Valoración de la cuantificación fiable de la dinámica del líquido cefalorraquídeo en el acueducto de Silvio mediante resonancia magnética en la hidrocefalia normopresiva idiopática / Assessment of reliable quantification of the dynamics of cerebrospinal fluid by magnetic resonance imaging in idiopathic normal pressure hydrocephalus

Introducción. Para identificar a pacientes con hidrocefalia normopresiva (HNP) idiopática es necesario combinar una buena selección clínica con la cuantificación fiable de diversos parámetros que caracterizan la dinámica del líquido cefalorraquídeo (LCR) en las imágenes por resonancia magnética (RM) obtenidas en contraste de fase. Material y métodos. Se realizó un análisis cuantitativo a 38 sujetos (19 pacientes con sospecha de HNP idiopática y 19 controles). Las imágenes se adquirieron usando un equipo de RM de 1,5 T con una secuencia contraste de fase perpendicular al acueducto de Silvio, codificada a 20 cm/s y con 27 lecturas por ciclo cardíaco mediante sincronización retrospectiva. Se definió el área del acueducto a mitad de la altura del pico de velocidad para maximizar la precisión. Los parámetros cuantificados fueron el flujo promedio, flujo máximo sistólico y diastólico, velocidad máxima sistólica y diastólica, velocidad promedio, producción de LCR y volumen por ciclo.Resultados. Todos los parámetros medidos presentaron una diferencia significativa (ANOVA: p <= 0,05) entre controles y pacientes, excepto la velocidad máxima sistólica (p=0,17). En el análisis discriminante se observó que los dos grupos (controles y pacientes) fueron clasificados correctamente en un 92,1% con el uso del flujo máximo sistólico y la producción de LCR.Conclusiones. La cuantificación semiautomática de la dinámica del LCR mediante RM diferencia a los pacientes con estado hiperdinámico de los sujetos control, con diferencias significativas que pueden usarse para clasificar las HNP idiopáticas

Introduction. A combination of good clinical selection with reliable quantification of diverse parameters that characterize the dynamics of cerebrospinal fluid (CSF) flow from phase-contrast magnetic resonance imaging may identify patients with idiopathic normal pressure hydrocephalus (NPH). Material and methods. We have carried out a quantitative analysis of 38 subjects (19 healthy subjects and 19 patients with suspected idiopathic NPH). The images were acquired using a 1.5 T MR unit with a phase-contrast sequence in an oblique-transversal plane perpendicular to the Sylvius aqueduct codified to 20 cm/s and with 27 observations per cardiac cycle by means of retrospective synchronization. The area was defined to half the height of the peak velocity, to maximize accuracy. Parameters quantified were mean flow, maximum systolic and diastolic flow, maximum systolic and diastolic velocity, mean velocity, CSF production and stroke volume. Results. All the parameters measured showed a significant difference (ANOVA: p<=0,05) between controls and patient except for the maximum systolic velocity (p=0.17). It was observed in the discriminant analysis that the two groups (controls and patients) were classified correctly in 92.1% with the use of the maximum systolic flow and CSF production. Conclusions. Semiautomatic quantification of the dynamics of CSF by means of MRI differentiates patients with hyperdynamic state from the control subjects, with significant differences that can be used to classify idiopathic HNP

Paradigma auditivo emocional en neuroimagen: una base para el estudio de la psicosis / Emotional auditory paradigm in neuroimaging: a base for the study of psychosis

