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

Cell reorientation under cyclic stretching

Mechanical cues from the extracellular microenvironment play a central role in regulating the structure, function and fate of living cells. Nevertheless, the precise nature of the mechanisms and processes underlying this crucial cellular mechanosensitivity remains a fundamental open problem. Here we provide a novel framework for addressing cellular sensitivity and response to external forces by experimentally and theoretically studying one of its most striking manifestations -- cell reorientation to a uniform angle in response to cyclic stretching of the underlying substrate. We first show that existing approaches are incompatible with our extensive measurements of cell reorientation. We then propose a fundamentally new theory that shows that dissipative relaxation of the cell's passively-stored, two-dimensional, elastic energy to its minimum actively drives the reorientation process. Our theory is in excellent quantitative agreement with the complete temporal reorientation dynamics of individual cells, measured over a wide range of experimental conditions, thus elucidating a basic aspect of mechanosensitivity.Comment: For supplementary materials, see http://www.nature.com/ncomms/2014/140530/ncomms4938/extref/ncomms4938-s1.pd

Sistema no invasivo para la medida y visualización de desplazamientos de tejidos en neurocirugía

[ES] Se presenta un sistema de imagen médica basado en medición de distancias entre tejidos por medio de microondas. El sistema está pensado para la monitorización y corrección del problema de brain-shift en operaciones de tumores cerebrales. Se muestra el sistema desarrollado y los primeros resultados con phantoms de tejidos cerebrales que tienen una morfología similar a los tejidos reales. Se demuestra la viabilidad del sistema para la medida de distancias y la reconstrucción de una imagen 3D intraoperatoria.[EN] A medical imaging system based on measuring distances between tissues by means of microwaves is presented. The system is designed for the monitoring and correction of the brain-shift problem in brain tumor operations. It shows the developed system and the first results with phantoms of brain tissues that have a morphology similar to real tissues. The viability of the system for the measurement of distances and the reconstruction of an intraoperative 3D image is demonstrated.Juan, C.; Blanco, C.; Herrero, N.; Garcia, H.; Vicente-Samper, J.; Avila, E.; Sabater-Navarro, J. (2019). Sistema no invasivo para la medida y visualización de desplazamientos de tejidos en neurocirugía. En 11º Simposio CEA de Bioingeniería. Editorial Universitat Politècnica de València. 76-84. https://doi.org/10.4995/CEABioIng.2019.10033OCS768

Intraoperative Imaging Modalities and Compensation for Brain Shift in Tumor Resection Surgery

Intraoperative brain shift during neurosurgical procedures is a well-known phenomenon caused by gravity, tissue manipulation, tumor size, loss of cerebrospinal fluid (CSF), and use of medication. For the use of image-guided systems, this phenomenon greatly affects the accuracy of the guidance. During the last several decades, researchers have investigated how to overcome this problem. The purpose of this paper is to present a review of publications concerning different aspects of intraoperative brain shift especially in a tumor resection surgery such as intraoperative imaging systems, quantification, measurement, modeling, and registration techniques. Clinical experience of using intraoperative imaging modalities, details about registration, and modeling methods in connection with brain shift in tumor resection surgery are the focuses of this review. In total, 126 papers regarding this topic are analyzed in a comprehensive summary and are categorized according to fourteen criteria. The result of the categorization is presented in an interactive web tool. The consequences from the categorization and trends in the future are discussed at the end of this work

Sistema multimodal para medir el desplazamiento cerebral intraoperatorio en tiempo real

Programa de Doctorado en Tecnologías Industriales y de TelecomunicaciónLa neurocirugía robótica está sufriendo profundos cambios en los últimos tiempos, fruto principalmente de los avances en las técnicas de imagen médica (TAC, RM, RMf o DTI), lo que permite una mejor planificación de la operación a realizar. La neurocirugía mínimamente invasiva se ve beneficiada de estos avances. Sin embargo, quedan problemas a resolver en la transferencia del plan de trabajo preplanificado a la realidad intraoperatoria, debido a la naturaleza no lineal de los tejidos deformables involucrados. Uno de estos problemas es el brain shift, o desplazamiento de la materia cerebral producto del cambio de presión interior al practicar la craneotomía y de los propios procesos quirúrgicos, que producen una pérdida de referencia de los volúmenes de imagen de neurocirugía adquiridos antes de la cirugía. Los quirófanos con RM intraoperatoria han demostrado ser muy caros, y por tanto, poco accesibles para solucionar este problema de pérdida de referencia. Este trabajo de tesis doctoral presenta el desarrollo de un sistema colaborativo intraoperatorio de RA en técnicas de neurocirugía mínimamente invasiva. En concreto, permite visualizar en hologramas 3D el modelo cerebral del paciente con todas las deformaciones que van ocurriendo durante la neurocirugía, en base a la información en tiempo real proporcionada por un nuevo sistema para la medición de distancias de manera no invasiva. Las deformaciones volumétricas sufridas en puntos no visibles del cerebro son obtenidas mediante un conjunto de antenas de microondas y un modelo matemático biomecánico. El aporte de esta tesis doctoral ha sido, por tanto, generar una herramienta para la neurocirugía robótica que permita ayudar a solucionar los actuales problemas de localización derivados del fenómeno del brain shift

Coupled Dictionary Learning for Image Analysis

Modern imaging technologies provide different ways to visualize various objects ranging from molecules in a cell to the tissue of a human body. Images from different imaging modalities reveal distinct information about these objects. Thus a common problem in image analysis is how to relate different information about the objects. For instance, relating protein locations from fluorescence microscopy and the protein structures from electron microscopy. These problems are challenging due to the difficulties in modeling the relationship between the information from different modalities. In this dissertation, a coupled dictionary learning based image analogy method is first introduced to synthesize images in one modality from images in another. As a result, using my method multi-modal registration (for example, registration between correlative microscopy images) is simplified to a mono-modal one. Furthermore, a semi-coupled dictionary learning based framework is proposed to estimate deformations from image appearances. Moreover, a coupled dictionary learning method is explored to capture the relationship between GTPase activations and cell protrusions and retractions. Finally, a probabilistic model is proposed for robust coupled dictionary learning to address learning a coupled dictionary with non-corresponding data. This method discriminates between corresponding and non-corresponding data thereby resulting in a "clean" coupled dictionary by removing non-corresponding data during the learning process.Doctor of Philosoph