I. Bazan

Autonomous University of Aguascalientes | UAA · Departamento de Ingeniería Biomédica

The computational modelling and analysis of internal and external temperature distributions and their gradients, associated with the first stage of mammary tumors, was performed to relate thermal parameters to relevant tumor characteristics. A realistic 3D geometric model of breast anatomy was used to simulate tumor cases that were characterized in...

Maintaining the greatest amount of visual field of a glaucoma patient is still a challenge today. It is difficult to diagnose the disease in its early stages, due to the lack of symptoms in many cases. Therefore, in this work, an eyeball model was developed to evaluate the behavior of some anterior segment structures of the eye against slight chang...

The development and integration of an electroencephalographic signal acquisition and stimulation system is proposed to support the detection of pathologies related to the optic nerve. It is based on the extraction and analysis of a characteristic waveform called Visual Evoked Potential immersed in the electroencephalographic register. Some paramete...

In this work, the computational simulation of thermal gradients related to internal lesions according to the phenomenon of pathological angiogenesis is proposed, this is based on the finite element method, and using a three¬dimensional geometric model adjusted to suit the real female anatomy. The simulation of the thermal distribution was based on...

Introduction: In this paper, it is presented an assessment of different windowing techniques and denoising methods applied to detect the Visual Evoked Potential (VEP) contained into the electroencephalographic (EEG) signals. The objective is to analyze advantages and disadvantages of each technique performance to identify correctly the VEP waveform...

In this work, an analysis of the principal characteristics, scientific aims and some initial results, of the Iberoamerican R&D network “Ditecrod” (Project of CYTED) is made. This network is based on an international agreement to propitiate an efficient trans-disciplinary cooperation in a scientific area where currently significant research efforts...

In the recent years, ultrasound has become an inspection tool under investigation to explore laminated biological structures to found mechanical or structural changes related to early stages of diseases. The resolution capability of ultrasound to explore these micro-changes not only depends on the frequency, but also in the processing methods appli...

Bioelectric signals are distorted by unwanted electric noise interference. This paper focuses on techniques that can be applied to surface electromyographic systems design to improve the signal-to-noise ratio. Three case studies are presented in this manuscript: Effects of the front-end instrumentation amplifier gain, use of dc-dc converters for si...

Las herramientas que permiten una inspección del cuerpo humano con mínima invasión, son foco de interés de los investigadores, por esta razón, el ultrasonido funge como uno de los principales protagonistas en este rubro, . En este trabajo se desarrolló el prototipo de una herramienta que permite estimar la impedancia acústica de un medio a partir d...

El presente trabajo describe el diseño e implementación de un sistema no invasivo para el análisis de movimiento conformado por electrogoniometría (EGM) basada en un sensor resistivo y electromiografía (EMG) de superficie, para ser aplicado a futuro en pacientes infantes con discapacidad motriz. El sistema desarrollado cuenta con una interfaz Bluet...

The aim of this work is to develop a new type of ultrasonic analysis of the mechanical properties of an arterial wall with improved resolution, and to confirm its feasibility under laboratory conditions. Motivation: it is expected that this would facilitate a non-invasive path for accurate predictive diagnosis that enables an early detection & th...

Some research results of cooperation works in biomedical engineering, established among current national projects of Mexico and Spain, are resumed. They are related to coordinated activities of three R & D groups, with the aim to achieve high-resolution ultrasonic thermometry into tissue phantoms with internal reflectors of a non-invasive way. Adva...

The detection of changes in the properties of the walls in blood vessels (e.g. modifications in thickness or elasticity) is a promising way for the early diagnosis of cardiovascular diseases (e.g. atherosclerosis), and some attempts have been made using classic ultrasonic images. However, to obtain a reliable non invasive estimation of these change...

In the field of ultrasound transducers to generate frozen rings waves generated a tendency for use in biomedical applications. This paper proposes simulate through Finite Element Method (FEM) simulation of a transducer with 10 rings to find patterns of acoustic field and get a model attached to the real transducer designed by Castellanos et al [3]....

