Patient-Specific Virtual Insertion of Electrode Array for Electrical Simulations of Cochlear Implants

International audienceSensorineural hearing loss is becoming one the most common reasons of disability. Worldwide 278 million people (around 25% of people above 45 years) suffer from moderate to several hearing disorders. Cochlear implantation (CI) enables to convert sound to an electrical signal that directly stimulates the auditory nerves via the electrode array surgically placed. However, this technique is intrinsically patient-dependent and its range of outcomes is very broad. A major source of outcome variability resides in the electrode array insertion. It has been reported to be one of the most important steps in cochlear implant surgery. In this context, we propose a method for patient-specific virtual electrode insertion further used into a finite element electrical simulation, and consequently improving the planning of the surgical implantation. The anatomical parameters involved in the electrode insertion such as the curvature and the number of turns of the cochlea, make virtual insertion highly challenging. Moreover, the influence of the insertion parameters and the use of different manufactured electrode arrays increase the range of scenarios to be considered for the implantation of a given patient. To this end, the method we propose is fast, easily parameterizable and applicable to a wide range of anatomies and insertion configurations. Our method is novel for targeting automatic virtual electrode insertion. Also, it combines high-resolution imaging techniques and clinical data to be further used into a finite element study and predict implantation outcomes in humans

The ALICE Silicon Pixel Detector Control system and online calibration tools

The ALICE Silicon Pixel Detector (SPD) contains nearly 107 hybrid pixel cells. The operation of the SPD requires online control and monitoring of some 2000 parameters and » 50000DACs. Information for each channel is stored in a configuration database. Timing and data management (» 6GB of raw data each calibration) are critical issues. An overview of the SPD electronics read out chain and of the detector control system is given with a detailed description of the front-end controls and the calibration strategy. The status of commissioning and a preliminary evaluation of detector performance are presented

Empresas recuperadas y elaboración de alimentos

La producción de alimentos bromatológicamente apta es uno de los reaseguros para la perdurabilidad de una empresa. El objetivo general es apoyar el derecho de los trabajadores a luchar por su fuente de trabajo y acompañar los procedimientos para asegurar la producción. Si se tiene el conocimiento, se puede tener el control directo del cumplimiento de leyes, códigos y normas. Se pretende un diálogo horizontal, un aprendizaje mutuo entre la sabiduría de las organizaciones sociales que han logrado empoderarse y conseguir, a través de una empresa recuperada, dignidad y autoestima, con un conocimiento bromatológico preventivo y promocional. Uno de los problemas más acuciantes que tienen las empresas recuperadas son las actas y amenaza de clausura de los Municipios por incumplimiento de normas. El monitoreo, evaluación e indicadores de resultados del proyecto podría ser lograr que se suspendan las medidas y construir un plan de mejoras junto a los actores de las organizaciones sociales, para que sea aceptado por los Municipios. Es un desafío importante ya que para los trabajadores de las empresas recuperadas, las normas bromatológicas están muy lejos en sus prioridades. Sin embargo, si el Municipio los clausura sería muy difícil remontar nuevamente toda la documentación, con las inspecciones. Cuando comenzamos con el proyecto fue difícil entablar un diálogo basado en la confianza, primero tuvimos que ganarnos su estima y respeto para que nos confíen sus problemas. Luego encontramos un Municipio muy escéptico, que se había cansado de poner plazos sin encontrar respuesta. Buscamos desarrollar en las personas que trabajan en las empresas recuperadas, un proceso de valoración de los saberes que ellos poseen y lograr que el mecanismo normativo vigente, coopere en su adecuación, con principios basados en una lógica más inclusiva y educadora que disciplinadora. Poner en marcha estos emprendimientos fueron acciones de vanguardia, no responden al modelo positivo dominante de la administración burocrática de los municipios. Hace falta un Estado que se adapte al requerimiento de una economía más social y solidaria y que simboliza una verdadera alternativa productiva ante el empobrecedor modelo neoliberal y un ejemplo que surge de la mano de los trabajadores, mostrando caminos posibles para recuperar su fuente de trabajo y por ende, su dignidad

Automatic Generation of a Computational Model for Monopolar Stimulation of Cochlear Implants

International audienceCochlear implants have the potential to significantly improve severe sensorineural hearing loss. However, the outcome of this technique is highly variable and depends on patient-specific factors. We previously proposed a method for patient-specific electrical simulation after CI, which can assist in surgical planning of the CI and determination of the electrical stimulation pattern. However, the virtual implant placement and mesh generation were carried out manually and the process was not easily applied automatically for further cochlear anatomies. Moreover, in order to optimize the implant designs, it is important to develop a way to stimulate the results of the implantation in a population of virtual patients. In this work we propose an automatic framework for patient-specific electrical simulation in CI surgery. To the best of our knowledge, this is the first method proposed for patient-specific generation of hearing models which combines high-resolution imaging techniques, clinical CT data and virtual electrode insertion. Furthermore, we show that it is possible to use the computational models of virtual patients to simulate the results of the electrical activation of the implant in the cochlea and surrounding bone. This is an important step because it allows us to advance towards a complete surgical planning and implant optimization procedure

