Book of Abstracts 15th International Symposium on Computer Methods in Biomechanics and Biomedical Engineering and 3rd Conference on Imaging and Visualization

In this edition, the two events will run together as a single conference, highlighting the strong connection with the Taylor & Francis journals: Computer Methods in Biomechanics and Biomedical Engineering (John Middleton and Christopher Jacobs, Eds.) and Computer Methods in Biomechanics and Biomedical Engineering: Imaging and Visualization (JoãoManuel R.S. Tavares, Ed.). The conference has become a major international meeting on computational biomechanics, imaging andvisualization. In this edition, the main program includes 212 presentations. In addition, sixteen renowned researchers will give plenary keynotes, addressing current challenges in computational biomechanics and biomedical imaging. In Lisbon, for the first time, a session dedicated to award the winner of the Best Paper in CMBBE Journal will take place. We believe that CMBBE2018 will have a strong impact on the development of computational biomechanics and biomedical imaging and visualization, identifying emerging areas of research and promoting the collaboration and networking between participants. This impact is evidenced through the well-known research groups, commercial companies and scientific organizations, who continue to support and sponsor the CMBBE meeting series. In fact, the conference is enriched with five workshops on specific scientific topics and commercial software.info:eu-repo/semantics/draf

An Image Based Vibration Sensor for Soft Tissue Modal Analysis in a Digital Image Elasto Tomography (DIET) System

Digital Image Elasto Tomography (DIET) is a non-invasive elastographic breast cancer screening technology, relying on image-based measurement of surface vibrations induced on a breast by mechanical actuation. Knowledge of frequency response characteristics of a breast prior to imaging is critical to maximize the imaging signal and diagnostic capability of the system. A non-invasive image based modal analysis system that is designed to be able to robustly and rapidly identify resonant frequencies in soft tissue is presented in this thesis. A feasibility analysis reveals that three images per oscillation cycle are sufficient to capture the relative motion behavior at a given frequency. Moreover, the analysis suggests that 2D motion analysis is able to give an accurate estimation of the response at a particular frequency. Thus, a sweep over critical frequency ranges can be performed prior to imaging to determine critical imaging settings of the DIET system to maximize diagnositc performance. Based on feasibility simulations, a modal analysis system is presented that is based on the existing DIET digital imaging system. A frequency spectrum plot that comprises responses gathered from more than 30 different frequencies can be obtained in about 6 minutes. Preliminary results obtained from both phantom and human trials indicate that distinctive resonant frequencies can be obtained with the modal analysis system. Due to inhomogeneous properties of human breast tissues, different imaging location appear to pick up different resonances. However, there has been very limited clinical data for validating such behavior. Overall, a modal analysis system for soft tissue has been developed in this thesis. The system was first evaluated in simulation, then implemented in hardware and software, and finally successfully validated in silicone phantoms as well as human breasts

Simulation study on acousto-optics sensing of focused ultrasound

Abstract. The acousto-optics (AO) technique can provide a good contrast with high penetration depth (up to 5 cm) and can be potentially utilized in real time monitoring of the focused ultrasound (FUS) therapies. This work presents the AO simulation study on the interaction of light and FUS in the single-layer brain (SLB) medium and four-layer brain (FLB) medium. FUS pressure distribution at 0.5 MHz and 0.9 MHz frequency was simulated on k-Wave toolbox and the AO Monte Carlo (MC) algorithm was developed on MATLAB to simulate the AO effect in both mediums. The result for the SLB for both ultrasound (US) frequencies suggests that the modulation depth (MD) is high in the region of US focus with a magnitude of 2%-3% and <1% at 0.5 MHz and 0.9 MHz, respectively. Moreover, the MD decreases to 5 orders of magnitude at the source region. In the FLB, the MD decreased to 4–4.5 orders at the source and was present in the skull and US focus region with a magnitude of <1% at both US frequencies. These results suggest that AO can be utilized in sensing FUS effects on brain tissue and the AO signal-to-noise ratio (SNR) depends not only on the MD but also on the level of light intensity interacting with the US pressure

Neurosurgery and brain shift: review of the state of the art and main contributions of robotics

