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-dimensional phased-array signal reception. The experiments demonstrate the feasibility of volumetric Hall effect tomography and show the advantage of volumetric scans over planar scans. The images reflect several limitations of the current scanning method and point to directions for further hardware development. The inherent limitations of Hall effect imaging are also discussed in light of these results.
journal_name
Ultrason Imagingjournal_title
Ultrasonic imagingauthors
Wen Hdoi
10.1177/016173469902100303subject
Has Abstractpub_date
1999-07-01 00:00:00pages
186-200issue
3eissn
0161-7346issn
1096-0910journal_volume
21pub_type
杂志文章abstract::Behavior and limitations of the sinc basis method have been discovered during simulation studies. An iterative row-action method (ART) is compared with a full-matrix, least-squares solution (QR decomposition) and the problem of multiple solutions is discussed. Knowledge of the spatial distribution of scattered field e...
journal_title:Ultrasonic imaging
pub_type: 杂志文章
doi:10.1177/016173468901100103
更新日期:1989-01-01 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
pub_type: 杂志文章
doi:10.1177/016173468801000301
更新日期:1988-07-01 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
pub_type: 杂志文章
doi:10.1177/016173469201400404
更新日期:1992-10-01 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
pub_type: 杂志文章
doi:10.1177/016173460202400404
更新日期:2002-10-01 00:00:00
abstract::This paper describes a method for overcoming motion artifacts in synthetic aperture imaging. The method is based on a computer simulation study on the influence of target motion on synthetic aperture techniques. A region-based motion compensation approach is used in which only the axial motion is estimated and compens...
journal_title:Ultrasonic imaging
pub_type: 杂志文章
doi:10.1177/016173460202400202
更新日期:2002-04-01 00:00:00
abstract::Speckle noise is known to be signal-dependent in ultrasound imaging. Hence, separating noise from signal becomes a difficult task. This paper describes a wavelet-based method for reducing speckle noise. We derive from the model of the displayed ultrasound image the optimal wavelet-domain filter in the least mean-squar...
journal_title:Ultrasonic imaging
pub_type: 杂志文章
doi:10.1177/016173460002200201
更新日期:2000-04-01 00:00:00
abstract::An algorithm for deconvolution of medical ultrasound images is presented. The procedure involves estimation of the basic one-dimensional ultrasound pulse, determining the ratio of the covariance of the noise to the covariance of the reflection signal, and finally deconvolution of the rf signal from the transducer. Usi...
journal_title:Ultrasonic imaging
pub_type: 杂志文章
doi:10.1177/016173469301500204
更新日期:1993-04-01 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
pub_type: 杂志文章
doi:10.1177/016173460002200303
更新日期:2000-07-01 00:00:00
abstract::In recent years, adaptive minimum-variance (MV) beamforming has been successfully applied to medical ultrasound imaging, resulting in simultaneous improvement in imaging resolution and contrast. MV has high resolution and hence can provide accurate estimates of the target locations. However, the MV amplitude estimates...
journal_title:Ultrasonic imaging
pub_type: 杂志文章
doi:10.1177/0161734615600167
更新日期:2016-07-01 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
pub_type: 杂志文章
doi:10.1177/016173469902100401
更新日期:1999-10-01 00:00:00
abstract::Tracking large deformations in tissue using ultrasound can enable the reconstruction of nonlinear elastic parameters, but poses a challenge to displacement estimation algorithms. Such large deformations have to be broken up into steps, each of which contributes an estimation error to the final accumulated displacement...
journal_title:Ultrasonic imaging
pub_type: 杂志文章
doi:10.1177/0161734613479246
更新日期:2013-04-01 00:00:00
abstract::In pulsed Doppler ultrasound systems, the ultrasound radiofrequency (RF) signals received can be employed to estimate noninvasively the time-dependent blood velocity distribution within and artery. The RF signals are composed of signals originating from clutter (e.g., vessel walls) and scatterers (e.g., red blood cell...
journal_title:Ultrasonic imaging
pub_type: 杂志文章
doi:10.1177/016173469701900101
更新日期:1997-01-01 00:00:00
abstract::Peripheral artery disease is often asymptomatic, and various imaging and nonimaging techniques have been used for assessment and monitoring treatments. This study is designed to demonstrate the ability of photoacoustic imaging to noninvasively determine changes in tissue oxygenation that occur in mice's hind limb skel...