Introducción. Desde la llegada de la neuroimagen numerosos estudios han tratado de analizar las diferencias en la respuesta emocional frente a la no emocional. La mayoría de estos estudios utilizan la modalidad visual (caras) y parten de los datos en sujetos normales. En el presente estudio se presenta un nuevo paradigma para el estudio de la respuesta emocional basado en la modalidad auditiva y diseñado específicamente para el estudio de la psicosis. Método. Se analizaron las palabras más frecuentes que oían los pacientes psicóticos con alucinaciones auditivas, se clasificaron según cinco categorías y a partir de las mismas se diseñó un tren de 13 palabras emocionales, comparándose con 13 palabras con la misma complejidad sintáctica y con una valencia emocional neutral. Se aplicó este paradigma para ver la activación cerebral mediante resonancia magnética funcional (RMf) en 10 varones sanos y diestros. Resultados. En los análisis preliminares se observa una clara diferenciación según el estímulo sea emocional o no emocional, tanto en la intensidad de la activación (corteza temporal derecha e izquierda) como en la activación de áreas específicas (precentral y supramarginal derecha). Conclusiones. El paradigma presentado permite observar una diferenciación en la activación cerebral de la respuesta a estímulos auditivos emocionales y podría ser de utilidad en pacientes psicóticos

Introduction. Since the arrival of neuroimaging numerous studies have tried to analyze the differences between emotional and non-emotional response. The majority of these studies use visual approach (faces) and begin with data in normal subjects. The present study introduces a new paradigm for the study of emotional response based on auditory approach and designed specifically for the study of psychoses. Method. The most frequent words heard by psychotic patients with auditory hallucinations were analyzed. They were classified according to five categories which were compared with 13 other words with the same structure but with a neutral emotional valency. This paradigm was applied to see the cerebral activation with functional magnetic resonance imaging (fMRI) in 10 right handed healthy males. Results. In the preliminary analysis a clear differentiation is observed depending on the type of stimulus applied (emotional or non-emotional), both in the intensity of activation (right and left temporal cortex) as in the activation of specific areas (right precentral and supramarginal gyrus) only with the emotional stimulus. Conclusions. The present paradigm allows the observation of a differentiation in the cerebral activation to emotional auditory stimulus and could be of utility in the study of psychotic patients

Emotional auditory paradigm in neuroimaging: a base for the study of psychosis.

INTRODUCTION: Since the arrival of neuroimaging numerous studies have tried to analyze the differences between emotional and non-emotional response. The majority of these studies use visual approach (faces) and begin with data in normal subjects. The present study introduces a new paradigm for the study of emotional response based on auditory approach and designed specifically for the study of psychoses. METHOD: The most frequent words heard by psychotic patients with auditory hallucinations were analyzed. They were classified according to five categories which were compared with 13 other words with the same structure but with a neutral emotional valency. This paradigm was applied to see the cerebral activation with functional magnetic resonance imaging (fMRI) in 10 right handed healthy males. RESULTS: In the preliminary analysis a clear differentiation is observed depending on the type of stimulus applied (emotional or non-emotional), both in the intensity of activation (right and left temporal cortex) as in the activation of specific areas (right precentral and supramarginal gyrus) only with the emotional stimulus. CONCLUSIONS: The present paradigm allows the observation of a differentiation in the cerebral activation to emotional auditory stimulus and could be of utility in the study of psychotic patients.

Estimation of atrial fibrillatory wave from single-lead atrial fibrillation electrocardiograms using principal component analysis concepts.

A new method for the assessment of the atrial fibrillatory wave (AFW) from the ECG is presented. This methodology is suitable for signals registered from Holter systems, where the reduced number of leads is insufficient to exploit the spatial information of the ECG. The temporal dependence of the bio-electrical activity were exploited using principal component analysis. The main features of ventricular and atrial activity were extracted, and several basis signals for each subspace were determined. Hence, the estimated (AFW) are reconstructed exclusively from the basis signals that formed the atrial subspace. Its main advantage with respect to adaptive template subtraction techniques was its robustness to variations in the QRST morphology, which thus minimised QRST residua. The proposed approach was first validated using a database of simulated recordings with known atrial activity content. The estimated AFW was compared with the original AFW, obtaining correlation indices of 0.774 +/- 0.106. The suitability of this methodology for real recordings was also proven, though its application to a set of paroxysmal AF ECGs. In all cases, it was possible to detect the main frequency peak, which was between 4.6 Hz and 6.9 Hz for the patients under study.