Is MDCT enough reliable for the evaluation of acute colitis including the underlying etiology? : correlation with colonoscopy and pathology : P2

Purpose: 1. To assess the diagnostic value of MDCT for acute colitis of various origin confirmed by colonoscopy and histology. 2. To evaluate the accuracy of MDCT of making the correct differential diagnosis. Methods and materials: The electronic hospital database from January 2006 to August 2008 revealed 351 patients with acute colitis of any origin wdetected by colonoscopy. In 85 out of these patients MDCT had been simultaneously performed (delay 3.1 days). Two radiologists jointly reviewed their corresponding CT features without knowledge of pathology and correlated them with the final histological diagnosis. Results: Eighty patients were finally included (46 women, mean age 63.4). Colitis was of ischemic (n = 35, 44%) or infectious (n = 15, 19%) origin. 18 patients (23%) had acute ulcerative colitis or Crohn's disease, in 10 patients (12%) another inflammatory cause and in two patients (2%) post radiation colitis was proven. MDCT was positive in 63 patients (78.9%). In 11 out of the 17 negative MDCT, the examination had been performed without large bowel distention. Ischemic colitis was responsible for 47.1% of the negative MDCT. Correct differential diagnosis was made in 32 (50.7%) out of the 63 positive MDCT. Among the different etiologies, the ischemic colitis was the most often misdiagnosed cause (n = 17, 58.6%). Conclusion: Large bowel distension is mandatory for reliable MDCT detection of acute colitis of any origin. Among the different aetiologies the ischemic cause is the most often associated with false negative MDCT findings and, in case of positive features, the most difficult to recognize as such.

T1-weighted MRI as a substitute to CT for refocusing planning in MR-guided focused ultrasound.

Precise focusing is essential for transcranial MRI-guided focused ultrasound (TcMRgFUS) to minimize collateral damage to non-diseased tissues and to achieve temperatures capable of inducing coagulative necrosis at acceptable power deposition levels. CT is usually used for this refocusing but requires a separate study (CT) ahead of the TcMRgFUS procedure. The goal of this study was to determine whether MRI using an appropriate sequence would be a viable alternative to CT for planning ultrasound refocusing in TcMRgFUS. We tested three MRI pulse sequences (3D T1 weighted 3D volume interpolated breath hold examination (VIBE), proton density weighted 3D sampling perfection with applications optimized contrasts using different flip angle evolution and 3D true fast imaging with steady state precision T2-weighted imaging) on patients who have already had a CT scan performed. We made detailed measurements of the calvarial structure based on the MRI data and compared those so-called 'virtual CT' to detailed measurements of the calvarial structure based on the CT data, used as a reference standard. We then loaded both standard and virtual CT in a TcMRgFUS device and compared the calculated phase correction values, as well as the temperature elevation in a phantom. A series of Bland-Altman measurement agreement analyses showed T1 3D VIBE as the optimal MRI sequence, with respect to minimizing the measurement discrepancy between the MRI derived total skull thickness measurement and the CT derived total skull thickness measurement (mean measurement discrepancy: 0.025; 95% CL (-0.22-0.27); p = 0.825). The T1-weighted sequence was also optimal in estimating skull CT density and skull layer thickness. The mean difference between the phase shifts calculated with the standard CT and the virtual CT reconstructed from the T1 dataset was 0.08 ± 1.2 rad on patients and 0.1 ± 0.9 rad on phantom. Compared to the real CT, the MR-based correction showed a 1 °C drop on the maximum temperature elevation in the phantom (7% relative drop). Without any correction, the maximum temperature was down 6 °C (43% relative drop). We have developed an approach that allows for a reconstruction of a virtual CT dataset from MRI to perform phase correction in TcMRgFUS.

IMRT credentialing for prospective trials using institutional virtual phantoms: results of a joint European Organization for the Research and Treatment of Cancer and Radiological Physics Center project.

