    Electronic speckle pattern shearing interferometry (ESPSI) is superior to Electronic speckle pattern interferometry (ESPI) when strain distribution, arising from object deformation or vibration, need to be measured. This is because shearography provides data directly related to the spatial derivatives of the displacement. Further development of ESPSI systems could be beneficial for wider application to the measurement of mechanical characteristics of vibrating objects. Two electronic speckle ...

  13. Optical design of the comet Shoemaker-Levy speckle camera

    Energy Technology Data Exchange (ETDEWEB)

    Bissinger, H. [Lawrence Livermore National Lab., CA (United States)

    1994-11-15

    An optical design is presented in which the Lick 3 meter telescope and a bare CCD speckle camera system was used to image the collision sites of the Shoemaker-Levy 9 comet with the Planet Jupiter. The brief overview includes of the optical constraints and system layout. The choice of a Risley prism combination to compensate for the time dependent atmospheric chromatic changes are described. Plate scale and signal-to-noise ratio curves resulting from imaging reference stars are compared with theory. Comparisons between un-corrected and reconstructed images of Jupiter`s impact sites. The results confirm that speckle imaging techniques can be used over an extended time period to provide a method to image large extended objects.

  14. Tinea nigra presenting speckled or "salt and pepper" pattern.

    Science.gov (United States)

    Rossetto, André Luiz; Cruz, Rosana Cé Bella; Haddad, Vidal Junior

    2014-06-01

    A 7-year-old Caucasian female resident of the southern coast of Brazil presented dark spots on the left palm that converged to a unique macule with speckled pattern at about 1 month. The mycological exam and the fungi culture were typical of Hortaea werneckii, the agent of the superficial mycosis Tinea nigra. The patient received butenafine hydrochloride 1% for 30 days, resulting in a complete remission of the lesion. At a follow-up visit 12 months after treatment, there was no lesion recurrence. We describe a form of rare geographical Tinea nigra with a speckled pattern. The "salt and pepper" aspect should be taken into consideration when the mycosis was suspected. © The American Society of Tropical Medicine and Hygiene.

  15. Particle tracking

    CERN Document Server

    Safarík, K; Newby, J; Sørensen, P

    2002-01-01

    In this lecture we will present a short historical overview of different tracking detectors. Then we will describe currently used gaseous and silicon detectors and their performance. In the second part we will discuss how to estimate tracking precision, how to design a tracker and how the track finding works. After a short description of the LHC the main attention is drawn to the ALICE experiment since it is dedicated to study new states in hadronic matter at the LHC. The ALICE tracking procedure is discussed in detail. A comparison to the tracking in ATLAS, CMS and LHCb is given. (5 refs).

  16. Photopolymer diffractive optical elements in electronic speckle pattern shearing interferometry

    Science.gov (United States)

    Mihaylova, Emilia; Naydenova, Izabela; Duignan, Barry; Martin, Suzanne; Toal, Vincent

    2006-09-01

    In this paper we present an electronic speckle pattern shearing interferometer using a photopolymer diffractive optical element in the form of a holographic grating, in combination with a ground glass to shear the images. The sheared images on the ground glass are further imaged onto a CCD camera. The distance between the grating and the ground glass can be used to control the shear and to vary the sensitivity of the system. The direction of sensitivity is easily controlled by rotation of the diffraction grating around its normal. Introducing photopolymer holographic gratings in ESPSI gives the advantage of using high aperture optical elements at relatively low cost. The fact that the diffractive optical element is a photopolymer layer on glass substrate with thickness of 2 mm makes for a compact optical system. The system was successfully used for detection of the resonant frequencies of a vibrating object. Most of the published work on vibration analysis is analytical. Very few experimental results are available in the literature. The well known laser Doppler vibrometers (LDV) and accelerometers used for modal analysis are pointwise measurement techniques, although multipoint LDV is available at significant cost. Electronic speckle pattern techniques suitable for experimental detection of the resonant frequencies of vibrating objects are very promising for vibration analysis because they are whole field and non-contact. A finite element model is developed for prediction of the vibration modes of the object under test. Detection of vibrational modes of aluminium diaphragm is demonstrated and compared with the theoretical model. The results obtained are very promising for future application of ESPSI systems with HOEs, for modal analysis. A significant advantage of shearography over electronic speckle pattern interferometry is that ESPSI is relatively insensitive to external disturbances. Another advantage of the proposed system is that it could be easily converted

  17. Wedge Prism for Direction Resolved Speckle Correlation Interferometry

    Energy Technology Data Exchange (ETDEWEB)

    Pechersky, M.J.

    1999-01-20

    The role of a wedge prism for strain sign determination and enhancing the sensitivity for sub-fringe changes is emphasized. The design and incorporation aspects for in-plane sensitive interferometers have been described in detail. Some experimental results dealing with stress determination by laser annealing and speckle corelation interferometry are presented. The prism can also be applied to produce standardized carrier fringes in spatial phase shifting interferometry.

  18. Discrimination of motile bacteria from filamentous fungi using dynamic speckle

    Science.gov (United States)

    Murialdo, Silvia E.; Passoni, Lucía I.; Guzman, Marcelo N.; Sendra, G. Hernán; Rabal, Héctor; Trivi, Marcelo; Gonzalez, J. Froilán

    2012-05-01

    We present a dynamic laser speckle method to easily discriminate filamentous fungi from motile bacteria in soft surfaces, such as agar plate. The method allows the detection and discrimination between fungi and bacteria faster than with conventional techniques. The new procedure could be straightforwardly extended to different micro-organisms, as well as applied to biological and biomedical research, infected tissues analysis, and hospital water and wastewaters studies.

  19. Speckle imaging with the PAPA detector. [Precision Analog Photon Address

    Science.gov (United States)

    Papaliolios, C.; Nisenson, P.; Ebstein, S.

    1985-01-01

    A new 2-D photon-counting camera, the PAPA (precision analog photon address) detector has been built, tested, and used successfully for the acquisition of speckle imaging data. The camera has 512 x 512 pixels and operates at count rates of at least 200,000/sec. In this paper, technical details on the camera are presented and some of the laboratory and astronomical results are included which demonstrate the detector's capabilities.

  20. Speckle Reduction in Double-Pass Retinal Images Using Variable-Focus Lenses

    Science.gov (United States)

    García-Guerra, C. E.; Aldaba, M.; Arjona, M.; Pujol, J.

    2015-01-01

    Speckle arises in double-pass images when coherent light is scattered by the retina. Since this noise degrades the images that are used to characterize the eye, there is special attention in reducing speckle when working with instruments based on retina reflections. In this work, we present a method for speckle reduction in double-pass retinal images by producing minor periodic variations in the vergence of the beam entering the eye with a variable-focus lens during image recording. Measurements in an artificial and a real eye following the implementation of the method corroborate the speckle reduction.

  1. Tracking Land Use/Land Cover Dynamics in Cloud Prone Areas Using Moderate Resolution Satellite Data: A Case Study in Central Africa

    Directory of Open Access Journals (Sweden)

    Bikash Basnet

    2015-05-01

    Full Text Available Tracking land surface dynamics over cloud prone areas with complex mountainous terrain is an important challenge facing the Earth Science community. One such region is the Lake Kivu region in Central Africa. We developed a processing chain to systematically monitor the spatio-temporal land use/land cover dynamics of this region over the years 1988, 2001, and 2011 using Landsat data, complemented by ancillary data. Topographic compensation was performed on Landsat reflectances to avoid the strong illumination angle impacts and image compositing was used to compensate for frequent cloud cover and thus incomplete annual data availability in the archive. A systematic supervised classification was applied to the composite Landsat imagery to obtain land cover thematic maps with overall accuracies of 90% and higher. Subsequent change analysis between these years found extensive conversions of the natural environment as a result of human related activities. The gross forest cover loss for 1988–2001 and 2001–2011 period was 216.4 and 130.5 thousand hectares, respectively, signifying significant deforestation in the period of civil war and a relatively stable and lower deforestation rate later, possibly due to conservation and reforestation efforts in the region. The other dominant land cover changes in the region were aggressive subsistence farming and urban expansion displacing natural vegetation and arable lands. Despite limited data availability, this study fills the gap of much needed detailed and updated land cover change information for this biologically important region of Central Africa. These multi-temporal datasets will be a valuable baseline for land use managers in the region interested in developing ecologically sustainable land management strategies and measuring the impacts of biodiversity conservation efforts.

  2. The hatching results of indigenous Hungarian speckled hens

    Directory of Open Access Journals (Sweden)

    Ákos Benk

    2016-05-01

    Full Text Available In the pilot farm of Szeged University Faculty of Agriculture we keep two varieties of the Hungarian speckled hen, the feathered-neck variant and the naked-neck type since 1977. The three colour variations of the domestic hen species were bred from the Hungarian lea-land bird by the middle of the 20th Century. Because of the spread of intensive poultry keeping the population of this species has become endangered. Programs supporting ecological-biological farming that began in the last two decades placed the domestically bred birds in the forefront both as purebreds and as candidates in projects for developing merchandisable bio-poultry. Beside the gene preservation, we endeavor to find the best way for the production-purpose utilisation of the speckled hen stock. On the basis of our experiments the laying hens can be used in small scale egg production. We examined the hatching results of both type of speckled hens, during more than 20 generations.

  3. SFADI: The Speckle-free Angular Differential Imaging Method

    Science.gov (United States)

    Li Causi, Gianluca; Stangalini, Marco; Antoniucci, Simone; Pedichini, Fernando; Mattioli, Massimiliano; Testa, Vincenzo

    2017-11-01

    We present a new processing technique that significantly improves the angular differential imaging method (ADI). Its context of application is that of high-contrast imaging of faint objects nearby bright stars in observations obtained with extreme adaptive optics (EXAO) systems. This technique, named “SFADI” for “Speckle-Free ADI,” improves the achievable contrast by means of speckles identification and suppression. This is possible in very high cadence data, which freeze the atmospheric evolution. Here we present simulations in which synthetic planets are injected into a real millisecond frame rate sequence, acquired at the LBT telescope at a visible wavelength, and show that this technique can deliver a low and uniform background, allowing for unambiguous detection of 10‑5 contrast planets, from 100 to 300 mas separations, under poor and highly variable seeing conditions (0.8 to 1.5 arcsec FWHM) and in only 20 minutes of acquisition. A comparison with a standard ADI approach shows that the contrast limit is improved by a factor of 5. We extensively discuss the SFADI dependence on the various parameters like the speckle identification threshold, frame integration time, and number of frames, as well as its ability to provide high-contrast imaging for extended sources and also to work with fast acquisitions.

  4. Community Radiative Transfer Model Applications - A Study of the Retrieval of Trace Gases in the Atmosphere from Cross-track Infrared Sounder (CrIS) Data of a Full-spectral Resolution

    Science.gov (United States)

    Liu, Q.; Nalli, N. R.; Tan, C.; Zhang, K.; Iturbide, F.; Wilson, M.; Zhou, L.

    2015-12-01

    The Community Radiative Transfer Model (CRTM) [3] operationally supports satellite radiance assimilation for weather forecasting, sensor data verification, and the retrievals of satellite products. The CRTM has been applied to UV and visible sensors, infrared and microwave sensors. The paper will demonstrate the applications of the CRTM, in particular radiative transfer in the retrieva algorithm. The NOAA Unique CrIS/ATMS Processing System (NUCAPS) operationally generates vertical profiles of atmospheric temperature (AVTP) and moisture (AVMP) from Suomi NPP Cross-track Infrared Sounder (CrIS) and Advanced Technology Microwave Sounder (ATMS) measurements. Current operational CrIS data have reduced spectral resolution: 1.25 cm-1 for a middle wave band and 2.5 cm-1 for a short-wave wave band [1]. The reduced spectral data largely degraded the retrieval accuracy of trace gases. CrIS full spectral data are also available now which have single spectral resolution of 0.625 cm-1 for all of the three bands: long-wave band, middle wave band, and short-wave band. The CrIS full-spectral resolution data is critical to the retrieval of trace gases such as O3, CO [2], CO2, and CH4. In this paper, we use the Community Radiative Transfer Model (CRTM) to study the impact of the CrIS spectral resolution on the retrieval accuracy of trace gases. The newly released CRTM version 2.2.1 can simulates Hamming-apodized CrIS radiance of a full-spectral resolution. We developed a small utility that can convert the CRTM simulated radiance to un-apodized radiance. The latter has better spectral information which can be helpful to the retrievals of the trace gases. The retrievals will be validated using both NWP model data as well as the data collected during AEROSE expeditions [4]. We will also discuss the sensitivity on trace gases between apodized and un-apodized radiances. References[1] Gambacorta, A., et al.(2013), IEEE Lett., 11(9), doi:10.1109/LGRS.2014.230364, 1639-1643. [2] Han, Y., et

  5. High-resolution 3D coronary vessel wall imaging with near 100% respiratory efficiency using epicardial fat tracking: reproducibility and comparison with standard methods.

    Science.gov (United States)

    Scott, Andrew D; Keegan, Jennifer; Firmin, David N

    2011-01-01

    To quantitatively assess the performance and reproducibility of 3D spiral coronary artery wall imaging with beat-to-beat respiratory-motion-correction (B2B-RMC) compared to navigator gated 2D spiral and turbo-spin-echo (TSE) acquisitions. High-resolution (0.7 × 0.7 mm) cross-sectional right coronary wall acquisitions were performed in 10 subjects using four techniques (B2B-RMC 3D spiral with alternate (2RR) and single (1RR) R-wave gating, navigator-gated 2D spiral (2RR) and navigator-gated 2D TSE (2RR)) on two occasions. Wall thickness measurements were compared with repeated measures analysis of variance (ANOVA). Reproducibility was assessed with the intraclass correlation coefficient (ICC). In all, 91% (73/80) of acquisitions were successful (failures: four TSE, two 3D spiral (1RR) and one 3D spiral (2RR)). Respiratory efficiency of the B2B-RMC was less variable and substantially higher than for navigator gating (99.6 ± 1.2% vs. 39.0 ± 7.5%, P B2B-RMC permits coronary vessel wall assessment over multiple thin contiguous slices in a clinically feasible duration. Excellent reproducibility of the technique potentially enables studies of disease progression/regression. Copyright © 2010 Wiley-Liss, Inc.

