
Fernando Silva de MouraFederal University of ABC | UFABC · Department of Biomedical Engineering
Fernando Silva de Moura
Doctor of Philosophy
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483
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Publications
Publications (48)
Time-Difference Electrical Impedance Tomography (TDEIT) is an imaging technique to visualize resistivity changes over time in a region of interest. Regularization is necessary because TDEIT is an ill-posed problem. In this work, we use Regularization by Denoising (RED) with four different denoisers to reconstruct brain images in a simplified 2D hea...
Electrical Impedance Tomography (EIT) is an imaging modality that allows the visualization of internal resistivities of a region of interest from electrical measurements external to the same region. In this work, we reconstruct 3D static images using two regularization terms, an anatomical atlas with \(\ell _1\)-norm and a total variation (TV) term...
Electrical impedance tomography (EIT) is a medical imaging modality that has the potential to benefit diagnosing, monitoring, and understanding several pathological conditions. However, some regions of the body, such as the brain, are more challenging to reconstruct, demanding improvements before the technique can be used in clinical practice. In t...
EIT is a non-invasive imaging technique that estimates the distribution of electrical resistivity within the body. This is done by using electrical potential measurements taken on the skin which are induced by a sinusoidal current source. One of the preprocessing steps of the sampled sinusoid—necessary to feed the image estimation algorithm—is the...
Objective. This study focuses on the effects of dynamical vascular modeling on source localization errors in electroencephalography (EEG). Our aim of this in silico study is to (a) find out the effects of cerebral circulation on the accuracy of EEG source localization estimates, and (b) evaluate its relevance with respect to measurement noise and i...
Electrical impedance tomography (EIT) is a technique that can be used to estimate resistivity distribution from the inside of a domain based on surface measurements. This could be useful, for example, in the diagnosis of cerebral strokes. However, a method to acquire EIT images of the head with enough quality to achieve this task is still needed. I...
Continuous monitoring of brain hemodynamics is important to quickly detect changes in healthy cerebral blood flow, helping physician decision-making in the treatment of the patient. Resistivity changes in the brain happen as a result of the pulsatile characteristic of the blood in the arteries or pathological conditions such as ischemia. We develop...
IntroductionAcute ischemic stroke is one of the leading causes of disability globally, requiring the best-integrated approach between prevention, intervention, and therapies aiming to avoid the worse outcome scenario. A careful analysis of potential clinical predictors after stroke under the current data science paradigms can significantly improve...
Cerebral Autoregulation (CA) is a intrinsic mechanism of the brain responsible for maintaining constant cerebral blood flow (CBF) despite the variation in arterial blood pressure (ABP). Transfer function analysis (TFA) is one of the most used signal processing techniques proposed to quantify this ABP-CBF relationship, by using spontaneous ABP oscil...
Alveolar recruitment maneuver is usually applied as part of the treatment of acute respiratory distress syndrome, consisting of a transitory and controlled increase in mechanical ventilator pressure delivered to the patient in order to promote opening of collapsed alveoli. Knowing alveolar recruitment potential may help prevent overdistention durin...
Objective. The objective of this work is to develop a 4D (3D+T) statistical anatomical atlas of the electrical properties of the upper part of the human head for cerebral electrophysiology and bioimpedance applications. Approach. The atlas was constructed based on 3D magnetic resonance images (MRI) of 107 human individuals and comprises the electri...
Volume conductor problems in cerebral electrophysiology and bioimpedance do not have analytical solutions for nontrivial geometries and require a 3D model of the head and its electrical properties for solving the associated PDEs numerically. Ideally, the model should be made with patient-specific information. In clinical practice, this is not alway...
Objective: The purpose of this article is to introduce the readers to the concept and structure of CAAos (Cerebral Autoregulation Assessment Open Source) platform, and provide evidence of its functionality. Approach: CAAos platform is a new open-source software research tool, developed in Python 3 language, that combines existing and novel methods...
The photographic dataset collected for the Helsinki Deblur Challenge 2021 (HDC2021) contains pairs of images taken by two identical cameras of the same target but with different conditions. One camera is always in focus and produces sharp and low-noise images the other camera produces blurred and noisy images as it is gradually more and more out of...
Objective
A pragmatic tool for the early and reliable prediction of recovery in patients with acute ischemic stroke is needed. We aimed to test the addition of brain eloquent areas involvement in variables predicting poor outcome, using a simple scoring system.
Methods
Retrospective study of patients with anterior circulation acute ischemic stroke...
Recent improvements in computational tools opened the possibility of patient-specific modeling to aid clinicians during diagnosis, treatment, and monitoring. One example is the modeling of blood flow for surgical planning, where modeling can help predict the prognosis. Computational analysis is used to extract hemodynamic information about the case...
Background
Treatment of intracranial aneurysms with flow diverter stent (FDS) procedures can lead to caliber changes of jailed vessels. The reason some branches remain unchanged and others are affected by narrowing remains unknown.
Objective
To investigate the influence of resistance to flow from distal vasculature on stent-induced hemodynamic mod...
Electrical Impedance Tomography (EIT) is under fast development. The present paper is a review of some procedures that have contributed to improve spatial resolution and material properties accuracy, admitivity or impeditivity accuracy. A review of EIT medical applications is presented and they were classified into three broad categories: ARDS pati...
Cerebral vasospasm (CVS) is a life-threatening condition that occurs in a large proportion of those affected by subarachnoid haemorrhage and stroke. CVS manifests itself as the progressive narrowing of intracranial arteries. It is usually diagnosed using Doppler ultrasound, which quantifies blood velocity changes in the affected vessels, but has lo...