The classical 0-order X-wave is a limited-diffraction solution for the scalar wave equation and provides good beam focusing along a large depth, for instance, in high-resolution ultrasonic imaging. In this work, only the negative-time parts of 0-order X-waves are used like driving signals for a Bessel array in order to produce a highly focused acou...

In this paper the development of a prototype for a myoelectric prosthesis elbow joint is described. It is divided into three parts; the first is the conditioning of the myoelectric signal (SME) which proposed a circuit that is formed by a stage of pre-amplification, followed by a stage of filtering, another stage of amplification and finally a stag...

The objective of this paper is to develop an ultrasound signal processing technique suitable to measure changes in distance between two membranes that simulate the pleural membranes in a basic human thorax phantom. The proposed technique is based on the correlation and autocorrelation methods. Obtaining an accuracy of 96.83 percent compared to thos...

We present a novel procedure that automatically and reliably determines the presence of cardiomegaly in chest image radiographies. The cardiothoracic ratio (CTR) shows the relationship between the size of the heart and the size of the chest. The proposed scheme uses a robust fuzzy classifier to find the correct feature values of chest size, and the...

We propose a three-dimensional Gaussian denoising scheme for application to color video frames. The time is selected as a third dimension. The algorithm is developed using fuzzy rules and directional techniques. A fuzzy parameter is used for characterization of the difference among pixels, based on gradients and angle of deviations, as well as for...

The objective of this paper is to develop ultrasound signal processing techniques suitable to measure changes in distance between two membranes in a basic human thorax phantom. The two proposed techniques are based on correlation and phase analysis, getting an accuracy of 94.93% and 92.60% respectively regarding to the measurements obtained with th...

In this paper, a design of transducer array to implement Biomedical Applications by Acoustics Frozen Waves, such as diathermy, hyperthermia, tissue ablation tissue, is presented. The example shows a method to obtain an optimal space between rings (kerf) for each Fz, based on minimization of RMSE. The results of kerf VS RMSE, for our synthesizing fu...

By locally measuring changes on arterial wall thickness as a function of pressure, the related Young modulus can be evaluated. This physical magnitude has shown to be an important predictive factor for cardiovascular diseases. For evaluating those changes, imaging segmentation or time correlations of ultrasonic echoes, coming from wall interfaces,...

Abstract –– Research looking for the achieving of an accurate measurement of thickness changes in thin biological walls (e.g. of blood vessels), is a promising work line in the medical area, because it would provide the bases to analyze the possibility of attaining early diagnoses of some diseases such as hypertension or atherosclerosis. But, to ob...

The spectral analysis techniques has been widely used to extract information about certain signals and the process in which those are generated. Ultrasonic (US) signal acquired from biological tissues are a particular case of that. Spectral analysis has been used to extract information from US signal related to biological tissue condition, mainly r...

An advanced procedure for Parametric Spectral Analysis (PSA), developed by the authors [1], was applied to three groups of ultrasonic echo-signals acquired from liver tissue of Wistar rats. Each group consisted on multiecho signals acquired from 5 specimens. The first group of signals was acquired from liver of 5 healthy rats, selected as a control...

Achieving accurate measurements of inflammation levels in tissues or thickness changes in biological membranes (e.g., amniotic sac, parietal pleura) and thin biological walls (e.g., blood vessels) from outside the human body, is a promising research line in the medical area. It would provide a technical basis to study the options for early diagnosi...

To achieve a precise noninvasive temperature estimation, inside patient tissues, would open promising research fields, because its clinic results would provide early-diagnosis tools. In fact, detecting changes of thermal origin in ultrasonic echo spectra could be useful as an early complementary indicator of infections, inflammations, or cancer. Bu...

Nowadays new methods of echographic signal processing have emerged to support the medical diagnosis. In the first stage of development, these methods should be assessed with a considerable number of realistic echo-signals. In this paper, a mathematical model of hepatic tissue is proposed. This will be used to generate echo-graphic signals adjusted...

Parametric algorithms previously developed by authors for spectral evaluation of biological multi-echo waveforms are adapted and improved here in order to achieve a more elevated frequency resolution. These results permit to undertake viability studies around the possible application of a new auto-regressive spectral technique to estimate physical...