  6. REDUCTION OF SPECKLE NOISE BY USING AN ADAPTIVE WINDOW REDUCCIÓN DE RUIDO SPECKLE EMPLEANDO UNA VENTANA ADAPTATIVA

    Directory of Open Access Journals (Sweden)

    Jorge Quiñones

    2012-06-01

    Full Text Available Speckle noise is a multiplicative noise that results from random fluctuations of signals when they are reflected on a surface. This research article proposes a technique to reduce speckle noise by using classic statistical filters and a size-adaptive window. The advantage of using the mentioned window is that such filters show adequate performance at reducing noise and preserving edges. In fact, the results show that the measurement of absolute performance that can be obtained with this window is better than the best results when the window is not used. Such better performance is expressed in terms of the signal / noise ratio, the edge improvement index and the mean square error.El ruido speckle es un ruido multiplicativo que resulta de las fluctuaciones aleatorias de las señales reflejadas en una superficie. En este artículo se propone una técnica de reducción de ruido speckle mediante el uso de los filtros estadísticos clásicos pero empleando una ventana de tamaño adaptativo. La ventaja de utilizar esta ventana es que los filtros tienen un adecuado desempeño en cuanto a reducción de ruido y preservación de contornos. En efecto, los resultados muestran que con esta ventana se obtiene una medida de desempeño absoluto superior a los mejores resultados cuando no se usa esta ventana. Este mejor desempeño es en términos de la relación señal a ruido, del índice de mejora de los contornos y del error cuadrático medio.

  7. Effects of the source, surface, and sensor couplings and colorimetric of laser speckle pattern on the performance of optical imaging system

    Science.gov (United States)

    Darwiesh, M.; El-Sherif, Ashraf F.; El-Ghandour, Hatem; Aly, Hussein A.; Mokhtar, A. M.

    2011-03-01

    Optical imaging systems are widely used in different applications include tracking for portable scanners; input pointing devices for laptop computers, cell phones, and cameras, fingerprint-identification scanners, optical navigation for target tracking, and in optical computer mouse. We presented an experimental work to measure and analyze the laser speckle pattern (LSP) produced from different optical sources (i.e. various color LEDs, 3 mW diode laser, and 10mW He-Ne laser) with different produced operating surfaces (Gabor hologram diffusers), and how they affects the performance of the optical imaging systems; speckle size and signal-to-noise ratio (signal is represented by the patches of the speckles that contain or carry information, and noise is represented by the whole remaining part of the selected image). The theoretical and experimental studies of the colorimetry (color correction is done in the color images captured by the optical imaging system to produce realistic color images which contains most of the information in the image by selecting suitable gray scale which contains most of the informative data in the image, this is done by calculating the accurate Red-Green-Blue (RGB) color components making use of the measured spectrum for light sources, and color matching functions of International Telecommunication Organization (ITU-R709) for CRT phosphorus, Tirinton-SONY Model ) for the used optical sources are investigated and introduced to present the relations between the signal-to-noise ratios with different diffusers for each light source. The source surface coupling has been discussed and concludes that the performance of the optical imaging system for certain source varies from worst to best based on the operating surface. The sensor /surface coupling has been studied and discussed for the case of He-Ne laser and concludes the speckle size is ranged from 4.59 to 4.62 μm, which are slightly different or approximately the same for all produced

  8. Muon Track Matching

    CERN Document Server

    Benvenuti, Alberto C; Genchev, V; Khanov, A I; Stepanov, N; Vankov, P

    2000-01-01

    For most physical processes the tracks observed in the muon stations must be matched with the corresponding tracks in the inner tracker, the external muon system providing muon identification and triggering but the tracker points giving the precise momentum measurement at lower momenta. For high momenta the momentum resolution is much improved by the interconnection of inner and outer measurements. The matching of outer and inner measurements is more delicate in case of muons embedded in jets. A study of the matching procedure was carried out using samples of (b, anti b) jets at high Pt, requiring (b, anti b) -> mu decays.

  9. Controlling the evolution of nondiffracting speckle by complex amplitude modulation on a phase-only spatial light modulator

    CSIR Research Space (South Africa)

    Dudley, Angela L

    2011-09-01

    Full Text Available amplitude modulation on a phase-only spatial light modulator to implement controlled ring-slit experiments for the generation of nondiffracting speckle fields. The structure of the nondiffracting speckle due to binary and continuous phase modulations...

  10. Speckle reduction in optical coherence tomography using two-step iteration method (Conference Presentation)

    Science.gov (United States)

    Wang, Xianghong; Liu, Xinyu; Wang, Nanshuo; Yu, Xiaojun; Bo, En; Chen, Si; Liu, Linbo

    2017-02-01

    Optical coherence tomography (OCT) provides high resolution and cross-sectional images of biological tissue and is widely used for diagnosis of ocular diseases. However, OCT images suffer from speckle noise, which typically considered as multiplicative noise in nature, reducing the image resolution and contrast. In this study, we propose a two-step iteration (TSI) method to suppress those noises. We first utilize augmented Lagrange method to recover a low-rank OCT image and remove additive Gaussian noise, and then employ the simple and efficient split Bregman method to solve the Total-Variation Denoising model. We validated such proposed method using images of swine, rabbit and human retina. Results demonstrate that our TSI method outperforms the other popular methods in achieving higher peak signal-to-noise ratio (PSNR) and structure similarity (SSIM) while preserving important structural details, such as tiny capillaries and thin layers in retinal OCT images. In addition, the results of our TSI method show clearer boundaries and maintains high image contrast, which facilitates better image interpretations and analyses.

  11. A closer look at dynamic speckles and the use of their fine-structure for object measurements

    DEFF Research Database (Denmark)

    Hanson, Steen Grüner; Iversen, Theis F.Q.; Jakobsen, Michael Linde

    2010-01-01

    The possibility to “dress up” the speckles and thereby providing them with a fine structure will be discussed. As these speckles arise from scattering off solid targets, the dynamics of the speckles and their inherent fine structure might vary, providing information on different aspects of the su...

  12. Selectivity of spatial filtering velocimetry of objective speckles for measuring out-of-plane motion

    DEFF Research Database (Denmark)

    Jakobsen, Michael Linde; Yura, H. T.; Hanson, Steen Grüner

    2012-01-01

    We probe the dynamics of objective laser speckles as the axial distance between the object and the observation plane changes. With the purpose of measuring out-of-plane motion in real time, we apply optical spatial filtering velocimetry to the speckle dynamics. To achieve this, a rotationally...

  13. Parametric optical surface roughness measurement by means of polychromatic speckle autocorrelation

    Science.gov (United States)

    Patzelt, Stefan; Ciossek, Andreas; Lehmann, Peter; Schoene, Armin

    1998-10-01

    A method for determining surface roughness of engineering surfaces that is applicable to in-process measurements under harsh circumstances of industrial production plants (e.g. vibrations, humidity) is introduced. The rough surface is illuminated with polychromatic laser light. The angular distribution of scattered light intensities, i.e. a polychromatic speckle pattern, is the result of an incoherent superposition of monochromatic speckle intensities. The angular dispersion leads to increasing speckle widths with an increasing distance to the optical axis an effect called speckle elongation. This gives rise to a radial structure of the speckle pattern. However, with increasing surface roughness the radial structure vanishes because of a decreasing similarity of the monochromatic speckle patterns of the different wavelengths. The markedness of this effect is analyzed by digital image processing algorithms, e.g. the procedure of polychromatic speckle autocorrelation. The latest approach to an in-process roughness measurement device was made by the use of singlemode fiber-pigtailed laser diodes in order to supply a trichromatic, temporally partially coherent laser beam. A brief introduction to the theoretical background is followed by the presentation of the experimental setup. The image processing algorithms for calculating an optical roughness measure from digitalized speckle patterns are explained, and first results of surface roughness determination are presented.

  14. TV shearography: quantitative measurement of shear-magnitude fields by use of digital speckle photography.

    Science.gov (United States)

    Andersson, A; Krishna Mohan, N; Sjödahl, M; Molin, N E

    2000-06-01

    Digital speckle photography combined with TV shearography is developed for precise measurement of the magnitude of the shear field in a linear shear configuration. As an application the method is implemented to determine the slope-change variations of a three-dimensional object with TV shearography in which the shear magnitude is obtained with the digital speckle photography technique.

  15. A robust detail preserving anisotropic diffusion for speckle reduction in ultrasound images.

    Science.gov (United States)

    Liu, Xiaoming; Liu, Jun; Xu, Xin; Chun, Lei; Tang, Jinshan; Deng, Youping

    2011-12-23

    Speckles in ultrasound imaging affect image quality and can make the post-processing difficult. Speckle reduction technologies have been employed for removing speckles for some time. One of the effective speckle reduction technologies is anisotropic diffusion. Anisotropic diffusion technology can remove the speckles effectively while preserving the edges of the image and thus has drawn great attention from image processing scientists. However, the proposed methods in the past have different disadvantages, such as being sensitive to the number of iterations or low capability of preserving the details of the ultrasound images. Thus a detail preserved anisotropic diffusion speckle reduction with less sensitive to the number of iterations is needed. This paper aims to develop this kind of technologies. In this paper, we propose a robust detail preserving anisotropic diffusion filter (RDPAD) for speckle reduction. In order to get robust diffusion, the proposed method integrates Tukey error norm function into the detail preserving anisotropic diffusion filter (DPAD) developed recently. The proposed method could prohibit over-diffusion and thus is less sensitive to the number of iterations The proposed anisotropic diffusion can preserve the important structure information of the original image while reducing speckles. It is also less sensitive to the number of iterations. Experimental results on real ultrasound images show the effectiveness of the proposed anisotropic diffusion filter.

  16. Effect of speckles on the depth sensitivity of laser Doppler perfusion imaging

    NARCIS (Netherlands)

    Rajan, V.; Varghese, B.; van Leeuwen, T. G.; Steenbergen, W.

    2007-01-01

    A theoretical model is presented and experimentally validated that allows the prediction of the effect of speckles on the depth sensitivity of laser Doppler perfusion imaging. It is shown that the influence of speckles on depth sensitivity is large. In particular the sensitivity to particle motion

  17. Measuring Doppler-like power spectra and dermal perfusion using laser speckle contrast with multiple exposures

    Science.gov (United States)

    Thompson, O. B.; Andrews, M. K.

    2010-02-01

    Laser speckle contrast measurements provide effectively instantaneous maps of dermal perfusion, using easily obtainable hardware, but such maps are qualitative. Clinical applications of these techniques require a good theoretical and experimental foundation of understanding before relating them to a physiologically significant, quantitative perfusion value. We have confirmed that multiple-exposure laser speckle methods produce the same spectral information as laser Doppler measurements when applied to targets such as human tissue with embedded moving scatterers. This confirmation is based on both computer simulation of laser speckle data and experimental measurements on Brownian motion and skin perfusion using a laser Doppler system and a multiple-exposure laser speckle system. The Power Spectral Density (PSD) measurements of the light fluctuations derived using both techniques are equivalent. Dermal perfusion images can therefore be measured in exactly equivalent terms by either laser speckle contrast or more laborious scanning laser Doppler methods. Most analyses relating laser speckle contrast to perfusion depend on assuming a particular temporal autocorrelation function for the light intensity fluctuations in biospeckle. Using multiple-exposure laser speckle allows the autocorrelation function to be measured rather than assumed. Measured autocorrelation functions and their related power spectra for dermal perfusion are presented, including measurements under arterial occlusion to investigate a 'biological zero': the speckle blur relating to the remaining movement of tissue constituents when there is no net blood flow.

  18. Timber tracking

    DEFF Research Database (Denmark)

    Düdder, Boris; Ross, Omry

    2017-01-01

    Managing and verifying forest products in a value chain is often reliant on easily manipulated document or digital tracking methods - Chain of Custody Systems. We aim to create a new means of tracking timber by developing a tamper proof digital system based on Blockchain technology. Blockchain...

  19. Characteristics of track cycling.

    Science.gov (United States)

    Craig, N P; Norton, K I

    2001-01-01

    Track cycling events range from a 200 m flying sprint (lasting 10 to 11 seconds) to the 50 km points race (lasting approximately 1 hour). Unlike road cycling competitions where most racing is undertaken at submaximal power outputs, the shorter track events require the cyclist to tax maximally both the aerobic and anaerobic (oxygen independent) metabolic pathways. Elite track cyclists possess key physical and physiological attributes which are matched to the specific requirements of their events: these cyclists must have the appropriate genetic predisposition which is then maximised through effective training interventions. With advances in technology it is now possible to accurately measure both power supply and demand variables under competitive conditions. This information provides better resolution of factors that are important for training programme design and skill development.

  20. A High-Resolution Multitechniques Approach to Characterize Bio-Organo-Mineral Associations Within Rock Samples: Tracking Biological vs Abiotic Processes? Towards a Better Understanding of the Deep Carbon Cycle.

    Science.gov (United States)

    Pisapia, C.