journal_title:Ultrasonic imaging
pub_type: 杂志文章
doi:10.1177/0161734619862287
更新日期:2019-09-01 00:00:00
abstract::In medical ultrasound imaging, two-dimensional (2-D) array transducers are desirable to implement dynamic focusing and phase aberration correction in two dimensions as well as volumetric imaging. Unfortunately, the small size of a 2-D array element results in a small clamped capacitance and a large electrical impedanc...
journal_title:Ultrasonic imaging
pub_type: 杂志文章
doi:10.1177/016173469501700202
更新日期:1995-04-01 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
pub_type: 杂志文章
doi:
更新日期:2009-01-01 00:00:00
abstract::It is well-documented in literature that benign breast lesions, such as fibroadenomas, are loosely bonded to their surrounding tissue and tend to slip under a small quasi-static compression, whereas malignant lesions being firmly bonded to their surrounding tissue do not slip. Recent developments in quasi-static ultra...
journal_title:Ultrasonic imaging
pub_type: 杂志文章
doi:10.1177/0161734616686746
更新日期:2017-05-01 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
pub_type: 杂志文章
doi:10.1177/016173461003200103
更新日期:2010-01-01 00:00:00
abstract::Global and local attenuation coefficient estimations were performed in a phantom using a pulse echo method based on the rate of decay of zero crossing density. Focussed and unfocussed 3.5 MHz transducers were used. It was found that good global estimates could be made with either transducer over a 2:1 range of attenua...
journal_title:Ultrasonic imaging
pub_type: 杂志文章
doi:10.1177/016173468500700202
更新日期:1985-04-01 00:00:00
abstract::This paper presents a new beamforming technique, in which ultrasound waves are focused at the display pixels on the Cartesian coordinates, rather than sampling points located on the uniformly-separated scanlines on either the polar or Cartesian coordinates. Consequently, this method does not require a digital scan con...
journal_title:Ultrasonic imaging
pub_type: 杂志文章
doi:10.1177/016173460102300101
更新日期:2001-01-01 00:00:00
abstract::Ultrasonic waveform data from a tissue-mimicking phantom containing low contrast targets was digitized, stored and processed prior to creating and displaying ultrasonic images. Speckle reduction was performed by digital filtering of the waveform data with appropriately spaced and weighted digital filters, prior to bot...
journal_title:Ultrasonic imaging
pub_type: 杂志文章
doi:10.1177/016173468700900202
更新日期:1987-04-01 00:00:00
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journal_title:Ultrasonic imaging
pub_type: 杂志文章
doi:10.1177/016173460602800203
更新日期:2006-04-01 00:00:00
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journal_title:Ultrasonic imaging
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doi:10.1177/0161734617716938
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journal_title:Ultrasonic imaging
pub_type: 杂志文章,评审
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journal_title:Ultrasonic imaging
pub_type: 杂志文章
doi:10.1177/016173468400600104
更新日期:1984-01-01 00:00:00
abstract::Statistical pattern recognition procedures allow a quantitative description of ultrasound-B-scan image texture. According to well-established animal models, different types of fatty liver disease were induced in female Wistar rats. For the correlation of the computerized ultrasound image with its underlying histology ...
journal_title:Ultrasonic imaging
pub_type: 杂志文章
doi:10.1177/016173469001200302
更新日期:1990-07-01 00:00:00
abstract::The theory of diffraction tomography for two-dimensional objects within the Born approximation is presented for cases where the scattered field is measured over arbitrarily shaped boundaries surrounding the object. Reconstruction algorithms are presented for both plane wave (parallel beam) and cylindrical wave (fan be...
journal_title:Ultrasonic imaging
pub_type: 杂志文章
doi:10.1177/016173468400600207
更新日期:1984-04-01 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
pub_type: 杂志文章
doi:10.1177/016173461103300301
更新日期:2011-07-01 00:00:00
abstract::The aim of this study was to assess whether acoustic structure quantification (ASQ) can differentiate normal from pathological thyroid parenchyma in patients with diffuse autoimmune thyroid disease (AITD). We evaluated 83 subjects (72 [87%] women and 11 [13%] men) aged 19 to 94 years with a mean age of 53 years. We pe...
journal_title:Ultrasonic imaging
pub_type: 杂志文章
doi:10.1177/0161734615580766
更新日期:2016-03-01 00:00:00
abstract::To perform computer-aided diagnosis of the thyroid nodules on ultrasound images, the location and boundary of nodules should be clearly defined. However, the identification of thyroid nodule boundary is a difficult issue due to the biological characteristics of the nodules, the physics and quality of ultrasound imagin...
journal_title:Ultrasonic imaging
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更新日期:2019-07-01 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
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