Paper invitado

In this paper, a quantitative and predictive evaluation is presented, to assess the responses observed in a procedure intended for measuring internal thermal properties, from biological tissues, in a rigorously non-invasive way. A set of multi-echo ultrasonic traces is generated, trying to simulate resulting signal traces from a typical inspection...

This paper proposes and applies a signal processing tool, based on the correlation operator, intended for obtaining approximated solutions of the inversion ultrasonic problem of synthesizing voltage excitations sets in order to form limited diffraction waves, with possible future application for low-cost medical diagnosis. All the calculations anal...

More relevant results in research & technological development achieved in the Dpt. Ultrasonic Signals, Systems & Technologies (CSIC), during the last five years, are commented. They are centered on the Physics and Technology of the Ultrasonic Systems and their associate subject matters, including: modeling, simulation and design of aspects as trans...

The objective of this work is to define the preliminary bases needed for achieving an evaluation of responses of the spectral analysis technique for non invasive temperature estimation, when applied to multi-echo ultrasonic signals contaminated with increasing noise levels. Power Spectral Density (PSD) of an ultrasonic signal is calculated in order...

This work provides a quantitative specific evaluation of the spectral analysis performance when applied to ultrasonic multiecho-signals, in order to extract information from them, for non-invasive temperature estimation purposes, inside a biological tissue. This specific evaluation was oriented to assess the thermal resolution provided by the appli...

An analysis of the accuracy level in different alternative techniques for the estimation of increasing temporal displacements in ultrasonic echoes acquired from phantoms (physical and computationally simulated) that mimic biological tissues, is carried out. These time displacements of echoes can be produced, for instance, by a controlled induction...

Noninvasive thermometry is one of the greatest challenges for hyperthermia treatment and ultrasound thermometry is one of the most attractive techniques used for this purpose. In this chapter, four time-delay estimation methods, which relate temperature changes inside tissue replica (phantom) with time shifts in ultrasound echo-signals, were tested...

An spectral analysis technique, that establishes a linear relation between the temperature changes in a body and the frequency displacement in the overtone peaks being displayed in the power spectral density (PSD) of ultrasonic echo-signal, has been improved and applied by the paper authors to estimate temperature gradients induced inside a biologi...

In this work an analysis of four methods for temporal displacement measurement of ultrasonic echoes is presented, to determine their precision and sensibility to different noise levels, with the main objective to evaluate their potential application on non invasive internal temperature estimation. Procedures and methodologies to perform this analys...

Optimization of efficiency in hyperthermia requires a precise and non-invasive estimation of internal distribution of temperature. Although there are several research trends for ultrasonic temperature estimation, efficient equipments for its use in the clinical practice are not still available. The main objective of this work was to research about...

Noninvasive thermometry is one of the greatest challenges for hyperthermia treatment and ultrasound thermometry is one of the most attractive techniques used for this purpose. In this chapter, four time-delay estimation methods, which relate temperature changes inside tissue replica (phantom) with time shifts in ultrasound echo-signals, were tested...

To simulate the real conditions where the ultrasound will be applied, it is necessary the employment of materials to mimic the ultrasound behavior of tissues; these kind of materials are called phantoms. Therefore, it is important to measure the basic characteristics that must be mimicked; one of them is the ultrasound propagation speed. This chara...

This paper presents a noise immunity analysis of time delay estimation (TDE) techniques used on ultrasonic echoes for non invasive temperature estimation. Four methods are analyzed. The methodology consists on corrupting a simulated ultrasonic signal (ideal signal) with white noise and a signal-to-noise ratio of 3 dB and 6 dB. After this, noise imm...

To dispose of a precise and non-invasive temperature measurement over the treated area becomes very important during hyperthermia treatments, in order to make possible an optimisation of their healing effects. A performance analysis of some previously reported ultrasonic techniques, which were proposed for non-invasive temperature estimation, is ma...

To dispose of a precise and non-invasive temperature measurement over the treated area becomes very important during hyperthermia treatments, in order to make possible an optimization of their healing effects. A performance analysis of some previously reported ultrasonic techniques, which were proposed for non-invasive temperature estimation, is ma...