    2015-12-01

    Among all elements, carbon plays one of the major roles for the sustainability of life on Earth. Past considerations of the carbon cycle have mainly focused on surface processes occurring at the atmosphere, oceans and shallow crustal environments. By contrast, little is known about the Deep Carbon cycle whereas both geochemical and biological processes may induce organic carbon production and/or consumption at depth. Indeed, the nowadays-recognized capability of geochemical processes such as serpentinization to generate abiotic organic compounds as well as the existence of a potentially important intraterrestrial life raises questions about the limit of biotic/abiotic carbon on Earth's deep interior and how it impacts global biogeochemical cycles. It is then mandatory to increase our knowledge on the nature and extent of carbon reservoirs along with their sources, sinks and fluxes in the subsurface. This implies to be able to finely characterize organomineral associations within crustal rocks although it might be hampered by the scarceness and heterogeneous micrometric spatial distribution of organic molecules in natural rocks. We then developed an in situ analytical strategy based on the combination of high-resolution techniques to track organic molecules at the pore level in natural rocks and to determine their biological or abiotic origin. We associated classical high-resolution techniques and synchrotron-based imaging techniques in order to characterize their nature and localization (SEM/TEM, coupled CLSM/Raman spectroscopy, Tof-SIMS) along with their 3D-distribution relatively to mineral phases (S-FTIR, S-DeepUV, XANES, Biphoton microscopy). The effectiveness of this approach to shed light on the speciation and nature of carbon in subsurface environments will be illustrated through the study of (i) subsurface ecosystems and abiotic organic carbon within ultramafic rocks of the oceanic lithosphere as putative analogs for the nature and functioning of primitive

  1. Sensor Alignment by Tracks

    CERN Document Server

    Karimäki, V; Lampen, T; Lindén, T

    2003-01-01

    Good geometrical calibration is essential in the use of high resolution detectors. The individual sensors in the detector have to be calibrated with an accuracy better than the intrinsic resolution, which typically is of the order of 10 um. We present an effective method to perform fine calibration of sensor positions in a detector assembly consisting of a large number of pixel and strip sensors. Up to six geometric parameters, three for location and three for orientation, can be computed for each sensor on a basis of particle trajectories traversing the detector system. The performance of the method is demonstrated with both simulated tracks and tracks reconstructed from experimental data. We also present a brief review of other alignment methods reported in the literature.

  2. Study of drying process of paint by dynamic speckle with B/D pixel counting technique

    Science.gov (United States)

    Balamurugan, R.; Rajarajan, G.

    2017-11-01

    The aim of the work is the assessment of drying process of latex paint by dynamic Laser speckle method. The basic concept of dynamic speckle technique is described. Laser light scattering by water borne sample is a time dependent surface activity. The variation of laser speckle intensity is due to the change of refractive index and the particle movements of the latex paint. A novel method, B/D counting technique to measure the dynamic activity of drying paint using co-occurrence matrix of Time History of Speckle Pattern (THSP) is presented. The result of drying process of latex paint by dynamic laser speckle method is compared with the gravimetric method and agreed well.

  3. Application of dynamic speckle interferometry for diagnosis of metabolism change in cultured cells

    Science.gov (United States)

    Vladimirov, A. P.; Mikhailova, J. A.; Baharev, A. A.; Malygin, A. S.; Novosyolova, I. A.; Yakin, D. I.

    2015-08-01

    Previously, a speckle interferometry technique and a device that allows quantitative evaluation of the metabolic activity of cultured cells were theoretically grounded and successfully tested. A speckle time-averaging technique was proposed to separate and study the processes occurring in cells at various velocities. The objective of the present research was comparing the parameters of speckle dynamics used to evaluate cell metabolism and averaged in areas of various size. Areas inside the speckle image of a cell as well as areas of the image plane with various numbers of cells were averaging areas. Defrosted L-41 cells precipitated on a glass substrate were the target of the research. Time-average value T of digital radiation intensity in the TV camera pixels I~ (1) and the correlation coefficient of two digital images η (2) were used as speckle field change parameters. The digital images corresponded to a single frame area at two time moments.

  4. Optoelectronic imaging of speckle using image processing method

    Science.gov (United States)

    Wang, Jinjiang; Wang, Pengfei

    2018-01-01

    A detailed image processing of laser speckle interferometry is proposed as an example for the course of postgraduate student. Several image processing methods were used together for dealing with optoelectronic imaging system, such as the partial differential equations (PDEs) are used to reduce the effect of noise, the thresholding segmentation also based on heat equation with PDEs, the central line is extracted based on image skeleton, and the branch is removed automatically, the phase level is calculated by spline interpolation method, and the fringe phase can be unwrapped. Finally, the imaging processing method was used to automatically measure the bubble in rubber with negative pressure which could be used in the tire detection.

  5. Body Size Evolution in Insular Speckled Rattlesnakes (Viperidae: Crotalus mitchellii)

    Science.gov (United States)

    Meik, Jesse M.; Lawing, A. Michelle; Pires-daSilva, André

    2010-01-01

    Background Speckled rattlesnakes (Crotalus mitchellii) inhabit multiple islands off the coast of Baja California, Mexico. Two of the 14 known insular populations have been recognized as subspecies based primarily on body size divergence from putative mainland ancestral populations; however, a survey of body size variation from other islands occupied by these snakes has not been previously reported. We examined body size variation between island and mainland speckled rattlesnakes, and the relationship between body size and various island physical variables among 12 island populations. We also examined relative head size among giant, dwarfed, and mainland speckled rattlesnakes to determine whether allometric differences conformed to predictions of gape size (and indirectly body size) evolving in response to shifts in prey size. Methodology/Principal Findings Insular speckled rattlesnakes show considerable variation in body size when compared to mainland source subspecies. In addition to previously known instances of gigantism on Ángel de la Guarda and dwarfism on El Muerto, various degrees of body size decrease have occurred frequently in this taxon, with dwarfed rattlesnakes occurring mostly on small, recently isolated, land-bridge islands. Regression models using the Akaike information criterion (AIC) showed that mean SVL of insular populations was most strongly correlated with island area, suggesting the influence of selection for different body size optima for islands of different size. Allometric differences in head size of giant and dwarf rattlesnakes revealed patterns consistent with shifts to larger and smaller prey, respectively. Conclusions/Significance Our data provide the first example of a clear relationship between body size and island area in a squamate reptile species; among vertebrates this pattern has been previously documented in few insular mammals. This finding suggests that selection for body size is influenced by changes in community dynamics

  6. Body size evolution in insular speckled rattlesnakes (Viperidae: Crotalus mitchellii.

    Directory of Open Access Journals (Sweden)

    Jesse M Meik

    Full Text Available BACKGROUND: Speckled rattlesnakes (Crotalus mitchellii inhabit multiple islands off the coast of Baja California, Mexico. Two of the 14 known insular populations have been recognized as subspecies based primarily on body size divergence from putative mainland ancestral populations; however, a survey of body size variation from other islands occupied by these snakes has not been previously reported. We examined body size variation between island and mainland speckled rattlesnakes, and the relationship between body size and various island physical variables among 12 island populations. We also examined relative head size among giant, dwarfed, and mainland speckled rattlesnakes to determine whether allometric differences conformed to predictions of gape size (and indirectly body size evolving in response to shifts in prey size. METHODOLOGY/PRINCIPAL FINDINGS: Insular speckled rattlesnakes show considerable variation in body size when compared to mainland source subspecies. In addition to previously known instances of gigantism on Angel de la Guarda and dwarfism on El Muerto, various degrees of body size decrease have occurred frequently in this taxon, with dwarfed rattlesnakes occurring mostly on small, recently isolated, land-bridge islands. Regression models using the Akaike information criterion (AIC showed that mean SVL of insular populations was most strongly correlated with island area, suggesting the influence of selection for different body size optima for islands of different size. Allometric differences in head size of giant and dwarf rattlesnakes revealed patterns consistent with shifts to larger and smaller prey, respectively. CONCLUSIONS/SIGNIFICANCE: Our data provide the first example of a clear relationship between body size and island area in a squamate reptile species; among vertebrates this pattern has been previously documented in few insular mammals. This finding suggests that selection for body size is influenced by changes in

  7. Body size evolution in insular speckled rattlesnakes (Viperidae: Crotalus mitchellii).

    Science.gov (United States)

    Meik, Jesse M; Lawing, A Michelle; Pires-daSilva, André

    2010-03-04

    Speckled rattlesnakes (Crotalus mitchellii) inhabit multiple islands off the coast of Baja California, Mexico. Two of the 14 known insular populations have been recognized as subspecies based primarily on body size divergence from putative mainland ancestral populations; however, a survey of body size variation from other islands occupied by these snakes has not been previously reported. We examined body size variation between island and mainland speckled rattlesnakes, and the relationship between body size and various island physical variables among 12 island populations. We also examined relative head size among giant, dwarfed, and mainland speckled rattlesnakes to determine whether allometric differences conformed to predictions of gape size (and indirectly body size) evolving in response to shifts in prey size. Insular speckled rattlesnakes show considerable variation in body size when compared to mainland source subspecies. In addition to previously known instances of gigantism on Angel de la Guarda and dwarfism on El Muerto, various degrees of body size decrease have occurred frequently in this taxon, with dwarfed rattlesnakes occurring mostly on small, recently isolated, land-bridge islands. Regression models using the Akaike information criterion (AIC) showed that mean SVL of insular populations was most strongly correlated with island area, suggesting the influence of selection for different body size optima for islands of different size. Allometric differences in head size of giant and dwarf rattlesnakes revealed patterns consistent with shifts to larger and smaller prey, respectively. Our data provide the first example of a clear relationship between body size and island area in a squamate reptile species; among vertebrates this pattern has been previously documented in few insular mammals. This finding suggests that selection for body size is influenced by changes in community dynamics that are related to graded differences in area over what are

  8. Generalized Method for Sampling Spatially Correlated Heterogeneous Speckled Imagery

    Directory of Open Access Journals (Sweden)

    Alejandro C. Frery

    2001-06-01

    Full Text Available This paper presents a general result for the simulation of correlated heterogeneous targets, which are present in images corrupted by speckle noise. This technique is based on the use of a correlation mask and Gaussian random variables, in order to obtain spatially dependent Gamma deviates. These Gamma random variables, in turn, allow the obtainment of correlated 𝒦 deviates with specified correlation structure. The theoretical properties of the procedure are presented, along with the corresponding algorithm.

  9. Electronics speckle interferometry applications for NDE of spacecraft structural components

    Science.gov (United States)

    Rao, M. V.; Samuel, R.; Ananthan, A.; Dasgupta, S.; Nair, P. S.

    2008-09-01

    The spacecraft components viz., central cylinder, deck plates, solar panel substrates, antenna reflectors are made of aluminium/composite honeycomb sandwich construction. Detection of these defects spacecraft structural components is important to assess the integrity of the spacecraft structure. Electronic Speckle Interferometry (ESI) techniques identify the defects as anomalous regions in the interferometric fringe patterns of the specklegram while the component is suitably stressed to give rise to differential displacement/strain around the defective region. Calibration studies, different phase shifting methods associated with ESI and the development of a prototype Twin Head ESSI System (THESSIS) and its use for the NDE of a typical satellite structural component are presented.

  10. Assessment of left atrial deformation properties by speckle tracking in patients with systolic heart failure

    Directory of Open Access Journals (Sweden)

    Mahmoud K. Ahmed

    2015-09-01

    Conclusion: In patients with SHF, LA function is significantly reduced. Moreover, LA reservoir & booster pump function correlate negatively with heart failure symptoms and positively with LV global strain.

  11. Myocardial Deformation Measured by 3-Dimensional Speckle Tracking in Children and Adolescents With Systemic Arterial Hypertension.

    Science.gov (United States)

    Navarini, Susanne; Bellsham-Revell, Hannah; Chubb, Henry; Gu, Haotian; Sinha, Manish D; Simpson, John M

    2017-12-01

    Systemic arterial hypertension predisposes children to cardiovascular risk in childhood and adult life. Despite extensive study of left ventricular (LV) hypertrophy, detailed 3-dimensional strain analysis of cardiac function in hypertensive children has not been reported. The aim of this study was to evaluate LV mechanics (strain, twist, and torsion) in young patients with hypertension compared with a healthy control group and assess factors associated with functional measurements. Sixty-three patients (26 hypertension and 37 normotensive) were enrolled (mean age, 14.3 and 11.4 years; 54% men and 41% men, respectively). All children underwent clinical evaluation and echocardiographic examination, including 3-dimensional strain. There was no difference in LV volumes and ejection fraction between the groups. Myocardial deformation was significantly reduced in those with hypertension compared with controls. For hypertensive and normotensive groups, respectively, global longitudinal strain was -15.1±2.3 versus -18.5±1.9 ( P hypertensive and normotensive children, but children with hypertension had significantly lower strain indices. Whether reduced strain might predict future cardiovascular risk merits further longitudinal study. © 2017 American Heart Association, Inc.

  12. Global and segmental myocardial deformation by 2D speckle tracking compared to visual assessment.

    Science.gov (United States)

    Anwar, Ashraf M

    2012-12-26

    To examine the feasibility and reliability of measuring global and segmental longitudinal strain (LS) compared to visual assessment of wall motion (WM). Assessment of segmental (17 left ventricular segments) LS using automatic function imaging (AFI) in 55 patients (60.0 ± 8.7 years, 73% male) divided into 2 groups: group I included 35 patients with WM abnormalities and/or impaired ejection fraction and group II included 20 patients with normal WM and ejection fraction. Visual analysis of WM abnormalities was performed using 2-dimensional echocardiography (2DE) and WM score was calculated. Both modalities were analyzed by one expert reader at 2 different sessions. Analysis of 935 left ventricular segments was completed in 94.1% and 96.3% by visual assessment and AFI, respectively. There was a strong positive linear relationship between the WM score and global LS in all patients. Intra-observer agreement for calculation of WM score was excellent for group I patients (kappa: 0.97) and very good for group II patients (kappa: 0.92). Intra-observer agreement for AFI showed excellent agreement with very small mean difference in both group I and II (-0.0 ± 2.3 and -0.0 ± 1.9, respectively). The interpretation of global and segmental LS using AFI is a more feasible and reliable technique for the quantification of myocardial deformation than visual assessment of WM scores.

