Digital simulation of pulsed ultrasonic waveforms.

abstract：:Modern ultrasound Doppler systems are facing the problem of processing increasingly shorter data sets. Spectral analysis of the strongly nonstationary Doppler signal needs to shorten the analysis window while maintaining a low variance and high resolution spectrum. Color flow imaging requires estimation of the Doppler...

journal_title：Ultrasonic imaging

authors： Herment A,Giovannelli JF

更新日期：1995-01-01 00:00:00

abstract：:Hall effect imaging is an ultrasound-based method of mapping spatial variations in the dielectric constants of an acoustically-uniform sample. This paper presents three-dimensional Hall effect images of phantoms obtained by scanning a single transducer across a two-dimensional grid, effectively simulating two-dimensio...

journal_title：Ultrasonic imaging

authors： Wen H

更新日期：1999-07-01 00:00:00

abstract：:Muscle fatigue often occurs over a long period of exercise, and it can increase the risk of muscle injury. Evaluating the state of muscle fatigue can avoid unnecessary overtraining and injury of the muscle. Ultrasound imaging can non-invasively visualize muscle tissue in real-time. Image entropy is commonly used to ch...

journal_title：Ultrasonic imaging

authors： Li P,Yang X,Yin G,Guo J

更新日期：2020-11-01 00:00:00

abstract：:A Fourier transform (FT)-based technique for forming parallel receive beams has been previously employed to increase the imaging frame rate in ultrasonic imaging. However, the image quality in FT-based parallel reconstruction is degraded because differences in range focusing delays are ignored and a wide transmit beam...

journal_title：Ultrasonic imaging

authors： Li ML,Li PC

更新日期：2003-04-01 00:00:00

abstract：:Optimal transmit phasing has been proposed to increase contrast-to-tissue ratio (CTR) by relatively phasing the tissue and leakage harmonic components to cancel each other out for tissue-background suppression in harmonic imaging. Since most clinical systems are only equipped with a bipolar square-wave pulser, effecti...

journal_title：Ultrasonic imaging

authors： Shen CC,Yang YC,Chen WS

更新日期：2010-01-01 00:00:00

abstract：:Attenuation measurements of various tissue mimicking phantoms and three different groups of patients were obtained using a modified commercial sector scanner. Estimates of attenuation were made using the spectral shift method with mean frequencies at different depths of a region of interest being obtained by both zero...

journal_title：Ultrasonic imaging

authors： Garra BS,Shawker TH,Nassi M,Russell MA

更新日期：1984-10-01 00:00:00

abstract：:Regional anesthesia is preferred over general anesthesia for many surgical procedures; however, challenges associated with poor image guidance limit its widespread acceptance as a viable alternative. In B-mode ultrasound images, the current standard for guidance, nerves can be difficult to visualize due to their simil...

journal_title：Ultrasonic imaging

authors： Palmeri ML,Dahl JJ,MacLeod DB,Grant SA,Nightingale KR

更新日期：2009-07-01 00:00:00

abstract：:Ultrasonic coda wave analysis techniques localize defects in fields such as seismography and nondestructive testing. In medical ultrasound, these techniques might provide novel mapping of tissue properties in diseases characterized by local fibrosis. In this work, we present an approach for localizing variation in sca...

journal_title：Ultrasonic imaging

authors： Lindsey BD,Collins GC

更新日期：2020-01-01 00:00:00

abstract：:For a class of scattering objects the mean separation between the scatterers is determined. Over a range of frequencies, ultrasonic back-scattered pressure signals are recorded. It is suggested to derive the mean spacing of an unknown scattering object by employing Fourier analysis and comparing the signal with signal...

journal_title：Ultrasonic imaging

authors： Koch I

更新日期：1983-10-01 00:00:00

abstract：:Mean frequency estimators as used in pulsed Doppler ultrasound equipment should provide an accurate (quality) and consistent (robustness) estimate over a wide range of signal conditions. In a simplified signal model, the main parameters to consider are the noise level, mean frequency, bandwidth and power of both the D...

journal_title：Ultrasonic imaging

authors： Brands PJ,Hoeks AP

更新日期：1992-10-01 00:00:00

abstract：:Mathematical techniques are described for analyzing tongue shapes obtained with ultrasound images. The surface of the mid-sagittal section of the tongue was approximated by discrete points. In turn, these points were used to approximate position, slope and curvature of the tongue surface at a fixed time during speech....

