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Biomedical subjects

F del Pozo

Publications and source records attributed to F del Pozo.

At least 19 recordsLinked to original sources
PubMed2006

Tissue consistency perception in laparoscopy to define the level of fidelity in virtual reality simulation.

BACKGROUND: What degree of fidelity must a laparoscopic simulator have to achieve a training objective? This difficult question is addressed by studying the sensory interaction of surgeons in terms of a surgical skill: tissue consistency perception. METHODS: A method for characterizing surgeon sensory interaction has been defined and applied in an effort to determine the relative importance of three components of perceptual surgical skill: visual cues, haptic information, and previous surgical knowledge and experience. Expert, intermediate, and novel surgeons were enrolled in the study. Users were asked to rank tissue consistency in four different conditions: a description of the tissue alone (Q), visual information alone (VI), tactile information alone (TI), and both visual and tactile information (VTI). Agreement between these stages was assessed by a coefficient of determination (R2). RESULTS: Tissue is a determinant factor (p < 0.001) in the perception of tissue consistency, whereas the expertise of the surgeon is not (p = 0.289). Tissue consistency perception is based mainly on tactile information (TI-VTI agreement is high, R2 = 0.873), although little sensory substitution is present (VI-VTI agreement is low, R2 = 0.509). Agreement of Q-VI increases with experience (R2 = 0.050, 0.290, and 0.573, corresponding with to novel, intermediate, and expert surgeons), which has been associated with the "visual haptics" concept. CONCLUSIONS: Virtual reality simulators need haptic devices with force feedback capability if tissue consistency information is to be delivered. On the other hand, the visual haptics concept has been associated with a kind of tactile memory developed by surgical experience.

Clinical Competence↗
PubMed2006

Integrated care prevents hospitalisations for exacerbations in COPD patients.

Hospital admissions due to chronic obstructive pulmonary disease (COPD) exacerbations have a major impact on the disease evolution and costs. The current authors postulated that a simple and well-standardised, low-intensity integrated care intervention can be effective to prevent such hospitalisations. Therefore, 155 exacerbated COPD patients (17% females) were recruited after hospital discharge from centres in Barcelona (Spain) and Leuven (Belgium). They were randomly assigned to either integrated care (IC; n = 65; age mean+/-sd 70+/-9 yrs; forced expiratory volume in one second (FEV(1)) 1.1+/-0.5 L, 43% predicted) or usual care (UC; n = 90; age 72+/-9 yrs; FEV(1) 1.1+/-0.05 L, 41% pred). The IC intervention consisted of an individually tailored care plan upon discharge shared with the primary care team, as well as accessibility to a specialised nurse case manager through a web-based call centre. After 12 months' follow-up, IC showed a lower hospitalisation rate (1.5+/-2.6 versus 2.1+/-3.1) and a higher percentage of patients without re-admissions (49 versus 31%) than UC without differences in mortality (19 versus 16%, respectively). In conclusion, this trial demonstrates that a standardised integrated care intervention, based on shared care arrangements among different levels of the system with support of information technologies, effectively prevents hospitalisations for exacerbations in chronic obstructive pulmonary disease patients.

Aged↗
PubMed2005

Analysis of information and communication needs in rural primary health care in developing countries.

This article presents three studies dealing with information and communication needs in rural primary health care from Peru and Nicaragua. Results show that primary health-care systems in rural areas of developing countries are very inefficient. Among the main reasons we found factors related to communication infrastructure, information sharing, and continuous training of health professionals. We conclude that telemedicine systems can improve this situation, but the lack of infrastructures, low income levels, and other conditions, impose strong limits to the introduction of new technologies. The main conclusion is that differences in needs and conditions between developing countries and industrialized ones force to use different solutions and approaches. This article presents some proposals on technology requirements and how to deal with the use of telemedicine in rural areas of developing countries. These proposals can be useful to all kind of actors (national public administrations, multilateral institutions, industry, academy, civil society, etc.) in order to promote really relevant and sustainable proposals in telemedicine for rural regions of developing countries.

Developing Countries↗
PubMed2001

Optimisation and evaluation of an asynchronous transfer mode teleradiology co-operative system: the experience of the EMERALD and the BONAPARTE projects.