  13. Modeled and Measured Partially Coherent Illumination Speckle Effects from Sloped Surfaces for Tactical Tracking

    Science.gov (United States)

    2015-03-26

    dimension. The monochronometer output was passed into a photomultiplier tube ( PMT ), chosen for its high dynamic range and SNR, which was in turn connected...window PDF – probability density function PMT – photomultiplier tube, a non-imaging optical detector known for exceptional dynamic range and...Information Operations and Reports (0704–0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202–4302. Respondents should be aware that

  14. Assessment of intraventricular time differences in healthy children using two-dimensional speckle-tracking echocardiography

    NARCIS (Netherlands)

    Klitsie, Liselotte M.; Roest, Arno A. W.; van der Hulst, Annelies E.; Stijnen, Theo; Blom, Nico A.; ten Harkel, Arend D. J.

    2013-01-01

    Parameters describing intraventricular time differences are increasingly assessed in both adults and children. However, to appreciate the implications of these parameters in children, knowledge of the applicability of adult techniques in children is essential. Hence, the aim of this study was to

  15. Comparison of left ventricular mechanics in runners versus bodybuilders using speckle tracking echocardiography

    OpenAIRE

    Szauder, Ipoly; Kov?cs, Attila; Pavlik, G?bor

    2015-01-01

    Background Athlete?s heart is a common definition for a broad spectrum of adaptations induced by intense exercise. We intended to compare left ventricular (LV) mechanics in two sports disciplines with different exercise nature: marathon runners (endurance) and bodybuilders (power). Methods 24 marathon or ultramarathon runners (R), 14 bodybuilders (B) and 15 healthy, sedentary male volunteers (N) were investigated. Beyond standard echocardiographic protocol, parasternal short-axis and apical r...

  16. Predicting Paroxysmal Atrial Fibrillation in Cerebrovascular Ischemia Using Tissue Doppler Imaging and Speckle Tracking Echocardiography

    DEFF Research Database (Denmark)

    Olsen, Flemming Javier; Jørgensen, Peter Godsk; Møgelvang, Rasmus

    2016-01-01

    BACKGROUND: Often the underlying cause of cerebral ischemia (CI) cannot be found during a routine diagnostic investigation, but paroxysmal atrial fibrillation (PAF) could be the culprit. AIM: The objective of the study is to investigate whether advanced echocardiography improves the diagnostic...

  17. Measurement of three-dimensional deformation using speckle projection method

    Science.gov (United States)

    Zhu, Feipeng; Liu, Wenwen; He, Xiaoyuan

    2008-11-01

    Optical triangulation is a useful method that has been studied and utilized extensively. In optical triangulation, the directions of projection and the observation are different, so the patterns captured by CCD camera include information of the object surface profile. Based on the speckle projection, a measurement system to get the three-dimensional deformation of object is developed. With artificial random speckle projected to the object surface, two images before and after object deformation are recorded, respectively. In order to get the information of the deformation, digital image correlation method (DICM) is adopted. Furthermore, the calibration is introduced in detail, which is the procedure of great importance, because it determines directly the accuracy of measurement. Due to variable feature of the calibration coefficient along the x direction, this paper presents a new method to be competent for the calibration, that's segmented calibration method. Experiment is performed and good agreement is found with the proposed calibration. Dynamic measurement results based on such system are also presented in this paper.

  18. Calibration of a speckle-based compressive sensing receiver

    Science.gov (United States)

    Sefler, George A.; Shaw, T. Justin; Stapleton, Andrew D.; Valley, George C.

    2017-02-01

    Optical speckle in a multimode waveguide has been proposed to perform the function of a compressive sensing (CS) measurement matrix (MM) in a receiver for GHz-band radio frequency (RF) signals. Unlike other devices used for the CS MM, e.g. the digital micromirror device (DMD) used in the single pixel camera, the elements of the speckle MM are not known before use and must be measured and calibrated. In our system, the RF signal is modulated on a repetitively pulsed chirped wavelength laser source, generated from mode-locked laser pulses that have been dispersed in time or from an electrically addressed distributed Bragg reflector laser. Next, the optical beam with RF propagates through a multimode fiber or waveguide, which applies different weights in wavelength (or equivalently time) and space and performs the function of the CS MM. The output of the guide is directed to or imaged on a bank of photodiodes with integration time set to the pulse length of the chirp waveform. The output of each photodiode is digitized by an analog-to-digital converter (ADC), and the data from these ADCs are used to form the CS measurement vector. Accurate recovery of the RF signal from CS measurements depends critically on knowledge of the weights in the MM. Here we present results using a stable wavelength laser source to probe the guide.

  19. Speckle reduction for a laser light sectioning sensor

    Directory of Open Access Journals (Sweden)

    Tutsch Rainer

    2015-01-01

    Full Text Available Automated optical inspection is an important test procedure in electronic circuits assembly. Frequently 3d information is required and laser light sectioning sensors are often applied. However, some effects complicate the reliable automatic detection of the shape of such assemblies and their components. The packages of electronic components often are made of black plastics or ceramics so that the intensity available for the optical detection is quite low, especially in comparison to the surface of the PCBs where the components are mounted on. In addition due to rough surfaces of the components and the coherence length of the laser light speckle structures arise. In the work presented here a piezo actuator is used to oscillate the illuminating laser lines along the direction of the lines. The aim is to reduce the visibility of the speckle structures by averaging while maintaining the geometrical shape of the lines. In addition, image processing methods like segmentation and skeletonization are used to allow the detection of the shape of components and assemblies also if materials with distinct differences in the reflectivity are involved. Investigations include the influence of the parameters amplitude and frequency of the piezo actuator.

  20. Intraoperative multi-exposure speckle imaging of cerebral blood flow.

    Science.gov (United States)

    Richards, Lisa M; Kazmi, Sm Shams; Olin, Katherine E; Waldron, James S; Fox, Douglas J; Dunn, Andrew K

    2017-09-01

    Multiple studies have demonstrated that laser speckle contrast imaging (LSCI) has high potential to be a valuable cerebral blood flow monitoring technique during neurosurgery. However, the quantitative accuracy and sensitivity of LSCI is limited, and highly dependent on the exposure time. An extension to LSCI called multi-exposure speckle imaging (MESI) overcomes these limitations, and was evaluated intraoperatively in patients undergoing brain tumor resection. This clinical study ( n = 8) recorded multiple exposure times from the same cortical tissue area spanning 0.5-20 ms, and evaluated images individually as single-exposure LSCI and jointly using the MESI model. This study demonstrated that the MESI estimates provided the broadest flow sensitivity for sampling the flow magnitude in the human brain, closely followed by the shorter exposure times. Conservation of flow analysis on vascular bifurcations was used to validate physiological accuracy, with highly conserved flow estimates (goodness-of-fit with proper image calibration and acquisition, and was used to monitor blood flow changes after tissue cautery. Results from this study demonstrate that intraoperative MESI can be performed with high quantitative accuracy and sensitivity for cerebral blood flow monitoring.

  1. Real time speckle monitoring to control retinal photocoagulation

    Science.gov (United States)

    Bliedtner, Katharina; Seifert, Eric; Brinkmann, Ralf

    2017-07-01

    Photocoagulation is a treatment modality for several retinal diseases. Intra- and inter-individual variations of the retinal absorption as well as ocular transmission and light scattering makes it impossible to achieve a uniform effective exposure with one set of laser parameters. To guarantee a uniform damage throughout the therapy a real-time control is highly requested. Here, an approach to realize a real-time optical feedback using dynamic speckle analysis in-vivo is presented. A 532 nm continuous wave Nd:YAG laser is used for coagulation. During coagulation, speckle dynamics are monitored by a coherent object illumination using a 633 nm diode laser and analyzed by a CMOS camera with a frame rate up to 1 kHz. An algorithm is presented that can discriminate between different categories of retinal pigment epithelial damage ex-vivo in enucleated porcine eyes and that seems to be robust to noise in-vivo. Tissue changes in rabbits during retinal coagulation could be observed for different lesion strengths. This algorithm can run on a FPGA and is able to calculate a feedback value which is correlated to the thermal and coagulation induced tissue motion and thus the achieved damage.

  2. Dynamic laser speckle analyzed considering inhomogeneities in the biological sample

    Science.gov (United States)

    Braga, Roberto A.; González-Peña, Rolando J.; Viana, Dimitri Campos; Rivera, Fernando Pujaico

    2017-04-01

    Dynamic laser speckle phenomenon allows a contactless and nondestructive way to monitor biological changes that are quantified by second-order statistics applied in the images in time using a secondary matrix known as time history of the speckle pattern (THSP). To avoid being time consuming, the traditional way to build the THSP restricts the data to a line or column. Our hypothesis is that the spatial restriction of the information could compromise the results, particularly when undesirable and unexpected optical inhomogeneities occur, such as in cell culture media. It tested a spatial random approach to collect the points to form a THSP. Cells in a culture medium and in drying paint, representing homogeneous samples in different levels, were tested, and a comparison with the traditional method was carried out. An alternative random selection based on a Gaussian distribution around a desired position was also presented. The results showed that the traditional protocol presented higher variation than the outcomes using the random method. The higher the inhomogeneity of the activity map, the higher the efficiency of the proposed method using random points. The Gaussian distribution proved to be useful when there was a well-defined area to monitor.

  3. Accelerated speckle imaging with the ATST visible broadband imager

    Science.gov (United States)

    Wöger, Friedrich; Ferayorni, Andrew

    2012-09-01

    The Advanced Technology Solar Telescope (ATST), a 4 meter class telescope for observations of the solar atmosphere currently in construction phase, will generate data at rates of the order of 10 TB/day with its state of the art instrumentation. The high-priority ATST Visible Broadband Imager (VBI) instrument alone will create two data streams with a bandwidth of 960 MB/s each. Because of the related data handling issues, these data will be post-processed with speckle interferometry algorithms in near-real time at the telescope using the cost-effective Graphics Processing Unit (GPU) technology that is supported by the ATST Data Handling System. In this contribution, we lay out the VBI-specific approach to its image processing pipeline, put this into the context of the underlying ATST Data Handling System infrastructure, and finally describe the details of how the algorithms were redesigned to exploit data parallelism in the speckle image reconstruction algorithms. An algorithm re-design is often required to efficiently speed up an application using GPU technology; we have chosen NVIDIA's CUDA language as basis for our implementation. We present our preliminary results of the algorithm performance using our test facilities, and base a conservative estimate on the requirements of a full system that could achieve near real-time performance at ATST on these results.

  4. Tracking FEMA

    OpenAIRE

    Leskanic, Tyler; Kays, Kevin; Maier, Emily; Cannon, Seth

    2015-01-01

    The zip archive attached to this project is the compressed TrackingFEMA Git repository. It contains the CMS (RefineryCMS - Rails), processing scripts, as well as visualization sample code. The processing scripts are in a folder called TrackingFEMAProcessing. The visualizations are contained in Visualization. The rest of the rails files are contained within the usual Ruby on Rails file system structure. The finished product is a website visualizing the efforts of disaster response organizat...

  5. Signal-to-noise based local decorrelation compensation for speckle interferometry applications.

    Science.gov (United States)

    Molimard, Jérôme; Cordero, Raul; Vautrin, Alain

    2008-07-01

    Speckle-based interferometric techniques allow assessing the whole-field deformation induced on a specimen due to the application of load. These high sensitivity optical techniques yield fringe images generated by subtracting speckle patterns captured while the specimen undergoes deformation. The quality of the fringes, and in turn the accuracy of the deformation measurements, strongly depends on the speckle correlation. Specimen rigid body motion leads to speckle decorrelation that, in general, cannot be effectively counteracted by applying a global translation to the involved speckle patterns. In this paper, we propose a recorrelation procedure based on the application of locally evaluated translations. The proposed procedure implies dividing the field into several regions, applying a local translation, and calculating, in every region, the signal-to-noise ratio (SNR). Since the latter is a correlation indicator (the noise increases with the decorrelation) we argue that the proper translation is that which maximizes the locally evaluated SNR. The search of the proper local translations is, of course, an interactive process that can be facilitated by using a SNR optimization algorithm. The performance of the proposed recorrelation procedure was tested on two examples. First, the SNR optimization algorithm was applied to fringe images obtained by subtracting simulated speckle patterns. Next, it was applied to fringe images obtained by using a shearography optical setup from a specimen subjected to mechanical deformation. Our results show that the proposed SNR optimization method can significantly improve the reliability of measurements performed by using speckle-based techniques.

  6. Additive-subtractive phase-modulated speckle interferometry: Fringe visibility under partial decorrelation

    Science.gov (United States)

    Krishnaswamy, Sridhar; Pouet, Bruno F.; Chatters, Tom C.

    1997-02-01

    Additive-subtractive phase modulated speckle interferometry (ASPMSI) is a technique that minimizes the susceptibility of speckle methods to environmental noise while providing fringes of good visibility. The method requires the acquisition of two consecutive video frames of additive-speckle images of the same two deformed states of an object at a rapid enough rate such that ambient noise is not a problem. The additive-speckle images as expected are of very poor visibility due to the presence of the self-interference term. An interframe phase-modulation is introduced and the two additive-speckle images are digitally subtracted to improve the fringe visibility by removing the self-interference term. The ASPM-SI method works with in-plane and out-of-plane deformation sensitive ESPI as well as with displacement-gradient sensitive speckle-shearing interferometry. It is shown that the ASPM-SI scheme has higher visibility than conventional additive-SI and performs consistently better than subtractive-SI schemes in the presence of partial interframe speckle decorrelating optical noise. Furthermore, it is shown that the fringe visibility of the out-of-plane displacement sensitive interferometer which uses a protected reference beam separate from the object beam can be made to be essentially unity even at complete interframe decorrelation.