journal_title：Ultrasonic imaging

authors： Morrish KA,Stone M,Sonies BC,Kurtz D,Shawker T

更新日期：1984-01-01 00:00:00

abstract：:The amplitude and frequency contents of a received ultrasound pulse depends on the spatial pressure amplitude distribution of the sound field, as produced by the transducer in the medium, and on the position and orientation of the reflecting surface in this field. Often, the geometry of the reflecting surface and the ...

journal_title：Ultrasonic imaging

authors： Linssen FM,Hoeks AP

更新日期：1990-10-01 00:00:00

abstract：:It may be possible to diagnose and monitor scarring, inflammation and edema in transplant kidney using reconstructive ultrasound elasticity imaging. Kidney elasticity is expected to change dramatically with scar, and to a lesser degree, with acute inflammation and edema. The hypothesis that changes in kidney elasticit...

journal_title：Ultrasonic imaging

authors： Emelianov SY,Lubinski MA,Skovoroda AR,Erkamp RQ,Leavey SF,Wiggins RC,O'Donnell M

更新日期：2000-07-01 00:00:00

abstract：:Two-dimensional echocardiography (2-D echo) imaging is a more attractive clinical tool than other modalities that either involve radiation exposure or are too slow to image heart motion in real-time. Computer-aided analysis of left ventricular(LV) wall motion provides quantitative parameters for diagnosis. This study ...

journal_title：Ultrasonic imaging

authors： Chen T,Chen TP,Tsai LM

更新日期：1997-04-01 00:00:00

abstract：:Acoustic radiation force (ARF) has become a common excitation mechanism in elasticity imaging. The high acoustic intensities and subsequent generation of harmonics, however, hamper the effectiveness of using conventional radiofrequency (rf) tracking to investigate the dynamics of tissues and catheter-based transducers...

journal_title：Ultrasonic imaging

authors： Bouchard RR,Van Soest G,Trahey GE,Van Der Steen AF

更新日期：2009-01-01 00:00:00

abstract：:Portable ultrasound is recently emerging as a new medical imaging modality featuring high portability, easy connectivity, and real-time on-site diagnostic ability. However, it does not yet provide ultrasound elastography function that enables the diagnosis of malignant lesions using elastic properties. This is mainly ...

journal_title：Ultrasonic imaging

authors： Shin B,Jeon S,Ryu J,Kwon HJ

更新日期：2017-11-01 00:00:00

abstract：:Acoustic Radiation Force Impulse (ARFI) imaging is a method for characterizing local variations in tissue mechanical properties. In this method, a single ultrasonic transducer array is used to both apply temporally short localized radiation forces within tissue and to track the resulting displacements through time. In...

journal_title：Ultrasonic imaging

authors： Nightingale K,Bentley R,Trahey G

更新日期：2002-07-01 00:00:00

abstract：:A new online signal processing technique is described to reduce speckle noise in ultrasound images. In the imaging system, a focused piston transducer is divided into thirty-two sectors. In the receive mode, parallel signal processing arranges the sectors into eight maltese crosses. The rf signals of the perpendicular...

journal_title：Ultrasonic imaging

authors： Smith SW,von Ramm OT

更新日期：1988-07-01 00:00:00

abstract：:In this paper, quantitative tomographic reconstructions of biological tissue are presented. First, the experimental setup and a hybrid filtered backpropagation (FBP) technique are briefly described. Using this technique, which includes exact backpropagation of data prior to reconstruction by means of the classical FBP...

journal_title：Ultrasonic imaging

authors： Sponheim N,Gelius LJ,Johansen I,Stamnes JJ

更新日期：1994-01-01 00:00:00

abstract：:Coherent speckle is a source of image noise in ultrasonic B-mode imaging. The use of multiple imaging frequencies has been suggested as a technique for speckle contrast reduction. This technique involves the averaging of images whose speckle patterns have been modified by a change in the spectrum of the transmitted or...

journal_title：Ultrasonic imaging

authors： Trahey GE,Allison JW,Smith SW,von Ramm OT

更新日期：1986-07-01 00:00:00

abstract：:Anova and "dummy variables" least squares regression methods are used to investigate the dependence of ultrasound propagation velocity on the presence or absence of fat and on the rank ordered level of cirrhosis in fixed human liver. Cirrhosis is found to affect velocity in a nonlinear fashion, while fat depresses the...