This paper describes the work carried out to optimise and evaluate in clinical routine a multimedia telemedicine application for co-operative imaging diagnosis. This research has been attained within the framework of two European research projects, namely the EMERALD [1] and the BONAPARTE [2]. A user-centred telemedicine application was developed on an existing advanced broadband multimedia teleradiology platform to exploit the possibilities offered by Asynchronous Transfer Mode (ATM) technology to support real-time teleconsultation services for medical imaging. The evaluation of this telemedicine system in both projects has been performed with the aim of (1) characterising and optimising the ATM teleradiology platform, minimising the bandwidth requirements without degrading the quality of service offered to users and (2) evaluating the telemedicine system usability to improve the fulfillment of user's needs. The assessment outcomes have provided insights into technical limitations of broadband multimedia technologies for an optimum usage of a teleradiology co-operative diagnosis systems and the organisational difficulties and limitations involved in setting-up these new advanced telemedicine services to achieve the expected clinical benefits.

Computer Graphics↗
PubMed2000

Evaluation of DIABNET, a decision support system for therapy planning in gestational diabetes.

DIABNET is a knowledge-based system designed to aid doctors with therapy planning in gestational diabetes. The system core is a qualitative model, implemented by a Causal Probabilistic Network, that is able to detect the insulin effectiveness on a daily basis. DIABNET analyses monitoring data and proposes quantitative changes in insulin therapy and qualitative diet modifications. This paper proposes an evaluation methodology to assess the system performance when working in a real scenario. The methodology manages the absence of a gold standard and includes: a subjective analysis based on questionnaires and an objective analysis based on a quantitative comparison of the system's and experts' proposals. The paper also shows the results of two experiments in which expert diabetologists evaluated the therapeutical advice provided by DIABNET during the follow up of 9 patients with gestational diabetes. DIABNET detected the need of a therapy modification in 92% of the cases showing its appropriateness for automatic alarm generation. Around 80% of the proposals were accepted by experts. The evaluation results are encouraging and allow characterisation of the system's performance when proposing therapy modifications. Evaluation in its turn helps to refine the knowledge managed by DIABNET and enables us to look towards the further clinical use of DIABNET as a decision tool in gestational diabetes integrated in a telemedicine service.

Artificial Intelligence↗
PubMed1998

Automated FISH spot counting in interphase nuclei: statistical validation and data correction.

The evaluation of an automated system for Fluorescence In Situ Hybridization (FISH) spot counting in interphase nuclei is presented in this paper. Different types of experiments have been performed with samples from known populations. In all of them the goal is to detect mosaicism of chromosome X in leukocytes from mixtures in known proportions of healthy male and female blood. First the initial results from the automatic FISH analysis system were obtained and evaluated. Then the analysis was modified to reduce systematic errors, so that the results are closer to what an experienced human operator would have obtained (system calibration step). Finally, an additional control probe of chromosome Y was used to detect and discard cells where incorrect hybridization or other abnormal situations had occurred. In each step the system sensitivity was determined by the use of two statistical validation tests, so that the improvement brought about by the correction methods could be assessed. The results obtained in the study showed that, using both corrections, the system is able to detect 10% monosomies with a significance level alpha = 0.1%.

Algorithms↗
PubMed1998

MRI visualization of small structures using improved surface coils.

In this paper we present the spatial resolution enhancement and noise reduction level achieved with an optimized inductively coupled surface coil specifically designed for our experiments. The technique of designing and implementing customized coils for magnetic resonance imaging of very small structures is described. We have designed a low cost prototype of an inductively coupled circular surface coil, tuned for 1H magnetic resonance imaging at 200 MHz. The coil is mounted on a customized teflon support. The inductive coupling used in this coil improves the signal-to-noise ratio by reducing various loss mechanisms (specially the dielectric losses). Test images have been acquired to determine the evolution of induced articular lesions in a rabbit animal model, as well as brain tumors in rats. The images show high spatial resolution, excellent B1 field homogeneity and no "hot spots". Comparing these images with those acquired with conventional coils, one finds better spatial resolution and signal-to-noise ratio, as well as larger field of view with less intense illumination artifact. The methodology can be used in any application that requires high quality imaging of small structures.

Animals↗
PubMed1998

A broadband multimedia collaborative system for advanced teleradiology and medical imaging diagnosis.