  7. Study of Track Reconstruction for DAMPE

    Science.gov (United States)

    Lu, Tong-suo; Lei, Shi-jun; Zang, Jing-jing; Chang, Jin; Wu, Jian

    2017-07-01

    The Dark Matter Particle Explorer (DAMPE) is aimed to study the existence and distribution of dark matter via the observation of high-energy particles in space with a large energy bandwidth, high energy resolution, and high spatial resolution. The track reconstruction is to restore the positions and angles of the incident particles using the multiple observations of different channels at different positions, and its accuracy determines the angular resolution of the explorer. The track reconstruction is mainly based on the observations of two sub-detectors, namely, the Silicon Tracker (STK) and the BGO (Bi4Ge3O12) calorimeter. In accordance with the design and structure of the two sub-detectors, and using the data collected during the beam tests and ground tests of cosmic rays, we discuss in detail the method of track reconstruction for the DAMPE, which includes mainly three basic procedures: the selection of track hits, the fitting of track hits, and the judgement of the optimal track. Since an energetic particle most probably leaves multiple hits in different layers of the STK and BGO crystals, we first provide a method to obtain a rough track in the BGO calorimeter by the centroid method, and hereby to constrain the track hits in the STK. Then for the selected one group of possible track hits in the STK, we apply two different algorithms, the Kalman filter and the least square linear fitting, to fit these track hits. The consistency of the results obtained independently via the two algorithms confirms the validity of our track reconstruction results. Finally, several criteria for picking out the most possible track among all the tracks found in the reconstruction by combining the results of the BGO calorimeter and STK are discussed. Using the track reconstruction method proposed in this article and the beam test data, we confirm that the angular resolution of the DAMPE satisfies its design requirement.

  8. COCOA: tracking in aerial imagery

    Science.gov (United States)

    Ali, Saad; Shah, Mubarak

    2006-05-01

    Unmanned Aerial Vehicles (UAVs) are becoming a core intelligence asset for reconnaissance, surveillance and target tracking in urban and battlefield settings. In order to achieve the goal of automated tracking of objects in UAV videos we have developed a system called COCOA. It processes the video stream through number of stages. At first stage platform motion compensation is performed. Moving object detection is performed to detect the regions of interest from which object contours are extracted by performing a level set based segmentation. Finally blob based tracking is performed for each detected object. Global tracks are generated which are used for higher level processing. COCOA is customizable to different sensor resolutions and is capable of tracking targets as small as 100 pixels. It works seamlessly for both visible and thermal imaging modes. The system is implemented in Matlab and works in a batch mode.

  9. Real-time line-scanning reflectance confocal endoscope to enhance sectioning and reduce speckle for intraoral imaging

    Science.gov (United States)

    Glazowski, Christopher; Abeytunge, Sanjeewa; Rajadhyaksha, Milind

    2012-02-01

    The line-scanning confocal microscope is simpler than a point-scanning confocal microscope and allows for a smaller and lower cost footprint, making it attractive for endoscopic clinical use. The optical configuration affects image fidelity. Here, we present a benchtop version of an endoscopic line-scanning confocal microscope for intraoral imaging, with a divided pupil and optimal detection configuration (magnification, pixel-to-resolution ratio) to enhance image fidelity. Improved sectioning performance and reduction of "speckle" noise are demonstrated. A topology for use of a deformable MEMs mirror-based optical axial focus control for imaging in depth is presented. Preliminary images of human oral mucosa in vivo demonstrate feasibility for clinical application.

  10. Synchronized renal blood flow dynamics mapped with wavelet analysis of laser speckle flowmetry data

    DEFF Research Database (Denmark)

    Brazhe, Alexey R; Marsh, Donald J; von Holstein-Rathlou, Niels-Henrik

    2014-01-01

    Full-field laser speckle microscopy provides real-time imaging of superficial blood flow rate. Here we apply continuous wavelet transform to time series of speckle-estimated blood flow from each pixel of the images to map synchronous patterns in instantaneous frequency and phase on the surface...... of rat kidneys. The regulatory mechanism in the renal microcirculation generates oscillations in arterial blood flow at several characteristic frequencies. Our approach to laser speckle image processing allows detection of frequency and phase entrainments, visualization of their patterns, and estimation...

  11. A dynamic monitoring approach for the surface morphology evolution measurement of plasma facing components by means of speckle interferometry

    Science.gov (United States)

    Wang, Hongbei; Cui, Xiaoqian; Feng, Chunlei; Li, Yuanbo; Zhao, Mengge; Luo, Guangnan; Ding, Hongbin

    2017-11-01

    Plasma Facing Components (PFCs) in a magnetically confined fusion plasma device will be exposed to high heat load and particle fluxes, and it would cause PFCs' surface morphology to change due to material erosion and redeposition from plasma wall interactions. The state of PFCs' surface condition will seriously affect the performance of long-pulse or steady state plasma discharge in a tokamak; it will even constitute an enormous threat to the operation and the safety of fusion plasma devices. The PFCs' surface morphology evolution measurement could provide important information about PFCs' real-time status or damage situation and it would help to a better understanding of the plasma wall interaction process and mechanism. Meanwhile through monitoring the distribution of dust deposition in a tokamak and providing an upper limit on the amount of loose dust, the PFCs' surface morphology measurement could indirectly contribute to keep fusion operational limits and fusion device safety. Aiming at in situ dynamic monitoring PFCs' surface morphology evolution, a laboratory experimental platform DUT-SIEP (Dalian University of Technology-speckle interferometry experimental platform) based on the speckle interferometry technique has been constructed at Dalian University of Technology (DUT) in China. With directional specific designing and focusing on the real detection condition of EAST (Experimental Advanced Superconducting Tokamak), the DUT-SIEP could realize a variable measurement range, widely increased from 0.1 μm to 300 μm, with high spatial resolution (<1 mm) and ultra-high time resolution (<2 s for EAST measuring conditions). Three main components of the DUT-SIEP are all integrated and synchronized by a time schedule control and data acquisition terminal and coupled with a three-dimensional phase unwrapping algorithm, the surface morphology information of target samples can be obtained and reconstructed in real-time. A local surface morphology of the real divertor

  12. Nephron blood flow dynamics measured by laser speckle contrast imaging

    DEFF Research Database (Denmark)

    von Holstein-Rathlou, Niels-Henrik; Sosnovtseva, Olga V; Pavlov, Alexey N

    2011-01-01

    Tubuloglomerular feedback (TGF) has an important role in autoregulation of renal blood flow and glomerular filtration rate (GFR). Because of the characteristics of signal transmission in the feedback loop, the TGF undergoes self-sustained oscillations in single-nephron blood flow, GFR, and tubular...... pressure and flow. Nephrons interact by exchanging electrical signals conducted electrotonically through cells of the vascular wall, leading to synchronization of the TGF-mediated oscillations. Experimental studies of these interactions have been limited to observations on two or at most three nephrons...... simultaneously. The interacting nephron fields are likely to be more extensive. We have turned to laser speckle contrast imaging to measure the blood flow dynamics of 50-100 nephrons simultaneously on the renal surface of anesthetized rats. We report the application of this method and describe analytic...

  13. Analysis of eroded bovine teeth through laser speckle imaging

    Science.gov (United States)

    Koshoji, Nelson H.; Bussadori, Sandra K.; Bortoletto, Carolina C.; Oliveira, Marcelo T.; Prates, Renato A.; Deana, Alessandro M.

    2015-02-01

    Dental erosion is a non-carious lesion that causes progressive tooth wear of structure through chemical processes that do not involve bacterial action. Its origin is related to eating habits or systemic diseases involving tooth contact with substances that pose a very low pH. This work demonstrates a new methodology to quantify the erosion by coherent light scattering of tooth surface. This technique shows a correlation between acid etch duration and laser speckle contrast map (LASCA). The experimental groups presented a relative contrast between eroded and sound tissue of 17.8(45)%, 23.4 (68)% 39.2 (40)% and 44.3 (30)%, for 10 min, 20 min, 30 min and 40 min of acid etching, respectively.

  14. Pulsed lasers in speckle photography: error owing to pulse width.

    Science.gov (United States)

    Joenathan, C; Blair, S M; Ganesan, A R

    1993-01-10

    The effect of the pulse width of a pulsed laser in the studies of speckle velocimetry and transient vibration analysis is discussed. Because of the motion of the object during an exposure, a sine function is obtained by using the pointwise filtering method. This function modulates the halo along with the Young's fringes. It is shown that for high object velocities the sinc function modifies the halo distribution; as a result, the error in calculating the fringe position increases. An aperture geometry for which the autocorrelation halo is made constant in certain regions is proposed in which the intensity variation in this region is the result of the modulating sinc function only. A closed-form solution for the shift in the position of the fringes in this region is obtained. Experimental results of the simulation are presented.

  15. Dynamic speckle analysis with smoothed intensity-based activity maps

    Science.gov (United States)

    Stoykova, Elena; Berberova, Natalia; Kim, Youngmin; Nazarova, Dimana; Ivanov, Branimir; Gotchev, Atanas; Hong, Jisoo; Kang, Hoonjong

    2017-06-01

    Pointwise intensity-based algorithms are the most popular algorithms in dynamic laser speckle measurement of physical or biological activity. The output of this measurement is a two-dimensional map which qualitatively separates regions of higher or lower activity. In the paper, we have proposed filtering of activity maps to enhance visualization and to enable quantitative determination of activity time scales. As a first step, we have proved that the severe spatial fluctuations within the map resemble a signal-dependent noise. As a second step, we have illustrated implementation of the proposed idea by applying filters to non-normalized and normalized activity estimates derived from synthetic and experimental data. Statistical behavior of the estimates has been analyzed to choose the filter parameters, and substantial narrowing of the probability density functions of the estimates has been achieved after the filtering. The filtered maps exhibit an improved contrast and allowed for quantitative description of activity.

  16. Speckle reduction via higher order total variation approach.

    Science.gov (United States)

    Wensen Feng; Hong Lei; Yang Gao

    2014-04-01

    Multiplicative noise (also known as speckle) reduction is a prerequisite for many image-processing tasks in coherent imaging systems, such as the synthetic aperture radar. One approach extensively used in this area is based on total variation (TV) regularization, which can recover significantly sharp edges of an image, but suffers from the staircase-like artifacts. In order to overcome the undesirable deficiency, we propose two novel models for removing multiplicative noise based on total generalized variation (TGV) penalty. The TGV regularization has been mathematically proven to be able to eliminate the staircasing artifacts by being aware of higher order smoothness. Furthermore, an efficient algorithm is developed for solving the TGV-based optimization problems. Numerical experiments demonstrate that our proposed methods achieve state-of-the-art results, both visually and quantitatively. In particular, when the image has some higher order smoothness, our methods outperform the TV-based algorithms.

  17. Speckle Noise Reduction via Nonconvex High Total Variation Approach

    Directory of Open Access Journals (Sweden)

    Yulian Wu

    2015-01-01

    Full Text Available We address the problem of speckle noise removal. The classical total variation is extensively used in this field to solve such problem, but this method suffers from the staircase-like artifacts and the loss of image details. In order to resolve these problems, a nonconvex total generalized variation (TGV regularization is used to preserve both edges and details of the images. The TGV regularization which is able to remove the staircase effect has strong theoretical guarantee by means of its high order smooth feature. Our method combines the merits of both the TGV method and the nonconvex variational method and avoids their main drawbacks. Furthermore, we develop an efficient algorithm for solving the nonconvex TGV-based optimization problem. We experimentally demonstrate the excellent performance of the technique, both visually and quantitatively.

  18. Speckle patterns during the spreading of lung surfactant

    Science.gov (United States)

    Llovera-González, Juan J.; Moreno-Yeras, Alfredo B.; Martínez-Muñoz, Diana M.; Ferreira, Marcia Zotti Justo; Shin Nishitani, Wagner; Almeida, Alexandre Barros; Alencar, Adriano M.; Muramatsu, Mikiya; Serra-Toledo, Rolando L.

    2013-11-01

    Pulmonary surfactant is a very important product in the medical treatment of the syndrome of insufficiency respiratory in neonates. The synthesis of this surfactant in labs need to optimize the rate of spreading in the alveolar interstitial liquid obtaining a monolayer of the phospholipids membrane base capable to maintains several of the dynamical properties of the respiratory system during breathing. The recover of theses mechanical properties has to be archived using the minimal quantities of product and with the optimal proteins composition (SP-B in special). In this paper we show our results of obtaining and process speckle pattern images of the spreading of phospholipids membrane composed the matrix of this product (DPPC) when physiologic interstitial liquid are presented.

  19. Evaluation and correction for optical scattering variations in laser speckle rheology of biological fluids.

    Science.gov (United States)

    Hajjarian, Zeinab; Nadkarni, Seemantini K

    2013-01-01

    Biological fluids fulfill key functionalities such as hydrating, protecting, and nourishing cells and tissues in various organ systems. They are capable of these versatile tasks owing to their distinct structural and viscoelastic properties. Characterizing the viscoelastic properties of bio-fluids is of pivotal importance for monitoring the development of certain pathologies as well as engineering synthetic replacements. Laser Speckle Rheology (LSR) is a novel optical technology that enables mechanical evaluation of tissue. In LSR, a coherent laser beam illuminates the tissue and temporal speckle intensity fluctuations are analyzed to evaluate mechanical properties. The rate of temporal speckle fluctuations is, however, influenced by both optical and mechanical properties of tissue. Therefore, in this paper, we develop and validate an approach to estimate and compensate for the contributions of light scattering to speckle dynamics and demonstrate the capability of LSR for the accurate extraction of viscoelastic moduli in phantom samples and biological fluids of varying optical and mechanical properties.

