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 attenuation coefficient. Local estimates exhibit large bias errors and a high degree of variability. This variability diminishes in the focal zone of the focussed transducer and in the far field of the unfocussed transducer.
journal_name
Ultrason Imagingjournal_title
Ultrasonic imagingauthors
Ophir J,Ghouse MA,Ferrari LAdoi
10.1177/016173468500700202subject
Has Abstractpub_date
1985-04-01 00:00:00pages
122-32issue
2eissn
0161-7346issn
1096-0910journal_volume
7pub_type
杂志文章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
pub_type: 杂志文章
doi:10.1177/0161734617716938
更新日期:2017-11-01 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
pub_type: 杂志文章
doi:10.1177/016173469201400302
更新日期:1992-07-01 00:00:00
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
pub_type: 杂志文章
doi:10.1177/016173469501700101
更新日期:1995-01-01 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
pub_type: 杂志文章
doi:10.1177/016173460302500401
更新日期:2003-10-01 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::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
pub_type: 杂志文章
doi:10.1177/016173460202400301
更新日期:2002-07-01 00:00:00
abstract::The methods of statistical pattern recognition have been applied to the problem of in vivo ultrasonic characterization of breast disease in humans. Backscattered A-mode signals obtained from a commercial pulse imaging system were used to generate a large set of potentially useful features. Using statistical tests, a s...
journal_title:Ultrasonic imaging
pub_type: 杂志文章
doi:10.1177/016173468300500107
更新日期:1983-01-01 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
pub_type: 杂志文章
doi:10.1177/016173468300500306
更新日期:1983-07-01 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::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::Conventional ultrasonic B-mode images qualitatively describe tissue structures but are unsuitable for quantitative analyses of scatterer properties. We have recently developed an ultrasonic parametric imaging technique based on the Nakagami statistical distribution that is able to quantify scatterer concentrations. Th...
journal_title:Ultrasonic imaging
pub_type: 杂志文章
doi:10.1177/016173460803000202
更新日期:2008-04-01 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::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
pub_type: 杂志文章
doi:10.1177/016173460602800203
更新日期:2006-04-01 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
pub_type: 杂志文章
doi:10.1177/016173468400600104
更新日期:1984-01-01 00:00:00
abstract::This study shows that the amplitude information of ultrasound echoes is carried mainly by the envelope peaks (EPs). It is first shown that the EPs in an A-line represent the maximum number of independent amplitude data. It is then demonstrated that the entire envelope could be approximately reconstructed from the EPs....
journal_title:Ultrasonic imaging
pub_type: 杂志文章
doi:10.1177/016173468801000403
更新日期:1988-10-01 00:00:00
abstract::A scalable architecture for forming real-time synthetic focus images is described and the design of a 256-channel system using currently-available technology is presented as an example implementation of the architecture. The parallelism of the system scales directly with the number of array elements and the image comp...
journal_title:Ultrasonic imaging
pub_type: 杂志文章
doi:10.1177/016173460302500303
更新日期:2003-07-01 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::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
pub_type: 杂志文章
doi:10.1177/016173468400600402
更新日期:1984-10-01 00:00:00
abstract::The propagation of pressure pulses of arbitrary time form in inhomogeneous attenuating media with characteristics similar to real biological tissues is considered. A mathematical model using the quasi-optical approximation is developed to solve the wave equation. Such a model proves to be convenient for computer reali...
journal_title:Ultrasonic imaging
pub_type: 杂志文章
doi:10.1177/016173469301500106
更新日期:1993-01-01 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
pub_type: 杂志文章
doi:10.1177/016173460202400404
更新日期:2002-10-01 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::This ex vivo study explores the relationship of ultrasonic attenuation and backscatter to dermal microarchitecture by comparing ultrasonic measurements of these parameters (11-27 MHz) to a microscopic analysis of three parameters describing the collagen distribution (mean thickness and spacing of collagen bundles alon...
journal_title:Ultrasonic imaging
pub_type: 杂志文章
doi:10.1177/016173460602800103
更新日期:2006-01-01 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::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::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
pub_type: 杂志文章
doi:10.1177/016173468300500405
更新日期:1983-10-01 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
pub_type: 杂志文章
doi:10.1177/016173469701900204
更新日期:1997-04-01 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
pub_type: 杂志文章
doi:10.1177/0161734616689464
更新日期:2017-07-01 00:00:00
abstract::Accurate tracking of tissue motion is critically important for several ultrasound elastography methods. In this study, we investigate the feasibility of using three published convolution neural network (CNN) models built for optical flow (hereafter referred to as CNN-based tracking) by the computer vision community fo...
journal_title:Ultrasonic imaging
pub_type: 杂志文章
doi:10.1177/0161734620902527
更新日期:2020-03-01 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
pub_type: 杂志文章
doi:10.1177/0161734619839648
更新日期:2019-07-01 00:00:00
abstract::The microbubble contrast agent destruction/replenishment technique has been widely applied to ultrasound-based blood flow estimation. The rate of increase of the time-intensity curve (TIC) due to microbubbles flowing into the region of interest as measured from B-mode images closely reflects the flow velocity. In this...
journal_title:Ultrasonic imaging
pub_type: 杂志文章
doi:10.1177/016173460803000301
更新日期:2008-07-01 00:00:00