journal_title：Ultrasonic imaging

authors： Zimmermann KP,Smith JC

更新日期：1983-07-01 00:00:00

abstract：:Our group has proposed the concept of subharmonic aided pressure estimation (SHAPE) utilizing microbubble-based ultrasound contrast agent signals for the noninvasive estimation of hydrostatic blood pressures. An experimental system for in vitro SHAPE was constructed based on two single-element transducers assembled co...

journal_title：Ultrasonic imaging

authors： Halldorsdottir VG,Dave JK,Leodore LM,Eisenbrey JR,Park S,Hall AL,Thomenius K,Forsberg F

更新日期：2011-07-01 00:00:00

abstract：:This paper addresses significant sources of electromagnetic noise in Hall effect imaging. Hall effect imaging employs large electrical pulses for signal generation and high sensitivity ultrasonic probes for signal reception. Coherent noise arises through various coupling mechanisms between the excitation pulse and the...

journal_title：Ultrasonic imaging

authors： Wen H,Bennett E,Wiesler DG

更新日期：1998-07-01 00:00:00

abstract：:Many noninvasive ultrasound techniques have been developed to explore mechanical properties of soft tissues. One of these methods, Localized Harmonic Motion Imaging (LHMI), has been proposed to be used for ultrasound surgery monitoring. In LHMI, dynamic ultrasound radiation-force stimulation induces displacements in a...

journal_title：Ultrasonic imaging

authors： Heikkilä J,Hynynen K

更新日期：2006-04-01 00:00:00

abstract：:Phased-array images have been obtained in vivo with a steered copolymer array operating at 2.5 MHz. The array was fabricated using 28 microns copolymer film, lambda/4 resonant at 21 MHz, which was bonded to a glass ceramic backing with a thin film bond. The 32 array elements were created by laser ablation of the conti...

journal_title：Ultrasonic imaging

authors： Goldberg RL,Smith SW,Brown LF

更新日期：1992-07-01 00:00:00

abstract：:An adaptive scan sequence is proposed for real-time ultrasound three-dimensional (3-D) imaging. Generally, the refresh rate of 3-D imaging is limited by the view window, resolution and sound speed in the human body. If the object is transformed or moved during the data set acquisition, the 3-D image will be distorted....

journal_title：Ultrasonic imaging

authors： Hashimoto H,Takeuchi Y

更新日期：2003-10-01 00:00:00

abstract：:In this work, we study linear array beamforming for vibro-acoustography systems. The goal of this research is to assess the feasibility of vibro-acoustography imaging systems based on linear arrays for clinical applications. The vibro-acoustography transducer is designed with two arrays driven by two continuous-wave o...

journal_title：Ultrasonic imaging

authors： Silva GT,Greenleaf JF,Fatemi M

更新日期：2004-01-01 00:00:00

abstract：:Previously reported data on the temperature dependence of propagation speed in tissues generally span only temperature ranges up to 60 degrees C. However, with the emerging use of thermal ablative therapies, information on variation in this parameter over higher temperature ranges is needed. Measurements of the ultras...

journal_title：Ultrasonic imaging

authors： Techavipoo U,Varghese T,Zagzebski JA,Stiles T,Frank G

更新日期：2002-10-01 00:00:00

abstract：:Generation of the second harmonic signal was studied for finite amplitude distortion based harmonic imaging. Acoustic field amplitudes along the range axis of a fixed focus transducer were measured using a PVDF needle hydrophone. Results indicated that on-axis amplitudes strongly depended on the f-number at both the f...

journal_title：Ultrasonic imaging

authors： Li PC,Shen CC

更新日期：1999-10-01 00:00:00

abstract：:Volume reconstruction method plays an important role in improving reconstructed volumetric image quality for freehand three-dimensional (3D) ultrasound imaging. By utilizing the capability of programmable graphics processing unit (GPU), we can achieve a real-time incremental volume reconstruction at a speed of 25-50 f...

journal_title：Ultrasonic imaging

authors： Wen T,Li L,Zhu Q,Qin W,Gu J,Yang F,Xie Y

更新日期：2017-07-01 00:00:00