  20. Speckle dynamics for dual-beam optical illumination of a rotating structure

    DEFF Research Database (Denmark)

    Jakobsen, Michael Linde; Yura, Harold; Hanson, Steen Grüner

    2009-01-01

    An out-of-plane rotating object is illuminated with two spatially separated coherent beams, giving rise to fully developed speckles, which will translate and gradually decorrelate in the observation plane, located in the far field. The speckle pattern is a compound structure, consisting of random...... speckles modulated by a smaller and repetitive structure. Generally, these two components of the compound speckle structure will move as rigid structures with individual velocities determined by the characteristics of the two illuminating beams. Closed-form analytical expressions are found for the space......- and time-lagged covariance of irradiance and the corresponding power spectrum for the two spatially separated illuminating beams. The present analysis is valid for propagation through an arbitrary ABCD system, though the focus for the experimental evaluation is far-field observations using an optical...

  1. Clipped speckle autocorrelation metric for spot size characterization of focused beam on a diffuse target

    National Research Council Canada - National Science Library

    Li, Yuanyang; Guo, Jin; Liu, Lisheng; Wang, Tingfeng; Tang, Wei; Jiang, Zhenhua

    2015-01-01

    The clipped speckle autocorrelation (CSA) metric is proposed for estimating the laser beam energy concentration on a remote diffuse target in a laser beam projection system with feedback information...

  2. An Electronic Speckle Pattern Interferometry System for the Study of Mistuned Bladed Disks

    National Research Council Canada - National Science Library

    Pierre, Christophe

    2000-01-01

    .... An Electronic Speckle Pattern Interferometry system provides real-time, full-field imaging of the vibration of a test specimen, while a Single Point Laser Vibrometer, mounted on a two-stage linear...

  3. Simulations of multi-contrast x-ray imaging using near-field speckles

    Energy Technology Data Exchange (ETDEWEB)

    Zdora, Marie-Christine [Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748 Garching (Germany); Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, United Kingdom and Department of Physics & Astronomy, University College London, London, WC1E 6BT (United Kingdom); Thibault, Pierre [Department of Physics & Astronomy, University College London, London, WC1E 6BT (United Kingdom); Herzen, Julia; Pfeiffer, Franz [Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748 Garching (Germany); Zanette, Irene [Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE (United Kingdom); Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748 Garching (Germany)

    2016-01-28

    X-ray dark-field and phase-contrast imaging using near-field speckles is a novel technique that overcomes limitations inherent in conventional absorption x-ray imaging, i.e. poor contrast for features with similar density. Speckle-based imaging yields a wealth of information with a simple setup tolerant to polychromatic and divergent beams, and simple data acquisition and analysis procedures. Here, we present a simulation software used to model the image formation with the speckle-based technique, and we compare simulated results on a phantom sample with experimental synchrotron data. Thorough simulation of a speckle-based imaging experiment will help for better understanding and optimising the technique itself.

  4. Evaluation and correction for optical scattering variations in laser speckle rheology of biological fluids.

    Directory of Open Access Journals (Sweden)

    Zeinab Hajjarian

    Full Text Available Biological fluids fulfill key functionalities such as hydrating, protecting, and nourishing cells and tissues in various organ systems. They are capable of these versatile tasks owing to their distinct structural and viscoelastic properties. Characterizing the viscoelastic properties of bio-fluids is of pivotal importance for monitoring the development of certain pathologies as well as engineering synthetic replacements. Laser Speckle Rheology (LSR is a novel optical technology that enables mechanical evaluation of tissue. In LSR, a coherent laser beam illuminates the tissue and temporal speckle intensity fluctuations are analyzed to evaluate mechanical properties. The rate of temporal speckle fluctuations is, however, influenced by both optical and mechanical properties of tissue. Therefore, in this paper, we develop and validate an approach to estimate and compensate for the contributions of light scattering to speckle dynamics and demonstrate the capability of LSR for the accurate extraction of viscoelastic moduli in phantom samples and biological fluids of varying optical and mechanical properties.

  5. 3D shape measurement using deterministic phase retrieval and a partially developed speckle field

    DEFF Research Database (Denmark)

    Almoro, Percival F.; Waller, Laura; Agour, Mostafa

    2012-01-01

    Fourier domain. The local variations of the recorded speckle patterns and the defocus distance approximate the axial intensity derivative which, in turn, is required to recover the wavefront phase via the transport of intensity equation (TIE). The SLM setup reduces the speckle recording time and the TIE......For deterministic phase retrieval, the problem of insignificant axial intensity variations upon defocus of a smooth object wavefront is addressed. Our proposed solution is based on the use of a phase diffuser facilitating the formation of a partially-developed speckle field (i.e., a field with both...... allows direct (i.e., non-iterative) calculation of the phase. The pre-requisite partially-developed speckle field in our technique facilitates high image contrast and significant axial intensity variation. Wavefront reconstruction for the 3D refractive test object used demonstrates the effectiveness...

  6. Tracking Information

    NARCIS (Netherlands)

    van Benthem, J.; Bimbó, K.

    2016-01-01

    Depending on a relevant task at hand, information can be represented at different levels, less or more detailed, each supporting its own appropriate logical languages. We discuss a few of these levels and their connections, and investigate when and how information growth at one level can be tracked

  7. Higher?order oligomerization promotes localization of SPOP to liquid nuclear speckles

    OpenAIRE

    Marzahn, Melissa R.; Marada, Suresh; Lee, Jihun; Nourse, Amanda; Kenrick, Sophia; Zhao, Huaying; Ben?Nissan, Gili; Kolaitis, Regina?Maria; Peters, Jennifer L.; Pounds, Stanley; Errington, Wesley J; Priv?, Gilbert G; Taylor, J Paul; Sharon, Michal; Schuck, Peter

    2016-01-01

    Abstract Membrane?less organelles in cells are large, dynamic protein/protein or protein/RNA assemblies that have been reported in some cases to have liquid droplet properties. However, the molecular interactions underlying the recruitment of components are not well understood. Herein, we study how the ability to form higher?order assemblies influences the recruitment of the speckle?type POZ protein (SPOP) to nuclear speckles. SPOP, a cullin?3?RING ubiquitin ligase (CRL3) substrate adaptor, s...

  8. Single-shot speckle reduction in numerical reconstruction of digitally recorded holograms.

    Science.gov (United States)

    Hincapie, Diego; Herrera-Ramírez, Jorge; Garcia-Sucerquia, Jorge

    2015-04-15

    A single-shot method to reduce the speckle noise in the numerical reconstructions of electronically recorded holograms is presented. A recorded hologram with the dimensions N×M is split into S=T×T sub-holograms. The uncorrelated superposition of the individually reconstructed sub-holograms leads to an image with the speckle noise reduced proportionally to the 1/S law. The experimental results are presented to support the proposed methodology.

  9. Speckle-based three-dimensional velocity measurement using spatial filtering velocimetry

    DEFF Research Database (Denmark)

    Iversen, Theis Faber Quist; Jakobsen, Michael Linde; Hanson, Steen Grüner

    2011-01-01

    We present an optical method for measuring the real-time three-dimensional (3D) translational velocity of a diffusely scattering rigid object observed through an imaging system. The method is based on a combination of the motion of random speckle patterns and regular fringe patterns. The speckle...... spatial filters designed to measure the three components of the object’s translational velocity. Furthermore, experimental data are presented that demonstrate full 3D velocity measurement....

  10. Single-axis combined shearography and digital speckle photography instrument for full surface strain characterization

    OpenAIRE

    Groves, Roger M.; Fu, S.; James, Stephen W.; Tatam, Ralph P.

    2005-01-01

    Full characterization of the surface strain requires the measurement of six displacement gradient components of the surface strain tensor. The out-of-plane displacement gradient component may be directly measured using the full-field speckle interferometry technique of shearography, but to fully characterize the surface strain using shearography, a minimum of three illumination, or viewing, directions are required. The image processing technique of digital speckle photograph...

  11. Deformable Models for Eye Tracking

    DEFF Research Database (Denmark)

    Vester-Christensen, Martin; Leimberg, Denis; Ersbøll, Bjarne Kjær

    2005-01-01

    A deformable template method for eye tracking on full face images is presented. The strengths of the method are that it is fast and retains accuracy independently of the resolution. We compare the me\\$\\backslash\\$-thod with a state of the art active contour approach, showing that the heuristic...

  12. Speckle-correlation imaging through highly scattering turbid media with LED illumination

    Science.gov (United States)

    Shao, Xiaopeng; Dai, Weijia; Wu, Tengfei; Li, Huijuan; Wang, Lin

    2015-05-01

    We address an optical imaging method that allows imaging, which owing to the "memory-effect" for speckle correlations, through highly scattering turbid media with "Error Reduction - Hybid Input Ouput (ER-HIO)" algorithm. When light propagates through the opaque materials, such as white paint, paper or biological tissues, it will be scattered away due to the inhomogeneity of the refractive index. Multiple scattering of light in highly scattering media forms speckle field, which will greatly reduce the imaging depth and degrade the imaging quality. Some methods have been developed to solve this problem in recent years, including wavefront modulation method (WMM), transmission matrix method (TMM) and speckle correlations method (SCM). A novel approach is proposed to image through a highly scattering turbid medium, which combines speckle correlations method (SCM) with phase retrieval algorithm (PRA). Here, we show that, owing to the "optical memory effect" for speckle correlations, a single frame image of the speckle field, captured with a high performance detector, encodes sufficient information to image through highly scattering turbid media. Theoretical and experimental results show that, neither the light source, nor wave-front shaping is required in this method, and that the imaging can be easily realized here using just a simple optical system with the help of optical memory effect. Our method does not require coherent light source, which can be achieved with LED illumination, unlike previous approaches, and therefore is potentially suitable for more and more areas. Consequently, it will be beneficial to achieve imaging in currently inaccessible scenarios.

  13. Tracking Porters

    DEFF Research Database (Denmark)

    Bruun, Maja Hojer; Krause-Jensen, Jakob; Saltofte, Margit

    2015-01-01

    Anthropology attempts to gain insight into people's experiential life-worlds through long-term fieldwork. The quality of anthropological knowledge production, however, does not depend solely on the duration of the stay in the field, but also on a particular way of seeing social situations. The an...... the students followed the work of a group of porters. Drawing on anthropological concepts and research strategies the students gained crucial insights about the potential effects of using tracking technologies in the hospital....

  14. Magnetic eye tracking in mice.

    Science.gov (United States)

    Payne, Hannah L; Raymond, Jennifer L

    2017-09-05

    Eye movements provide insights about a wide range of brain functions, from sensorimotor integration to cognition; hence, the measurement of eye movements is an important tool in neuroscience research. We describe a method, based on magnetic sensing, for measuring eye movements in head-fixed and freely moving mice. A small magnet was surgically implanted on the eye, and changes in the magnet angle as the eye rotated were detected by a magnetic field sensor. Systematic testing demonstrated high resolution measurements of eye position of eye tracking offers several advantages over the well-established eye coil and video-oculography methods. Most notably, it provides the first method for reliable, high-resolution measurement of eye movements in freely moving mice, revealing increased eye movements and altered binocular coordination compared to head-fixed mice. Overall, magnetic eye tracking provides a lightweight, inexpensive, easily implemented, and high-resolution method suitable for a wide range of applications.

  15. Selectivity and balance of spatial filtering velocimetry of objective speckles for measuring out-of-plane motion

    DEFF Research Database (Denmark)

    Jakobsen, Michael Linde; Yura, Hal T.; Hanson, Steen Grüner

    2015-01-01

    symmetric spatial filter is designed. The spatial filter converts the speckle dynamics into a photocurrent with a quasi-sinusoidal response to the out-of-plane motion. Our contribution presents the technology, discusses the selectivity of the spatial filter and proposes two solutions to balance phase......-stepped photocurrents. Specifically, we discuss how the selectivity of the spatial filter with regard to radial speckle motion is influenced by a concurrent in-plane speckle motion. The spatial filter is emulated with a CCD camera and is tested on speckle acquisitions obtained from a controlled setup. Experiments...

  16. Alignment of the LHCb tracking system

    CERN Document Server

    Märki, Raphael

    2011-01-01

    The LHCb experiment at the LHC is dedicated to precision measurements of $CP$-violation and rare decays in the $b$ and $c$ sectors. The experiment features a tracking system consisting of silicon strip detectors and straw tube drift chambers up- and downstream of the magnet to precisely measure the vertex position and the momentum resolution of the particles travelling through the detector. An important ingredient to the track parameter resolution is the spatial alignment of the tracking system on which we report here.

  17. EVALUATION OF FILTERS FOR ENVISAT ASAR SPECKLE SUPPRESSION IN PASTURE AREA

    Directory of Open Access Journals (Sweden)

    X. Wang

    2012-07-01

    Full Text Available In order to quantify real time pasture biomass from SAR image, regression model between ground measurements of biomass and ENVISAT ASAR backscattering coefficient should be built up. An important prerequisite of valid and accurate regression model is accurate grass backscattering coefficient which, however, cannot be obtained when there is speckle. Speckle noise is the best known problem of SAR images because of the coherent nature of radar illumination imaging system. This study aims to choose better adaptive filter from NEST software to reduce speckle noise in homogeneous pasture area, with little regard to linear feature (e.g. edge between pasture and forest or point feature (e.g. pond, tree preservation. This paper presents the speckle suppression result of ENVISAT ASAR VV/VH images in pasture of Western Australia (WA using four built-in adaptive filters of the NEST software: Frost, Gamma Map, Lee, and Refined Lee filter. Two indices are usually used for evaluation of speckle suppression ability: ENL (Equivalent Number of Looks and SSI (Speckle Suppression Index. These two, however, are not reliable because sometimes they overestimate mean value. Therefore, apart from ENL and SSI, the authors also used a new index SMPI (Speckle Suppression and Mean Preservation Index. It was found that, Lee filter with window size 7×7 and Frost filter (damping factor = 2 with window size 5×5 gave the best performance for VV and VH polarization, respectively. The filtering, together with radiometric calibration and terrain correction, paves the way to extraction of accurate backscattering coefficient of grass in homogeneous pasture area in WA.