This paper presents a new telemedicine system currently in routine clinical usage, developed within the European Union (EU) ACTS BONAPARTE project (1). The telemedicine system is developed on an asynchronous transfer mode (ATM) multimedia hardware/software platform comprising the following set of telemedicine services: synchronous cooperative work, high-quality video conference, multimedia mail, medical image digitizing, processing, storing and printing, and local and remote transparent database access. The medical information handled by the platform conforms to the Digital Imaging and Communications in Medicine (DICOM) 3.0 medical imaging standard. The telemedicine system has been installed for clinical routines in three Spanish hospitals since November 1997 and has been used in an average of one/two clinical sessions per week. At each clinical session, a usability and clinical evaluation of the system was carried out. Evaluation is carried out through direct observation of interactions and questionnaire-based subjective data. The usability evaluation methodology and the results of the system usability study are also presented in this article. The experience gained from the design, development, and evaluation of the telemedicine system is providing an indepth knowledge of the benefits and difficulties involved in the installation and clinical usage of this type of high-usability and advanced multimedia telemedicine system in the field of teleradiology and collaborative medical imaging diagnosis.

Diagnostic Imaging↗
PubMed1997

Applying watershed algorithms to the segmentation of clustered nuclei.

Cluster division is a critical issue in fluorescence microscopy-based analytical cytology when preparation protocols do not provide appropriate separation of objects. Overlooking clustered nuclei and analyzing only isolated nuclei may dramatically increase analysis time or affect the statistical validation of the results. Automatic segmentation of clustered nuclei requires the implementation of specific image segmentation tools. Most algorithms are inspired by one of the two following strategies: 1) cluster division by the detection of internuclei gradients; or 2) division by definition of domains of influence (geometrical approach). Both strategies lead to completely different implementations, and usually algorithms based on a single view strategy fail to correctly segment most clustered nuclei, or perform well just for a specific type of sample. An algorithm based on morphological watersheds has been implemented and tested on the segmentation of microscopic nuclei clusters. This algorithm provides a tool that can be used for the implementation of both gradient- and domain-based algorithms, and, more importantly, for the implementation of mixed (gradient- and shape-based) algorithms. Using this algorithm, almost 90% of the test clusters were correctly segmented in peripheral blood and bone marrow preparations. The algorithm was valid for both types of samples, using the appropriate markers and transformations.

Algorithms↗
PubMed1997

Simulated surgery on computed tomography and magnetic resonance images: an aid for intraoperative radiotherapy.

Intraoperative radiotherapy (IORT) is a relatively new technique in which irradiation with electrons is performed during an open surgery procedure. This approach poses significant problems in obtaining accurate dosimetry, since neither the pre- nor the postoperative patient images actually matches the irradiation field. Our objective was to implement a software tool able to provide an estimate of the dose distribution, overcoming the problem of the geometrical mismatch between the images and the surgical field during the irradiation. The program was developed in the C programming language, on a noncommercial version of a Philips EasyVision workstation. The application allows to create a new data set by manipulating the preoperative computed tomography and magnetic resonance images in order to simulate the final geometry of the surgical area during the IORT procedure. The exact dose distribution can then be calculated by transferring these new images to a standard radiotherapy planning system. Also an approximate dose distribution can be quickly displayed by superimposing isodose curves obtained from a water phantom. The proposed approach introduces a helpful tool for dosimetry and planning in IORT protocols, improving their accuracy and safety and allowing for more objective quality control and patient follow-up.

Brain Neoplasms↗
PubMed1997

Evaluation of autofocus functions in molecular cytogenetic analysis.

This work describes a systematic evaluation of several autofocus functions used for analytical fluorescent image cytometry studies of counterstained nuclei. Focusing is the first step in the automatic fluorescence in situ hybridization analysis of cells. Thirteen functions have been evaluated using qualitative and quantitative procedures. For the last of these procedures a figure-of-merit (FOM) is defined and proposed. This new FOM takes into account five important features of the focusing function. Our results show that functions based on correlation measures have the best performance for this type of image.

Algorithms↗
PubMed1996

A telemedicine system for remote cooperative medical imaging diagnosis.

