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Four-dimensional (4D), or equivalently, 3D + time, analysis is useful for comprehensive assessment cardiac function, especially in the asymmetric left ventricle (LV) after myocardial infarction (MI). This paper presents a 4D-model-based method for ultrasound assessment of cardiac contractile function in mice. Echocardiographic image sequences were acquired at high frequency (30 MHz) from the hearts...
In this paper, a computational method based on finite element method is presented to evaluate the propagation of acoustic waves through three-dimensional phononic crystals consisting of simple cubic (SC), body-centered cubic (BCC) or face-centered cubic (FCC) array spheres embedded in a host. Complete and accurate band structure information is obtained to identify the band gaps and eigenmodes. The...
This paper is in two parts and addresses two ways of getting more information out of the RF signal from a three-dimensional (3D) mechanically-swept medical ultrasound scanner. The first topic is the use of non-blind deconvolution to improve the clarity of the data, particularly in the direction perpendicular to the individual B-scans. The second topic is strain imaging. We present a robust and efficient...
The field of tissue engineering requires improved methods to monitor tissue growth and function as well as the degradation of biomaterial scaffolds following implantation. Invasive methods of monitoring, such as histology or direct mechanical measurements, are less than ideal. Non-invasive imaging techniques, such as magnetic resonance imaging (MRI), X-ray computed tomography (CT) or conventional...
Quantitative high-frequency ultrasound (QHFU) imaging methods are under investigation to evaluate their ability to detect small nodal metastases in lymph nodes freshly dissected from cancer patients. To apply these methods, a critical preprocessing step is 3D segmentation of the lymph-node ultrasound echo-signal dataset. Segmenting the residual fat layer and the lymph node is critical in order to...
We are investigating utilizing ARFI imaging to guide prostate needle biopsy. Our previous ex vivo study demonstrated that ARFI imaging using a VF10-5 linear array was able to visualize the internal anatomy and suspicious lesions in the prostate, which may help improve the diagnostic accuracy of prostate needle biopsy. The objective of this study is to implement ARFI techniques on a 3D wobbler rectal...
Freehand 3D ultrasound imaging has been growing in popularity. However, the unavoidable reconstruction errors introduced by freehand motion have limited its usefulness. To overcome this, freehand ultrasound systems have been augmented with external tracking sensors to produce accurate 3D images in mainly experimental settings, but these systems have yet to be accepted for general clinical use. In...
It is important of diagnosing not only primary tumors but also metastases accurately. Recently, we have established murine lymph node metastasis model and developed a new method to reconstruct the two- and three-dimensional (2D/3D) vessel structures in the model by using nanobubbles (NBs) and high-frequency ultrasound imaging system. In the present study, we investigated the characteristics of 2D/3D...
Fibroscanreg (Echosens, Paris, France) is a parametric transient elastography based device used to quantify liver fibrosis by following the propagation of a low frequency shear wave and measuring the mean Young's modulus of the liver. This device has been successfully applied to homogeneous tissues such as liver in patients with chronic hepatic diseases. Current developments in transient elastography...
Abersim, a simulation package for 3D nonlinear acoustic wave propagation of wide-band pulses from arbitrary transducers, is presented. This study validates the 3D diffraction and attenuation produced by Abersim, by comparing them to those obtained using Field II. For the presented test cases, the axial pressure amplitude and the RMS values deviate less than 0.7 dB, both for axis-symmetric and array...
The aim of this study was to validate cardiac output (CO) values obtained by fully automated segmentation of the left ventricle (LV) against CO measured from the volume flow in the pulmonary artery. Segmentation of the LV in 3D echographic images may substantially support clinical diagnosis of (congenital) heart disease. Assumptions about shape and appearance of the heart are often incorporated in...
Microbubbles provide the basis for perfusion measurement, early detection of molecular signatures of disease and as a vehicle for drug, or gene, delivery. Although the response of a single microbubble to ultrasound has been characterized by radially symmetric 1D models and high speed camera-based experiments, a plethora of mechanisms, such as bubble-bubble interaction, and adherent bubble response...
We have previously developed regularized 2D and 3D elastography methods using Dynamic Programming (DP). A cost function which incorporates similarity of echo amplitudes and displacement continuity was minimized using DP to obtain the displacement map. In this work, we present a novel hybrid method for calculating the displacement map between two ultrasound images. The method uses DP in the first step...
The objective of this paper is to predict the ultrasonic field radiated by piezoelectric transducers with finite dimensions in an isotropic plate. This prediction allows a good understanding of physical phenomenon of Lamb wave propagation used on the Integrated Structural Health Monitoring System. In order to describe correctly the radiated field, the stress field in the length direction of the transducer...
Ultrasound imaging relies heavily on the skills of the sonographer, requiring extensive hands-on training. The Interactive Training System for Medical Ultrasound is an inexpensive, software-based training system, in which the trainee scans a lifelike manikin using a sham transducer, containing a 6 degree of freedom (DoF) tracking sensor. The observed ultrasound image is generated from a pre-stored...
We report on several successful examples of using finite elements based software package for modeling SAW structures with dimensions above 100 wavelengths in the propagation direction including all the electrodes and spaces. The approach easily incorporates additional layers and elements with arbitrary 3D shapes that are common in SAW devices. Temperature behavior of the frequency response, SAW beam...
In this paper, we extend a computationally efficient framework for tracking of deformable subdivision surfaces in 3D echocardiography with speckle-tracking measurements to track material points. Tracking is performed in a sequential state-estimation fashion, using an extended Kalman filter to update a subdivision surface in a two-step process: Edge-detection is first performed to update the model...
In this paper, we present an extension of a computationally efficient Kalman filter based tracking framework to allow simultaneous tracking of several deformable models in volumetric data. The models are coupled through shared transform nodes in a hierarchical structure to enforce common position, orientation and scaling, but are allowed to alter shape independently. Automatic tracking of the endo-...
Mouse cardiac ultrasound imaging is generally acquired as sets of 2D B-mode video or RF data. The high signal bandwidth and frame rate (>100 Hz) required for real-time 3D mouse heart scanning presents a major challenge making it unlikely that direct capture of finely sampled real-time 3D data will be achieved in the near future. Collecting and registering image sets from intersecting orthogonal...
Simulation of ultrasound data is often performed for developing new ultrasound data processing techniques. The spatial impulse response method (as implemented in FieldII) has typically been used as the gold standard due to its excellent accuracy in the linear domain. When scatterer numbers become significant and when 3D volumetric data sets need to be computed, calculation times can become an issue...
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