  18. CDKL5 influences RNA splicing activity by its association to the nuclear speckle molecular machinery.

    Science.gov (United States)

    Ricciardi, Sara; Kilstrup-Nielsen, Charlotte; Bienvenu, Thierry; Jacquette, Aurélia; Landsberger, Nicoletta; Broccoli, Vania

    2009-12-01

    Mutations in the human X-linked cyclin-dependent kinase-like 5 (CDKL5) gene have been shown to cause severe neurodevelopmental disorders including infantile spasms, encephalopathy, West-syndrome and an early-onset variant of Rett syndrome. CDKL5 is a serine/threonine kinase whose involvement in Rett syndrome can be inferred by its ability to directly bind and mediate phosphorylation of MeCP2. However, it remains to be elucidated how CDKL5 exerts its function. Here, we report that CDKL5 localizes to specific nuclear foci referred to as nuclear speckles in both cell lines and tissues. These sub-nuclear structures are traditionally considered as storage/modification sites of pre-mRNA splicing factors. Interestingly, we provide evidence that CDKL5 regulates the dynamic behaviour of nuclear speckles. Indeed, CDKL5 overexpression leads to nuclear speckle disassembly, and this event is strictly dependent on its kinase activity. Conversely, its down-regulation affects nuclear speckle morphology leading to abnormally large and uneven speckles. Similar results were obtained for primary adult fibroblasts isolated from CDKL5-mutated patients. Altogether, these findings indicate that CDKL5 controls nuclear speckle morphology probably by regulating the phosphorylation state of splicing regulatory proteins. Nuclear speckles are dynamic sites that can continuously supply splicing factors to active transcription sites, where splicing occurs. Notably, we proved that CDKL5 influences alternative splicing, at least as proved in heterologous minigene assays. In conclusion, we provide evidence that CDKL5 is involved indirectly in pre-mRNA processing, by controlling splicing factor dynamics. These findings identify a biological process whose disregulation might affect neuronal maturation and activity in CDKL5-related disorders.

  19. Fuzzy Logic Particle Tracking

    Science.gov (United States)

    2005-01-01

    correlation displacement peak even when it is not the maximum peak, hence maximizing the information recovery from the correlation operation, maintaining the number of independent measurements, and minimizing the number of spurious velocity vectors. Correlation peaks are correctly identified in both high and low seed density cases. The correlation velocity vector map can then be used as a guide for the particle-tracking operation. Again fuzzy logic techniques are used, this time to identify the correct particle image pairings between exposures to determine particle displacements, and thus the velocity. Combining these two techniques makes use of the higher spatial resolution available from the particle tracking. Particle tracking alone may not be possible in the high seed density images typically required for achieving good results from the correlation technique. This two-staged velocimetric technique can measure particle velocities with high spatial resolution over a broad range of seeding densities.

  20. Demonstration of a Speckle Nulling Algorithm and Kalman Filter Estimator with a Fiber Injection Unit for Observing Exoplanets with High-dispersion Coronagraphy

    Science.gov (United States)

    Xin, Yeyuan; Klimovich, Nikita; Mawet, Dimitri; Ruane, Garreth; Delorme, Jacques; Jovanovic, Nemanja; Llop Sayson, Jorge

    2018-01-01

    High-dispersion coronagraphy (HDC) combines high contrast imaging techniques with high spectral resolution spectroscopy to observe exoplanets and determine characteristics such as chemical composition, temperature, and rotational velocities. It has been demonstrated in lab at the Caltech Exoplanet Technology Lab’s transmissive testbed that a fiber injection unit (FIU), in which a single mode optical fiber is used to couple to light from the exoplanet, could be used to direct exoplanet light to a high-resolution spectrograph, with robust performance and starlight suppression that exceeds conventional image-based starlight suppression by at least two orders of magnitude. We now demonstrate this technique in lab with a speckle nulling starlight suppression algorithm and corresponding Kalman filter estimator that achieves the same suppression as an exhaustive probing of the parameter space, but within a few probe cycles.

  1. UWB Tracking System Design with TDOA Algorithm

    Science.gov (United States)

    Ni, Jianjun; Arndt, Dickey; Ngo, Phong; Phan, Chau; Gross, Julia; Dusl, John; Schwing, Alan

    2006-01-01

    This presentation discusses an ultra-wideband (UWB) tracking system design effort using a tracking algorithm TDOA (Time Difference of Arrival). UWB technology is exploited to implement the tracking system due to its properties, such as high data rate, fine time resolution, and low power spectral density. A system design using commercially available UWB products is proposed. A two-stage weighted least square method is chosen to solve the TDOA non-linear equations. Matlab simulations in both two-dimensional space and three-dimensional space show that the tracking algorithm can achieve fine tracking resolution with low noise TDOA data. The error analysis reveals various ways to improve the tracking resolution. Lab experiments demonstrate the UWBTDOA tracking capability with fine resolution. This research effort is motivated by a prototype development project Mini-AERCam (Autonomous Extra-vehicular Robotic Camera), a free-flying video camera system under development at NASA Johnson Space Center for aid in surveillance around the International Space Station (ISS).

  2. Speckle Imaging and Spectroscopy of Kepler Exo-planet Transit Candidate Stars

    Science.gov (United States)

    Howell, Steve B.; Sherry, William; Horch, Elliott; Doyle, Laurance

    2010-02-01

    The NASA Kepler mission was successfully launched on 6 March 2009 and has begun science operations. Commissioning tests done early on in the mission have shown that for the bright sources, 10-15 ppm relative photometry can be achieved. This level assures we will detect Earth- like transits if they are present. ``Hot Jupiter" and similar large planet candidates have already been discovered and will be discussed at the Jan. AAS meeting as well as in a special issue of Science magazine to appear near years end. The plethora of variability observed is astounding and includes a number of eclipsing binaries which appear to have Jupiter and smaller size objects as an orbiting their body. Our proposal consists of three highly related objectives: 1) To continue our highly successful speckle imaging program which is a major component of defense to weed out false positive candidate transiting planets found by Kepler and move the rest to probable or certain exo-planet detections; 2) To obtain low resolution ``discovery" type spectra for planet candidate stars in order to provide spectral type and luminosity class indicators as well as a first look triage to eliminate binaries and rapid rotators; and 3) to obtain ~1Aresolution time ordered spectra of eclipsing binaries that are exo-planet candidates in order to obtain the velocity solution for the binary star, allowing its signal to be modeled and removed from the Keck or HET exo-planet velocity search. As of this writing, Kepler has produced a list of 227 exo-planet candidates which require false positive decision tree observations. Our proposed effort performs much of the first line of defense for the mission.

  3. Spatial sub-Rayleigh imaging analysis via speckle laser illumination.

    Science.gov (United States)

    Wang, Yunlong; Wang, Feiran; Liu, Ruifeng; Chen, Dongxu; Gao, Hong; Zhang, Pei; Li, Fuli

    2015-11-15

    It is commonly accepted that optical sub-Rayleigh imaging has potential application in many fields. In this Letter, by confining the divergence of the optical field, as well as the size of the illumination source, we show that the first-order averaged intensity measurement via speckle laser illumination can make an actual breakthrough on the Rayleigh limit. For a high-order algorithm, it has been reported that the autocorrelation function can be utilized to achieve the sub-Rayleigh feature. However, we find that this sub-Rayleigh feature for the high-order algorithm is limited only to binary objects, and the image will be distorted when a gray object is placed. This property encourages us to find the physics behind the high-order correlation imaging algorithm. We address these explanations in this Letter and find that for different types of high-order algorithm, there is always a "seat" in the right place from the cross-correlation function.

  4. Application of laser speckle displacement analysis to clinical dentistry

    Science.gov (United States)

    Cumberpatch, G. K. D.; Hood, J. A. A.

    1997-03-01

    Success of dental restorations is dependent on the integrity of the tooth/restoration interface. Distortion of teeth due to operative procedures has previously been measured using LVDT's and strain-gauges and has provided useful but limited information. This paper reports on the verification of a system for laser speckle photography and its use to quantitative distortions in teeth from matrix band application and the use of bonded composite resin restorations. Tightening of matrix bands around teeth results in an inward deformation of the cusps, increasing incrementally as the band is tightened. Deflections of 50 micrometer/cusp were recorded. A delayed recovery was noted consistent with the viscoelastic behavior of dentine. For bonded restorations recovery will place the adhesion interface in a state of tension when the band is released and may cause premature failure. Premolar teeth restored with bonded resin restorations exhibited inward displacement of cusps of 12 - 15 micrometer. Deformation was not within the buccal-lingual axis as suggested by prior studies. Molar teeth bonded with composite resin restoration exhibit complex and variable cusp displacement in both magnitude (0 - 30 micrometer) and direction. Complete and partial debonding could be detected. Interproximal cusp bending could be quantitated and lifting of the restoration from the cavity floor was detectable. Deformations evidenced indicate the tooth/restoration interface is in a stressed state and this may subsequently lead to failure. The technique has the potential to aid in development of restoration techniques that minimize residual stress.

  5. Innovative speckle noise reduction procedure in optical encryption

    Science.gov (United States)

    Vélez Zea, Alejandro; Fredy Barrera, John; Torroba, Roberto

    2017-05-01

    Encrypting techniques are currently of interest in the optical domain. A common issue when using coherent techniques is speckle noise which influences the final results. Most efforts to solve this issue were directed towards processing the output of the systems. Instead, we present an alternative approach where we seek to control the input to enhance the performance of these techniques. In particular, we analyze an encoding procedure with a joint transform correlator architecture as a case study. We first demonstrate the dependence of the output noise on the spatial distribution of the input, showing the existence of a neglected random correlation noise which contributes to the degradation of the output. We then propose a rearrangement of the input that results in a reduction of the noise level in the outcome. This rearrangement consists of separating the pixels of the input by introducing black pixels between them, keeping the usual remaining procedure unaltered. Our experimental approach opens up new possibilities for the applications of optical security techniques beyond the limitations imposed by noise.

  6. Laser speckle and skin cancer: skin roughness assessment

    Science.gov (United States)

    Lee, Tim K.; Tchvialeva, Lioudmila; Zeng, Haishan; McLean, David I.; Lui, Harvey

    2009-10-01

    Incidence of skin cancer has been increasing rapidly since the last few decades. Non-invasive optical diagnostic tools may improve the diagnostic accuracy. In this paper, skin structure, skin cancer statistics and subtypes of skin cancer are briefly reviewed. Among the subtypes, malignant melanoma is the most aggressive and dangerous; early detection dramatically improves the prognosis. Therefore, a non-invasive diagnostic tool for malignant melanoma is especially needed. In addition, in order for the diagnostic tool to be useful, it must be able to differentiate melanoma from common skin conditions such as seborrheic keratosis, a benign skin disease that resembles melanoma according to the well known clinical-assessment ABCD rule. The key diagnostic feature between these two diseases is surface roughness. Based on laser speckle contrast, our research team has recently developed a portable, optical, non-invasive, in-vivo diagnostic device for quantifying skin surface roughness. The methodology of our technique is described in details. Examining the preliminary data collected in a pilot clinical study for the prototype, we found that there was a difference in roughness between melanoma and seborrheic keratosis. In fact, there was a perfect cutoff value for the two diseases based on our initial data.

  7. Vibration isolation techniques suitable for portable electronic speckle pattern interferometry

    Science.gov (United States)

    Findeis, Dirk M.; Gryzagoridis, Jasson; Rowland, David R.

    2002-06-01

    Electronic Speckle Pattern Interferometry (ESPI) and Digital Shearography are optical interference techniques, suitable for non-destructive inspection procedures. Due to the stringent vibration isolation conditions required for ESPI, the technique is mainly suited for laboratory based inspection procedures, which cannot be said for Digital Shearography. On the other hand, the interference patterns obtained using ESPI exhibit better fringe definition and contrast than those obtained using Digital Shearography. The image quality of Digital Shearography can be improved by introducing phase stepping and unwrapping techniques, but these methods add a level of complexity to the inspection system and reduce the image refresh rate of the overall process. As part of a project to produce a low cost portable ESPI system suitable for industrial applications, this paper investigates various methods of minimizing the impact of environmental vibration on the ESPI technique. This can be achieved by effectively 'freezing' the object movement during the image acquisition process. The methods employed include using a high-powered infra-red laser, which is continuously pulsed using an electronic signal generator as well as a mechanical chopper. The effect of using a variable shutter speed camera in conjunction with custom written software acquisition routines is also studied. The techniques employed are described and are applied to selected samples. The initial results are presented and analyzed. Conclusions are drawn and their impact on the feasibility of a portable ESPI system discussed.

  8. In vivo lateral blood flow velocity measurement using speckle size estimation.

    Science.gov (United States)

    Xu, Tiantian; Hozan, Mohsen; Bashford, Gregory R

    2014-05-01

    In previous studies, we proposed blood measurement using speckle size estimation, which estimates the lateral component of blood flow within a single image frame based on the observation that the speckle pattern corresponding to blood reflectors (typically red blood cells) stretches (i.e., is "smeared") if blood flow is in the same direction as the electronically controlled transducer line selection in a 2-D image. In this observational study, the clinical viability of ultrasound blood flow velocity measurement using speckle size estimation was investigated and compared with that of conventional spectral Doppler of carotid artery blood flow data collected from human patients in vivo. Ten patients (six male, four female) were recruited. Right carotid artery blood flow data were collected in an interleaved fashion (alternating Doppler and B-mode A-lines) with an Antares Ultrasound Imaging System and transferred to a PC via the Axius Ultrasound Research Interface. The scanning velocity was 77 cm/s, and a 4-s interval of flow data were collected from each subject to cover three to five complete cardiac cycles. Conventional spectral Doppler data were collected simultaneously to compare with estimates made by speckle size estimation. The results indicate that the peak systolic velocities measured with the two methods are comparable (within ±10%) if the scan velocity is greater than or equal to the flow velocity. When scan velocity is slower than peak systolic velocity, the speckle stretch method asymptotes to the scan velocity. Thus, the speckle stretch method is able to accurately measure pure lateral flow, which conventional Doppler cannot do. In addition, an initial comparison of the speckle size estimation and color Doppler methods with respect to computational complexity and data acquisition time indicated potential time savings in blood flow velocity estimation using speckle size estimation. Further studies are needed for calculation of the speckle stretch method

  9. INNER TRACKING

    CERN Multimedia

    P. Sharp

    The CMS Inner Tracking Detector continues to make good progress. The Objective for 2006 was to complete all of the CMS Tracker sub-detectors and to start the integration of the sub-detectors into the Tracker Support Tube (TST). The Objective for 2007 is to deliver to CMS a completed, installed, commissioned and calibrated Tracking System (Silicon Strip and Pixels) aligned to < 100µ in April 2008 ready for the first physics collisions at LHC. In November 2006 all of the sub-detectors had been delivered to the Tracker Integration facility (TIF) at CERN and the tests and QA procedures to be carried out on each sub-detector before integration had been established. In December 2006, TIB/TID+ was integrated into TOB+, TIB/TID- was being prepared for integration, and TEC+ was undergoing tests at the final tracker operating temperature (-100 C) in the Lyon cold room. In February 2007, TIB/TID- has been integrated into TOB-, and the installation of the pixel support tube and the services for TI...