BACKGROUND AND PURPOSE: Intensity-modulated radiotherapy (IMRT) credentialing for a EORTC study was performed using an anthropomorphic head phantom from the Radiological Physics Center (RPC; RPCPH). Institutions were retrospectively requested to irradiate their institutional phantom (INSTPH) using the same treatment plan in the framework of a Virtual Phantom Project (VPP) for IMRT credentialing. MATERIALS AND METHODS: CT data set of the institutional phantom and measured 2D dose matrices were requested from centers and sent to a dedicated secure EORTC uploader. Data from the RPCPH and INSTPH were thereafter centrally analyzed and inter-compared by the QA team using commercially available software (RIT; ver.5.2; Colorado Springs, USA). RESULTS: Eighteen institutions participated to the VPP. The measurements of 6 (33%) institutions could not be analyzed centrally. All other centers passed both the VPP and the RPC ±7%/4 mm credentialing criteria. At the 5%/5 mm gamma criteria (90% of pixels passing), 11(92%) as compared to 12 (100%) centers pass the credentialing process with RPCPH and INSTPH (p = 0.29), respectively. The corresponding pass rate for the 3%/3 mm gamma criteria (90% of pixels passing) was 2 (17%) and 9 (75%; p = 0.01), respectively. CONCLUSIONS: IMRT dosimetry gamma evaluations in a single plane for a H&N prospective trial using the INSTPH measurements showed agreement at the gamma index criteria of ±5%/5 mm (90% of pixels passing) for a small number of VPP measurements. Using more stringent, criteria, the RPCPH and INSTPH comparison showed disagreement. More data is warranted and urgently required within the framework of prospective studies.

Dual-Energy CT: Basic Principles, Technical Approaches, and Applications in Musculoskeletal Imaging (Part 1).

In recent years, technological advances have allowed manufacturers to implement dual-energy computed tomography (DECT) on clinical scanners. With its unique ability to differentiate basis materials by their atomic number, DECT has opened new perspectives in imaging. DECT has been used successfully in musculoskeletal imaging with applications ranging from detection, characterization, and quantification of crystal and iron deposits; to simulation of noncalcium (improving the visualization of bone marrow lesions) or noniodine images. Furthermore, the data acquired with DECT can be postprocessed to generate monoenergetic images of varying kiloelectron volts, providing new methods for image contrast optimization as well as metal artifact reduction. The first part of this article reviews the basic principles and technical aspects of DECT including radiation dose considerations. The second part focuses on applications of DECT to musculoskeletal imaging including gout and other crystal-induced arthropathies, virtual noncalcium images for the study of bone marrow lesions, the study of collagenous structures, applications in computed tomography arthrography, as well as the detection of hemosiderin and metal particles.

Dual-Energy CT: Basic Principles, Technical Approaches, and Applications in Musculoskeletal Imaging (Part 2).

In recent years, technological advances have allowed manufacturers to implement dual-energy computed tomography (DECT) on clinical scanners. With its unique ability to differentiate basis materials by their atomic number, DECT has opened new perspectives in imaging. DECT has been successfully used in musculoskeletal imaging with applications ranging from detection, characterization, and quantification of crystal and iron deposits, to simulation of noncalcium (improving the visualization of bone marrow lesions) or noniodine images. Furthermore, the data acquired with DECT can be postprocessed to generate monoenergetic images of varying kiloelectron volts, providing new methods for image contrast optimization as well as metal artifact reduction. The first part of this article reviews the basic principles and technical aspects of DECT including radiation dose considerations. The second part focuses on applications of DECT to musculoskeletal imaging including gout and other crystal-induced arthropathies, virtual noncalcium images for the study of bone marrow lesions, the study of collagenous structures, applications in computed tomography arthrography, as well as the detection of hemosiderin and metal particles.

La construcció virtual de la ment : implicacions psicoeducatives. 'La construcción virtual de la mente : implicaciones psicoeducativas'.

Se analiza el nuevo uso dado a las TIC y cómo esto promueve un proceso de construcción virtual de la mente. Los agentes educativos deben ser una herramienta para la construcción virtual de la mente, un recurso de gestión de la información. La educación debe ayudar a construir una mente capaz de enfrentarse a los retos del futuro de modo estratégico.

L'educació com a creació de microcultures : de la comunitat local a la xarxa virtual. 'La educación como creación de microculturas : de la comunidad local a la red virtual'.

Resumen basado en el de los autores

Divulgamat : Centro Virtual de Divulgación de las Matemáticas.

Presentación del portal Divulgamat. Este recurso electrónico depende de la Comisión de Divulgación de la Real Sociedad Matemática Española. Se estudia la estructura del portal, los distintos ámbitos que cubre y los materiales que ofrece.