Este artículo presenta una revisión acerca de la neurocirugía, los asistentes robóticos en este tipo de procedimiento, y el tratamiento que se le da al problema del desplazamiento que sufre el tejido cerebral, incluyendo las técnicas para la obtención de imágenes médicas. Se abarca de manera especial el fenómeno del desplazamiento cerebral, comúnmente conocido como brain shift, el cual causa pérdida de referencia entre las imágenes preoperatorias y los volúmenes a tratar durante la cirugía guiada por imágenes médicas. Hipotéticamente, con la predicción y corrección del brain shift sobre el sistema de neuronavegación, se podrían planear y seguir trayectorias de mínima invasión, lo que conllevaría a minimizar el daño a los tejidos funcionales y posiblemente a reducir la morbilidad y mortalidad en estos delicados y exigentes procedimientos médicos, como por ejemplo, en la extirpación de un tumor cerebral. Se mencionan también otros inconvenientes asociados a la neurocirugía y se muestra cómo los sistemas robotizados han ayudado a solventar esta problemática. Finalmente se ponen en relieve las perspectivas futuras de esta rama de la medicina, la cual desde muchas disciplinas busca tratar las dolencias del principal órgano del ser humano.This paper presents a review about neurosurgery, robotic assistants in this type of procedure, and the approach to the problem of brain tissue displacement, including techniques for obtaining medical images. It is especially focused on the phenomenon of brain displacement, commonly known as brain shift, which causes a loss of reference between the preoperative images and the volumes to be treated during image-guided surgery. Hypothetically, with brain shift prediction and correction for the neuronavigation system, minimal invasion trajectories could be planned and shortened. This would reduce damage to functional tissues and possibly lower the morbidity and mortality in delicate and demanding medical procedures such as the removal of a brain tumor. This paper also mentions other issues associated with neurosurgery and shows the way robotized systems have helped solve these problems. Finally, it highlights the future perspectives of neurosurgery, a branch of medicine that seeks to treat the ailments of the main organ of the human body from the perspective of many disciplines

Multiscale mechano-morphology of soft tissues : a computational study with applications to cancer diagnosis and treatment

Cooperation of engineering and biomedical sciences has produced significant advances in healthcare technology. In particular, computational modelling has led to a faster development and improvement of diagnostic and treatment techniques since it allows exploring multiple scenarios without additional complexity and cost associated to the traditional trial-and-error methodologies. The goal of this thesis is to propose computational methodologies to analyse how the changes in the microstructure of soft tissues, caused by different pathological conditions, influence the mechanical properties at higher length scales and, more importantly, to detect such changes for the purpose of quantitative diagnosis and treatment of such pathologies in the scenario of drug delivery. To achieve this objective different techniques based on quasi-static and dynamic probing have been established to perform quantitative tissue diagnosis at the microscopic (tissue) and macroscopic (organ) scales. The effects of pathologies not only affect the mechanical properties of tissue (e.g. elasticity and viscoelasticity), but also the transport properties (e.g. diffusivity) in the case of drug delivery. Such transport properties are further considered for a novel multi-scale, patient-specific framework to predict the efficacy of chemotherapy in soft tissues. It is hoped that this work will pave the road towards non-invasive palpation techniques for early diagnosis and optimised drug delivery strategies to improve the life quality of patientsJames-Watt Scholarship, Heriot-Watt Annual Fund and the Institute of Mechanical, Process and Energy Engineering (IMPEE) Grant

Modulography: elasticity imaging of atherosclerotic plaques

Modulography is an experimental elasticity imaging method. It has potential to become an all-in-one in vivo tool (a) for detecting vulnerable atherosclerotic coronary plaques, (b) for assessing information related to their rupture-proneness and (c) for imaging their elastic material composition. Modulography determines a cross-sectional image of the elasticity distribution (=Young's modulus) from deformation (=strain) that is processed from intravascular ultrasound (IVUS) measurements. By looking at this image, cardiologists and other researchers can directly identify and characterize soft and stiff plaque-components of thin-cap fibroatheromas and of heterogeneous plaques. As a diagnostic and pharm

Digital Image Elasto-Tomography: Mechanical Property Reconstruction from Surface Measured Displacement Data

Interest in elastographic techniques for soft tissue imaging has grown as relevant research continues to indicate a correlation between tissue histology and mechanical stiffness. Digital Image Elasto-Tomography (DIET) presents a novel method for identifying cancerous lesions via a three-dimensional image of elastic properties. Stiffness reconstruction with DIET takes steady-state motion captured with a digital camera array as the input to an elastic property reconstruction algorithm, where finite element methods allow simulation of phantom motion at a range of internal stiffness distributions. The low cost and high image contrast achievable with a DIET system may be particularly suited to breast cancer screening, where traditional modalities such as mammography have issues with limited sensitivity and patient discomfort. Proof of concept studies performed on simulated data sets confirmed the potential of the DIET technique, leading to the development of an experimental apparatus for surface motion capture from a range of soft tissue approximating phantoms. Error studies performed on experimental data from these phantoms using a limited number of shape and modulus parameters indicated that accurate measurements of surface motion provide sufficient information to identify a stiffness distribution in both homogeneous and heterogeneous cases. The elastic reconstruction performed on simulated and experimental data considered both deterministic and stochastic algorithms, with a combination of the two approaches found to give the most accurate results, for a realistic increase in computational cost. The reconstruction algorithm developed has the ability to successfully resolve a hard spherical inclusion within a soft phantom, and in addition demonstrated promise in reconstructing the correct stiffness distribution when no inclusion is present