  10. Stem cell tracking by nanotechnologies.

    Science.gov (United States)

    Villa, Chiara; Erratico, Silvia; Razini, Paola; Fiori, Fabrizio; Rustichelli, Franco; Torrente, Yvan; Belicchi, Marzia

    2010-03-12

    Advances in stem cell research have provided important understanding of the cell biology and offered great promise for developing new strategies for tissue regeneration. The beneficial effects of stem cell therapy depend also by the development of new approachs for the track of stem cells in living subjects over time after transplantation. Recent developments in the use of nanotechnologies have contributed to advance of the high-resolution in vivo imaging methods, including positron emission tomography (PET), single-photon emission tomography (SPECT), magnetic resonance (MR) imaging, and X-Ray computed microtomography (microCT). This review examines the use of nanotechnologies for stem cell tracking.

  11. Vessel packaging effect in laser speckle contrast imaging and laser Doppler imaging

    Science.gov (United States)

    Fredriksson, Ingemar; Larsson, Marcus

    2017-10-01

    Laser speckle-based techniques are frequently used to assess microcirculatory blood flow. Perfusion estimates are calculated either by analyzing the speckle fluctuations over time as in laser Doppler flowmetry (LDF), or by analyzing the speckle contrast as in laser speckle contrast imaging (LSCI). The perfusion estimates depend on the amount of blood and its speed distribution. However, the perfusion estimates are commonly given in arbitrary units as they are nonlinear and depend on the magnitude and the spatial distribution of the optical properties in the tissue under investigation. We describe how the spatial confinement of blood to vessels, called the vessel packaging effect, can be modeled in LDF and LSCI, which affect the Doppler power spectra and speckle contrast, and the underlying bio-optical mechanisms for these effects. As an example, the perfusion estimate is reduced by 25% for LDF and often more than 50% for LSCI when blood is located in vessels with an average diameter of 40 μm, instead of being homogeneously distributed within the tissue. This significant effect can be compensated for only with knowledge of the average diameter of the vessels in the tissue.

  12. Speckle reduction in optical coherence tomography by two-step image registration.

    Science.gov (United States)

    Zhang, Hang; Li, Zhongliang; Wang, Xiangzhao; Zhang, Xiangyang

    2015-03-01

    The image quality of optical coherence tomography can be severely influenced by speckle noise (i.e., signal-degrading speckle). Averaging multiple B-scans can effectively suppress speckle noise. Because of sample motion, images subject to averaging must be aligned exactly. We propose a two-step image registration scheme that combines global and local registrations for speckle reduction by the averaging of multiple B-scans. The method begins with a global registration to compensate for overall motion, which is estimated based on the rigid transformation model involving translation and rotation. Then each A-scan is aligned by cross-correlation using a graph-based algorithm, followed by a pixel subdivision method to improve smoothness in local registration. The method does not rely on any information about the retinal layer boundaries. We have applied this method to the registration of macular optical coherence tomography images. The results show the reduction of speckle noise and the enhanced visualization of layer structures. A signal-to-noise ratio improvement of nearly the square root of the number of averaged B-scans and a contrast-to-noise ratio improvement of around 11 are achieved through our method.

  13. Evaluating multi-exposure speckle imaging estimates of absolute autocorrelation times.

    Science.gov (United States)

    Kazmi, S M Shams; Wu, Rebecca K; Dunn, Andrew K

    2015-08-01

    Multi-exposure speckle imaging (MESI) is a camera-based flow-imaging technique for quantitative blood-flow monitoring by mapping the speckle-contrast dependence on camera exposure duration. The ability of laser speckle contrast imaging to measure the temporal dynamics of backscattered and interfering coherent fields, in terms of the accuracy of autocorrelation measurements, is a major unresolved issue in quantitative speckle flowmetry. MESI fits for a number of parameters including an estimate of the electric field autocorrelation decay time from the imaged speckles. We compare the MESI-determined correlation times in vitro and in vivo with accepted true values from direct temporal measurements acquired with a photon-counting photon-multiplier tube and an autocorrelator board. The correlation times estimated by MESI in vivo remain on average within 14±11% of those obtained from direct temporal autocorrelation measurements, demonstrating that MESI yields highly comparable statistics of the time-varying fields that can be useful for applications seeking not only quantitative blood flow dynamics but also absolute perfusion.

  14. Study of microparticles' anomalous diffusion in active bath using speckle light fields (Presentation Recording)

    Science.gov (United States)

    Pince, Ercag; Sabareesh, Sabareesh K. P.; Volpe, Giorgio; Gigan, Sylvain; Volpe, Giovanni S.

    2015-08-01

    Particles undergoing a stochastic motion within a disordered medium is a ubiquitous physical and biological phenomenon. Examples can be given from organelles as molecular machines of cells performing physical tasks in a populated cytoplasm to human mobility in patchy environment at larger scales. Our recent results showed that it is possible to use the disordered landscape generated by speckle light fields to perform advanced manipulation tasks at the microscale. Here, we use speckle light fields to study the anomalous diffusion of micron size silica particles (5 μm) in the presence of active microswimmers. The microswimmers we used in the experiments are motile bacteria, Escherichia coli (E.coli). They constitute an active background constantly agitating passive silica particles within complex optical potentials. The speckle fields are generated by mode mixing inside a multimode optical fiber where a small amount of incident laser power (maximum power = 12 μW/μm2) is needed to obtain an effective random landscape pattern for the purpose of optical manipulation. We experimentally show how complex potentials contribute to the anomalous diffusion of silica particles undergoing collisions with swimming bacteria. We observed an enhanced diffusion of particles interacting with the active bath of E.coli inside speckle light fields: this effect can be tuned and controlled by varying the intensity and the statistical properties of the speckle pattern. Potentially, these results could be of interest for many technological applications, such as the manipulation of microparticles inside optically disordered media of biological interests.

  15. Point-wise and whole-field laser speckle intensity fluctuation measurements applied to botanical specimens

    Science.gov (United States)

    Zhao, Yang; Wang, Junlan; Wu, Xiaoping; Williams, Fred W.; Schmidt, Richard J.

    1997-12-01

    Based on multi-scattering speckle theory, the speckle fields generated by plant specimens irradiated by laser light have been studied using a pointwise method. In addition, a whole-field method has been developed with which entire botanical specimens may be studied. Results are reported from measurements made on tomato and apple fruits, orange peel, leaves of tobacco seedlings, leaves of shihu seedlings (a Chinese medicinal herb), soy-bean sprouts, and leaves from an unidentified trailing houseplant. Although differences where observed in the temporal fluctuations of speckles that could be ascribed to differences in age and vitality, the growing tip of the bean sprout and the shihu seedling both generated virtually stationary speckles such as were observed from boiled orange peel and from localised heat-damaged regions on apple fruit. Our results suggest that both the identity of the botanical specimen and the site at which measurements are taken are likely to critically affect the observation or otherwise of temporal fluctuations of laser speckles.

  16. Time-resolved granular dynamics of a rotating drum in a slumping regime as revealed by speckle visibility spectroscopy

    Directory of Open Access Journals (Sweden)

    Zivkovic V.

    2017-01-01

    Full Text Available Granular materials in rotating drums are of wide interest not only because of their extensive use in the industrial contexts, but also as model systems in the study of natural disasters, such as avalanches or landslides. Most of available experimental methods are restricted to surface layer flows and dilute systems whilst the remainder can only resolve the granular dynamics to a fine scale with relatively poor temporal resolution or vice versa. In contrast, speckle visibility spectroscopy (SVS is able to resolve the average of the three components of motion of grains in dense systems in small volume of granular media several layer deep with spatio-temporal resolutions that allow the probing of the granular micro-dynamics. We have used this technique to study granular dynamics of surface avalanche flow in the slumping regime using both spherical glass and irregular sand particles. Although results are very similar, we determined that visually observed compaction at the beginning of avalanche process for irregular sand particles influence time evolution of the particle fluctuation velocity during avalanches.

  17. Time-resolved granular dynamics of a rotating drum in a slumping regime as revealed by speckle visibility spectroscopy

    Science.gov (United States)

    Zivkovic, V.; Yang, H.; Zheng, G.; Biggs, M.

    2017-06-01

    Granular materials in rotating drums are of wide interest not only because of their extensive use in the industrial contexts, but also as model systems in the study of natural disasters, such as avalanches or landslides. Most of available experimental methods are restricted to surface layer flows and dilute systems whilst the remainder can only resolve the granular dynamics to a fine scale with relatively poor temporal resolution or vice versa. In contrast, speckle visibility spectroscopy (SVS) is able to resolve the average of the three components of motion of grains in dense systems in small volume of granular media several layer deep with spatio-temporal resolutions that allow the probing of the granular micro-dynamics. We have used this technique to study granular dynamics of surface avalanche flow in the slumping regime using both spherical glass and irregular sand particles. Although results are very similar, we determined that visually observed compaction at the beginning of avalanche process for irregular sand particles influence time evolution of the particle fluctuation velocity during avalanches.

  18. Intraoperative laser speckle contrast imaging for monitoring cerebral blood flow: results from a 10-patient pilot study

    Science.gov (United States)

    Richards, Lisa M.; Weber, Erica L.; Parthasarathy, Ashwin B.; Kappeler, Kaelyn L.; Fox, Douglas J.; Dunn, Andrew K.

    2012-02-01

    Monitoring cerebral blood flow (CBF) during neurosurgery can provide important physiological information for a variety of surgical procedures. Although multiple intraoperative vascular monitoring technologies are currently available, a quantitative method that allows for continuous monitoring is still needed. Laser speckle contrast imaging (LSCI) is an optical imaging method with high spatial and temporal resolution that has been widely used to image CBF in animal models in vivo. In this pilot clinical study, we adapted a Zeiss OPMI Pentero neurosurgical microscope to obtain LSCI images by attaching a camera and a laser diode. This LSCI adapted instrument has been used to acquire full field flow images from 10 patients during tumor resection procedures. The patient's ECG was recorded during acquisition and image registration was performed in post-processing to account for pulsatile motion artifacts. Digital photographs confirmed alignment of vasculature and flow images in four cases, and a relative change in blood flow was observed in two patients after bipolar cautery. The LSCI adapted instrument has the capability to produce real-time, full field CBF image maps with excellent spatial resolution and minimal intervention to the surgical procedure. Results from this study demonstrate the feasibility of using LSCI to monitor blood flow during neurosurgery.

  19. Single-shot speckle reduction and dispersion compensation in optical coherence tomography by compounding fractional Fourier domains.

    Science.gov (United States)

    Lippok, Norman; Nielsen, Poul; Vanholsbeeck, Frédérique

    2013-06-01

    We present speckle suppression and dispersion compensation for Fourier-domain optical coherence tomography based on fractional Fourier transforms of a single A scan. A 1.54-fold reduction in speckle contrast was achieved with group velocity dispersion compensation. The method is demonstrated on biological samples using a swept source configuration at 1310 nm and a spectral-domain system at 840 nm.

  20. Applicability of quantitative optical imaging techniques for intraoperative perfusion diagnostics: a comparison of laser speckle contrast imaging, sidestream dark-field microscopy, and optical coherence tomography

    Science.gov (United States)

    Jansen, Sanne M.; de Bruin, Daniel M.; Faber, Dirk J.; Dobbe, Iwan J. G. G.; Heeg, Erik; Milstein, Dan M. J.; Strackee, Simon D.; van Leeuwen, Ton G.

    2017-08-01

    Patient morbidity and mortality due to hemodynamic complications are a major problem in surgery. Optical techniques can image blood flow in real-time and high-resolution, thereby enabling perfusion monitoring intraoperatively. We tested the feasibility and validity of laser speckle contrast imaging (LSCI), optical coherence tomography (OCT), and sidestream dark-field microscopy (SDF) for perfusion diagnostics in a phantom model using whole blood. Microvessels with diameters of 50, 100, and 400 μm were constructed in a scattering phantom. Perfusion was simulated by pumping heparinized human whole blood at five velocities (0 to 20 mm/s). Vessel diameter and blood flow velocity were assessed with LSCI, OCT, and SDF. Quantification of vessel diameter was feasible with OCT and SDF. LSCI could only visualize the 400-μm vessel, perfusion units scaled nonlinearly with blood velocity. OCT could assess blood flow velocity in terms of inverse OCT speckle decorrelation time. SDF was not feasible to measure blood flow; however, for diluted blood the measurements were linear with the input velocity up to 1 mm/s. LSCI, OCT, and SDF were feasible to visualize blood flow. Validated blood flow velocity measurements intraoperatively in the desired parameter (mL·g-1) remain challenging.