Trabajo cooperativo en el entorno de aprendizaje del campus virtual de la UOC : el caso de la asignatura multimedia y comunicación.

En la Universitat Oberta de Catalunya (UOC) se experimenta con distintas situaciones de trabajo cooperativo en el entorno virtual de aprendizaje del Campus Virtual. La asignatura Multimedia y Comunicación es idónea para aprender a utilizar los instrumentos y adquirir el máximo rendimiento de las posibilidades de la información y la comunicación para trabajar en equipo sin coincidir ni en el espacio ni en el tiempo.

El diseño de una asignatura virtual para un proyecto interuniversitario.

Intercampus es un proyecto de un conjunto de universidades catalanas con el soporte del Comissionat per a la Societat de la informació y el Comissionat per a Universitats i Recerca, que tiene como objetivo poner en marcha una experiencia piloto de intercambio de asignaturas de libre elección que se impartirán mediante Internet. Se describe la experiencia del curso Herramientas Telemáticas aplicadas a la Formación para el proyecto Intercampus desarrollado simultáneamente con alumnos de ocho universidades durante el curso 1999-2000, a partir de la valoración realizada por los participantes.

Fundación Universidad-empresa de las Islas Baleares, aula virtual : la innovación al servicio de la empresa.

La universidad de las Islas Baleares a través de la Fundación Universidad Empresa (FUEIB), ha puesto en marcha un aula virtual que sigue algunos de los principios básicos del aprendizaje abierto.El aula virtual de la FUEIB es una respuesta a las necesidades de mejora de las competencias de la plantilla de las empresas mediante un modelo de formación innovador que permita la adecuación del tiempo de trabajo y formación.

Es el debate virtual sustancialmente diferente del debate presencial? : una propuesta de implemenatción de debate virtual.

La convergencia hacia el Espacio Europeo de Educación requiere del estudiante un mayor trabajo autónomo. En este contexto las tecnologías de la información y la comunicación pueden facilitar el proceso de enseñanza-aprendizaje al permitir crear espacios para la comunicación asincrónica que permiten establecer un diálogo reflexivo entre los participantes a través del envío y de la recepción de mensajes electrónicos. En el presente artículo se discute sobre la conveniencia de la utilización de la discusión virtual como un instrumento de evaluación y de sus ventajas y limitaciones en comparación con el cara a cara debate. Se comenta asimismo el papel que el instructor debería asumir en las distintas fases del debate virtual.

El Campus Virtual de la Universitat Oberta de Catalunya : un campus en cont??nua evoluci??

El nacimiento de la Universitat Oberta de Catalu??a aporta al Sistema educativo actual una forma diferente de entender tanto el proceso de ense??anza-aprendizaje universitarios, como una nueva manera de entender la misma universidad. La Universitat Oberta de Catalu??a es un campus virtual, un campus al que se puede acceder en cualquier momento y desde cualquier lugar. Un campus siempre abierto, que ha de posibilitar una nueva manera de moverse y de estudiar en la universidad.

Proyecto Benvic-Benchmarketing en el Campus Virtual : una metodología y criterios de calidad para evaluar.

El Objetivo del proyecto europeo Benvic es crear una metodología y unos criterios de calidad que permitan evaluar diferentes modelos de entornos virtuales de aprendizaje creados para ofrecer formación no presencial. Actualmente se da la oportunidad de desarrollar un sistema de formación virtual y disponer un entorno de calidad que se sitúe a la altura de los demás. Dado el creciente interés que están teniendo los sistemas de formación no presencial en línea, tres universidades europeas y tres institutos de investigación también europeos, valoraron positivamente la participación en este proyecto.

Virtual Trip : Viatge Virtual. 'Virtual Trip : Viaje Virtual'.

Se comenta la creación de un crédito variable de ESO, donde los alumnos, además de mejorar sus conocimientos de lengua inglesa en todos los niveles (escritura, lectura, habla y comprensión oral), pueden también ampliar sus conocimientos sobre la cultura de diferentes países del mundo utilizando las nuevas tecnologías. Se utiliza una gran gama de nuevos recursos: Internet, CD-ROMs, correo electrónico, creación de Webs y un vídeo. Se trata de una actividad interdisciplinar y se puede utilizar en cualquier centro de secundaria donde los alumnos tengan acceso a la red. Resumen de la autora.