Telemedicine is changing the classical form of health care delivery, by providing efficient solutions to an increasing number of new situations: here we consider those which require some type of computer-supported cooperative work (CSCW) between health care professionals located in different clinical sites. This paper presents the design and development of a telemedicine system for remote computer-supported cooperative medical imaging diagnosis. The main and novel component of our system is a new CSCW distributed architecture, comprised by a collaborative toolkit to add audioconferencing, telepointing, window sharing, user's coordination and application synchronization facilities, either to existing or new medical imaging diagnosis applications. In comparison with existing CSCW products, mainly based on centralized architectures, our distributed toolkit is specially designed for telemedicine applications: to allow different levels of sharing between participants, to improve user feedback in highly interactive user interfaces, and to optimize the required communication bandwidth in order to implement a telemedicine CSCW application on almost any telecommunication network. This telemedicine CSCW system has been applied to build a cooperative medical imaging diagnosis application, in which two doctors, located in different hospitals, need to achieve a cooperative diagnosis on haemodynamic studies using cardiac angiography images. The design of the graphical user interface for this kind of telemedicine CSCW systems, a critical component which conforms any telemedicine application, is also addressed with a new methodological approach, to assure the system usability and final user acceptance. The telemedicine cardiac angiography pilot has been implemented, tested and evaluated within the Research Project 'FEST-Framework for European Services in Telemedicine' funded by EU AIM Programme.

Attitude to Computers↗
PubMed1995

A home telecare management system.

The increasing tendency to discharge chronic patients from hospital, as well as the growing expectation of improved quality of life for elderly and disabled people at home, was the original motivation for the development of a home telecare management system. The system allows a service centre to perform remote monitoring of biological signals and other data via the public telephone network, as well as to manage different emergency situations arising at home. The system is part of the FU-funded EPIC project (European Prototype for Integrated Care). It was tested in Belfast (Northern Ireland) and is currently being installed in Torre del Mar (Spain). This paper describes the system design and preliminary evaluation. The results indicate that the system operators find it highly acceptable in terms of efficiency, effectiveness, helpfulness, control and learnability. Integration of home telecare data with community-care information systems is essential if data captured at home are to be incorporated into the care process effectively.

Aged↗
PubMed1994

Telehygiene system for preventive chronopharmacology in space.

A remote computerized health care (telehygiene) system for space travel includes monitoring devices and pharmaceuticals aimed at the optimization of health and the environment. Early risk indicators are provided by dynamic characteristics of rhythms of several frequencies describing variation inside the physiologic range. These rhythm characteristics, assessed as one goes, can be updated and compacted as data accumulate by the use of chronobiologic software that resolves anticipated components of lower and lower frequency, thus providing summaries of data at intervals of differing length. At any time, harbingers of risk, including characteristics of circannual rhythms, can be retrieved in an instant. On their basis, early preventive action can be instituted for risk lowering and for delivery of timed treatment when needed. Preventive or curative health care in space and terrestrial spin-offs are the more effective the more of the chronome (time-structure) is resolved.

Aerospace Medicine↗
PubMed1994

A telemedicine distributed system for cooperative medical diagnosis.

Telemedicine is changing the classical form of health care delivery, dramatically increasing the number of new applications in which some type of distributed synchronous cooperation between health care professionals is required. This paper presents the design and development of a telemedicine distributed system for cooperative medical diagnosis based on two new approaches: 1) a distributed layered architecture specially designed to add synchronous computer supported cooperative work features either to new or existing medical applications; 2) the definition of a methodological procedure to design graphical user interfaces for telemedicine cooperative working scenarios. The cooperative work is supported by a collaborative toolkit that provides telepointing, window sharing, coordination and synchronization. Finally, we have implemented and installed the telemedicine system in clinical practice between two hospitals, providing teleconferencing facilities for cooperative decision support in haemodynamics studies. This specific implementation and a preliminary evaluation were accomplished under the Research Project FEST "Framework for European Services in Telemedicine" funded by the EU AIM Programme.

Computer Communication Networks↗
PubMed1994

A hybrid knowledge based system for therapy adjustment in gestational diabetes.

This poster describes a system to analyze self-monitoring data of gestational diabetic patients, for obtaining an assessment of their metabolic control with the final goal of supporting decision-making in therapy adjustment. The system is able to manage incomplete data and to make temporal reasoning under uncertainty, the two most important constraints when analyzing ambulatory monitoring data. Two different formalism have been used to represent and manage the knowledge: a dynamic Bayesian network and a production system based on rules. The outcomes provided by the whole system are: information on possible patient transgressions of the prescribed treatment and recommendations of treatment adjustments.

Artificial Intelligence↗