The ALICE silicon pixel detector read-out electronics

The ALICE silicon pixel detector (SPD) constitutes the two innermost layers of the ALICE inner tracker system. The SPD contains 10 million pixels segmented in 120 detector modules (half staves), which are connected to the offdetector electronics with bidirectional optical links. Raw data from the on-detector electronics are sent to 20 FPGA-based processor cards (Routers) each carrying three 2-channel linkreceiver daughter-cards. The routers process the data and send them to the ALICE DAQ system via the ALICE detector data link (DDL). The SPD control, configuration and data monitoring is performed via the VME interface of the routers. This paper describes the detector readout and control via the off-detector electronics

Performance of ALICE pixel prototypes in high energy beams

The two innermost layers of the ALICE inner tracking system are instrumented with silicon pixel detectors. Single chip assembly prototypes of the ALICE pixels have been tested in high energy particle beams at the CERN SPS. Detection efficiency and spatial precision have been studied as a function of the threshold and the track incidence angle. The experimental method, data analysis and main results are presented.Comment: 10 pages, 9 figures, contribution to PIX2005 Workshop, Bonn (Germany), 5-8 September 200

Beam Test Performance and Simulation of Prototypes for the ALICE Silicon Pixel Detector

The silicon pixel detector (SPD) of the ALICE experiment in preparation at the Large Hadron Collider (LHC) at CERN is designed to provide the precise vertex reconstruction needed for measuring heavy flavor production in heavy ion collisions at very high energies and high multiplicity. The SPD forms the innermost part of the Inner Tracking System (ITS) which also includes silicon drift and silicon strip detectors. Single assembly prototypes of the ALICE SPD have been tested at the CERN SPS using high energy proton/pion beams in 2002 and 2003. We report on the experimental determination of the spatial precision. We also report on the first combined beam test with prototypes of the other ITS silicon detector technologies at the CERN SPS in November 2004. The issue of SPD simulation is briefly discussed.Comment: 4 pages, 5 figures, prepared for proceedings of 7th International Position Sensitive Detectors Conference, Liverpool, Sept. 200

Trauma coagulopathy and its outcomes

Background and Objectives: Trauma coagulopathy begins at the moment of trauma. This study investigated whether coagulopathy upon arrival in the emergency room (ER) is correlated with increased hemotransfusion requirement, more hemodynamic instability, more severe anatomical damage, a greater need for hospitalization, and hospitalization in the intensive care unit (ICU). We also analyzed whether trauma coagulopathy is correlated with unfavorable indices, such as acidemia, lactate increase, and base excess (BE) increase. Material and Methods: We conducted a prospective, monocentric, observational study of all patients (n = 503) referred to the Department of Emergency and Acceptance, IRCCS Fondazione Policlinico San Matteo, Pavia, for major trauma from 1 January 2018 to 30 January 2019. Results: Of the 503 patients, 204 had trauma coagulopathy (group 1), whereas 299 patients (group 2) did not. Group 1 had a higher hemotransfusion rate than group 2. In group 1, 15% of patients showed hemodynamic instability compared with only 8% of group 2. The shock index (SI) distribution was worse in group 1 than in group 2. Group 1 was more often hypotensive, tachycardic, and with low oxygen saturation, and had a more severe injury severity score than group 2. In addition, 47% of group 1 had three or more body districts involved compared with 23% of group 2. The hospitalization rate was higher in group 1 than in group 2 (76% vs. 58%). The length of hospitalization was >10 days for 45% of group 1 compared with 28% of group 2. The hospitalization rate in the ICU was higher in group 1 than in group 2 (22% vs. 14.8%). The average duration of ICU hospitalization was longer in group 1 than in group 2 (12.5 vs. 9.78 days). Mortality was higher in group 1 than in group 2 (3.92% vs. 0.98%). Group 1 more often had acidemia and high lactates than group 2. Group 1 also more often had BE <−6. Conclusions: Trauma coagulopathy patients, upon arrival in the ER, have greater hemotransfusion (p = 0.016) requirements and need hospitalization (p = 0.032) more frequently than patients without trauma coagulopathy. Trauma coagulopathy seems to be more present in patients with a higher injury severity score (ISS) (p = 0.000) and a greater number of anatomical districts involved (p = 0.000). Head trauma (p = 0.000) and abdominal trauma (p = 0.057) seem related to the development of trauma coagulopathy. Males seem more exposed than females in developing trauma coagulopathy (p = 0.018). Upon arrival in the ER, the presence of tachycardia or alteration of SI and its derivatives can allow early detection of patients with trauma coagulopathy