The design and performance of the active complex electrode (ACE1) electrical impedance tomography system for single-ended phasic voltage measurements are presented. The design of the hardware and calibration procedures allows for reconstruction of conductivity and permittivity images. Phase measurement is achieved with the ACE1 active electrode cir...
Introduction: Eloquent areas of brain have been identified more precisely using functional MRI but not often applied for stroke patients. Furthermore, it is widely accepted that stoke outcome depends on a number of factor including age, stroke lateralization, baseline NIHSS and brain imaging. This study aims to develop a new deconvolution algorithm...
Background and purpose:
Treatment of intracranial bifurcation aneurysms with flow-diverter stents can lead to caliber changes of the distal vessels in a subacute phase. This study aims to evaluate whether local anatomy and flow disruption induced by flow-diverter stents are associated with vessel caliber changes in intracranial bifurcations.
Mate...
This work presents a friendly interface for processing and analyzing myoelectric signals aiming to control upper limb prosthesis using Myo ® armband, a low cost gesture control device. In such framework, an easily-operated pattern recognition system is made available, being capable of displaying raw myoelectric signals, extracting their features (e...
Computational fluid dynamic (CFD) simulations can have a predictive, albeit complementary role alongside established imaging techniques. A significant barrier to the widespread clinical use of CFD models is the lack of validation against real-world data. Although imaging techniques, such as 4D Phase Contrast Magnetic Resonance can provide 3D flow m...
The Electrical Impedance Tomography (EIT) reconstruction problem can be solved as an optimization problem in which the discrepancy between a simulated impedance domain and the observed one is minimized. This optimization problem can be solved by a combination of Simulated Annealing (SA) for optimization and the Finite Element Method (FEM) for simul...
Electrical Impedance Tomography (EIT) is a non-invasive image reconstruction technique, whereby current is injected by electrodes and electric potential is measured by electrodes. In some electronic hardware implementations, only two electrodes inject current simultaneously, and are denominated pair-wise current injection. Several possibilities of...
This paper presents a description of an architecture of an EIT hardware for research. Both, hardware and software for capturing and processing of the EIT signals are addressed. The system is divided in modules with defined requirements and connections, therefore, different implementations are possible. Details of an implementation conceived to vali...
Electrical Impedance Tomography (EIT) is a technique which can image the varying electrical properties of biological tissues. For clinical use of EIT, it can be advantageous to know both tissue conductivity and permittivity. Presented is the hardware design for the pairwise current injection active complex electrode (ACE1) EIT system which measures...
Dynamically monitoring muscle contraction is an important task in sports training and rehabilitation programs. Internal muscles monitoring are specially challenging because they cannot be accessed by palpation or surface EMG. It is well known that blood flow through skeletal muscle can increase 15- to 25-fold during extreme exercise compared to its...
Electrical Impedance Tomography is a non invasive medical imaging technique used to infer living tissue impeditivity from surface electrical measurements. Mathematically this is a ill-posed non-linear inverse problem. An anatomical atlas based on the resistivity of the tissue can be used as a regularization metgod for solving the inverse problem.
C...
Electrical Impedance Tomography (EIT) is a non-invasive method employed to estimate electrical impeditivity distribution maps of internal structures and tissues in vivo. Electrical impeditivity in living tissues is a function, among other factors, of the number of available charge carriers (ions). It is well known that muscle in the anaerobic regim...
One of the electrical impedance tomography objectives is to estimate the electrical resistivity distribution in a domain based only on electrical potential measurements at its boundary generated by an imposed electrical current distribution into the boundary. One of the methods used in dynamic estimation is the Kalman filter. In biomedical applicat...
One of the electrical impedance tomography objectives is to estimate the electrical resistivity distribution in a domain based only on electrical potential measurements at its boundary generated by an imposed electrical current distribution into the boundary. One of the methods used in dynamic estimation is the Kalman filter. In biomedical applicat...
One of the electrical impedance tomography objectives is to estimate the electrical resistivity distribution in a domain based only on contour electrical potential measurements caused by an imposed electrical current distribution into the boundary. In biomedical applications, the random walk model is frequently used as evolution model and, under th...
Electrical Impedance Tomography (EIT) seeks to recover the impedance distribution within a body using boundary data. More specifically, given the measured potentials, the model of the body - an elliptic partial differential equation - and the boundary conditions, this technique solves a non-linear inverse problem for the unknown impedance. In this...
One of the objectives of Electrical Impedance Tomography (EIT) is to estimate the resistivity distribution based on mea- surements of electric potential on the boundaries of a domain,of interest. In this work we propose an algorithm that identifies directly the back-projection matrix given known,perturbations of the resistivity distribution and the...
2. Methods The experimental data was collected from the boundary of a human chest during normal breathing. The volunteer was upright during data collection, quietly breathing. The dynamics of ventilation and perfusion inside the thorax was represented by a second order homogeneous set of ordinary differential equations (ODEs). The size of the state...
Electrical Impedance Tomography estimates the impedance distribution of a domain of interest. The Sheffield back-projection algorithm for Electrical Impedance Tomography uses an interpolation method to increase the number of potential measurements on the boundary and consequently improving the image resolution. Santosa and Vogelius suggest using a...
Resumo — Uma das aplica oes da Tomografia de Impedância Elétrica (TIE e a monitora ao contínua e não invasiva do estado dos pulmões. Para tal, o tomógrafo utiliza medidas elétricas (corrente ou voltagem) na fronteira do domínio a ser estudado para a reconstru ao de imagens médicas. Um dos algoritmos utilizados para taí e o de backprojection, que es...