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The early detection of biomechanical modifications in the arterial wall could be used as a predictor factor for various diseases, for example hypertension or atherosclerosis. In this work a transient elastography technique is used for the in vitro evaluation of the arterial wall elasticity. The obtained Young modulus is compared with the one obtained by a more classical approach: pressure-diameter...
The acoustic radiation force has been used as the method to examine the physical properties of materials in several areas. Vibro-acoustography is an acoustic radiation force technique that is being used to perform analysis of mechanical properties of materials. In this application a focused acoustic modulated force excites target which vibrates at the frequency of modulation. The emitted sound is...
The initial motivation for this work was to accomplish an easy way to manufacture different geometries of ultrasonic transducers and arrays using a PZT powder, combined with a standard process to have repetitive series of them. The piezoelectric thick film was obtained using a PZT paste and applying it by screen printing on an alumina substrate. Then, the film was drying and sintered with a temperature-time...
Obstructive sleep apnea/hypopnea Syndrome (OSAHS) is the most common form of Sleep Disordered Breathing (SDB) and it is estimated to affect approximately 6% of US adult population. Various methods have been proposed for the development of inexpensive screening methods to detect SDB to reduce the need for costly nocturnal polysomnography (NPSG). By using the existing air in the airway as an ultrasonic...
We have already reported our attempt to constrain direction of microcapsules in flow owing to an acoustic radiation force. However, the diameter of capsules was too large not to be applied in vivo. Furthermore, acoustic radiation force affected only in focal area because focused ultrasound was used. Thus we have improved our experiment by using microcapsules as small as blood cells and introducing...
In patients with gastroesophageal reflux disease (GERD), esophageal symptoms are traditionally diagnosed by monitoring the contact time between the reflux content and the esophagus using multichannel intraluminal impedance and pH (MII-pH) catheters. However, esophageal catheter for quantifying the volume of reflux content is still lacking. The present work proposes an innovative method to develop...
The trabecular bones are highly dispersive acoustic media composed by randomly shaped trabeculae (considered as scatterers) and surrounded by bone marrow. An acoustic wave generated by an incident ultrasonic pulse with respect to the media under study, shows that its velocity and amplitude are a function of the density size and shaped of the scatterers. Two different methods were used to theoretically...
A platform to study ultrasound as a source for wireless energy transfer and communication for implanted medical devices is described. A tank is used as a container for a pair of electroacoustic transducers, where a control unit is fixed to one wall of the tank and a transponder can be manually moved in three axes and rotate using a mechanical system. The tank is filled with water to allow acoustic...
Magnetoacoustic tomography with magnetic induction (MAT-MI) is a recently introduced method for imaging electrical impedance properties, which integrates classic electrical impedance tomography and ultrasonic technique. In this paper, a new method is proposed to avoid the singularity of the divergence of Lorentz force on the interfaces between two kinds of medium. A two-dimensional model was used...
In the present work the ultrasound biomicroscopy (UBM) technique is applied in the study of cutaneous cell carcinomas in vitro, including superficial basal cell carcinomas (BCC) and Bowen disease (BD) cases. The evaluation was made by qualitative observation of UBM images, and by quantitative computation of integrated backscatter coefficient (IBC), obtained with a system working at a central frequency...
Modern ultrasound imaging instrumentation for clinical applications allows real-time volumetric scanning of the patients' body. 4D imaging has been made possible thanks to the development of new echographic probes which consist in 2D phased arrays of piezoelectric transducers. In these new devices it is the system electronics which properly drives the matrix elements and focuses the beam in order...
We report on a microfabricated silicon microprobe integrated with an ultrasonic actuator and polysilicon strain gauges for Microdissection TEsticular Sperm Extraction (TESE) surgery. Multiple microprobe insertion experiments were performed on rat testis tissue and, by monitoring the tubule puncture artifacts in the force signal sensed by the microprobe, we were able to estimate the average diameter...
The goal of this study is to optimize the transfer of acoustic energy deep in the body. In order to find suitable acoustic paths for the energy transfer to be efficient, we propose a model of ultrasound propagation that takes into account a realistic geometry of the tissue layers inside the human body. The data from the Visible Human Project is used to identify the tissues between the transducer array...
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