Osteoplastic Anterior Transoral Approach for Tumors of the Middle Cranial Fossa.

Surgical access to tumors involving the midline skull base remains a considerable challenge for surgeons. Various surgical approaches for treating these tumors like transnasal, transantral, and endoscopic approaches sometimes have anatomical limitations. This paper describes a transoral approach with a Lefort I osteotomy that allows a great visualization, not only to the center of the skull base but also the infratemporal fossa. This technique may be used for the surgical resection of extracranial and intracranial benign tumors, and non-neoplastic intradural pathology, which does not require dural resection. The authors will review proper patient selection, surgical exposure, operative procedure, and complications.

An anatomical signature for literacy.

Language is a uniquely human ability that evolved at some point in the roughly 6,000,000 years since human and chimpanzee lines diverged. Even in the most linguistically impoverished environments, children naturally develop sophisticated language systems. In contrast, reading is a learnt skill that does not develop without intensive tuition and practice. Learning to read is likely to involve ontogenic structural brain changes, but these are nearly impossible to isolate in children owing to concurrent biological, environmental and social maturational changes. In Colombia, guerrillas are re-integrating into mainstream society and learning to read for the first time as adults. This presents a unique opportunity to investigate how literacy changes the brain, without the maturational complications present in children. Here we compare structural brain scans from those who learnt to read as adults (late-literates) with those from a carefully matched set of illiterates. Late-literates had more white matter in the splenium of the corpus callosum and more grey matter in bilateral angular, dorsal occipital, middle temporal, left supramarginal and superior temporal gyri. The importance of these brain regions for skilled reading was investigated in early literates, who learnt to read as children. We found anatomical connections linking the left and right angular and dorsal occipital gyri through the area of the corpus callosum where white matter was higher in late-literates than in illiterates; that reading, relative to object naming, increased the interhemispheric functional connectivity between the left and right angular gyri; and that activation in the left angular gyrus exerts top-down modulation on information flow from the left dorsal occipital gyrus to the left supramarginal gyrus. These findings demonstrate how the regions identified in late-literates interact during reading, relative to object naming, in early literates.

Saliency of breast lesions in breast cancer detection using artificial intelligence.

The analysis of mammograms using artificial intelligence (AI) has shown great potential for assisting breast cancer screening. We use saliency maps to study the role of breast lesions in the decision-making process of AI systems for breast cancer detection in screening mammograms. We retrospectively collected mammograms from 191 women with screen-detected breast cancer and 191 healthy controls matched by age and mammographic system. Two radiologists manually segmented the breast lesions in the mammograms from CC and MLO views. We estimated the detection performance of four deep learning-based AI systems using the area under the ROC curve (AUC) with a 95% confidence interval (CI). We used automatic thresholding on saliency maps from the AI systems to identify the areas of interest on the mammograms. Finally, we measured the overlap between these areas of interest and the segmented breast lesions using Dice's similarity coefficient (DSC). The detection performance of the AI systems ranged from low to moderate (AUCs from 0.525 to 0.694). The overlap between the areas of interest and the breast lesions was low for all the studied methods (median DSC from 4.2% to 38.0%). The AI system with the highest cancer detection performance (AUC = 0.694, CI 0.662-0.726) showed the lowest overlap (DSC = 4.2%) with breast lesions. The areas of interest found by saliency analysis of the AI systems showed poor overlap with breast lesions. These results suggest that AI systems with the highest performance do not solely rely on localized breast lesions for their decision-making in cancer detection; rather, they incorporate information from large image regions. This work contributes to the understanding of the role of breast lesions in cancer detection using AI.

Episodic Past, Future, and counterfactual thinking in Relapsing-Remitting Multiple sclerosis.

Multiple sclerosis (MS) is a progressive disease characterized by widespread white matter lesions in the brain and spinal cord. In addition to well-characterized motor deficits, MS results in cognitive impairments in several domains, notably in episodic autobiographical memory. Recent studies have also revealed that patients with MS exhibit deficits in episodic future thinking, i.e., our capacity to imagine possible events that may occur in our personal future. Both episodic memory and episodic future thinking have been shown to share cognitive and neural mechanisms with a related kind of hypothetical simulation known as episodic counterfactual thinking: our capacity to imagine alternative ways in which past personal events could have occurred but did not. However, the extent to which episodic counterfactual thinking is affected in MS is still unknown. The current study sought to explore this issue by comparing performance in mental simulation tasks involving either past, future or counterfactual thoughts in relapsing-remitting MS. Diffusion weighted imaging (DWI) measures were also extracted to determine whether changes in structural pathways connecting the brain's default mode network (DMN) would be associated with group differences in task performance. Relative to controls, patients showed marked reductions in the number of internal details across all mental simulations, but no differences in the number of external and semantic-based details. It was also found that, relative to controls, patients with relapsing-remitting MS reported reduced composition ratings for episodic simulations depicting counterfactual events, but not so for actual past or possible future episodes. Additionally, three DWI measures of white matter integrity-fractional anisotropy, radial diffusivity and streamline counts-showed reliable differences between patients with relapsing-remitting MS and matched healthy controls. Importantly, DWI measures associated with reduced white matter integrity in three association tracts on the DMN-the right superior longitudinal fasciculus, the left hippocampal portion of the cingulum and the left inferior longitudinal fasciculus-predicted reductions in the number of internal details during episodic counterfactual simulations. Taken together, these results help to illuminate impairments in episodic simulation in relapsing-remitting MS and show, for the first time, a differential association between white matter integrity and deficits in episodic counterfactual thinking in individuals with relapsing-remitting MS.

[Changes in predictors of school performance in secondary school]. / Cambios en las variables predictoras del rendimiento escolar en Enseñanza Secundaria.

The aim of this paper is to identify the functions that best predict school achievement among adolescents and whether they change or remain stable as pupils grow older. For this purpose, we used a sample of 1392 pupils of both sexes, belonging to second and fourth grades of Secondary School of Galicia (Spain). The students were assessed with a battery of instruments that provided data about a range of variables such as family system, personal characteristics, social relationships, goal orientation, attributional variables, attitudes towards evaluation and studies, as well as learning processes and strategies. Sixty-eight potentially predictive variables were obtained and they were subsequently related to "high", "intermediate" and "low" levels of school achievement by means of discriminant analysis. Results showed that school achievement can be discriminated by two functions, which include 12 variables in second grade, dropping to 8 in fourth grade. Of these, only five are common to both years. The results of this research project support the idea that the functions that best predict school achievement vary throughout Secondary Education.

[Effect of the level of stimulus awareness on expectancy learning]. / Efecto del nivel de consciencia de la presencia del estímulo sobre el aprendizaje de expectativa.

The purpose of this experiment was to study the effects of the level of awareness of the stimuli on expectancy learning. Nine-two participants received repeated presentations of two stimulus sequences (E1A-->E2A and E1B-->E2B), E1 being a masked stimulus. E2 were imperative stimuli for a reaction time (RT) task. After the acquisition phase, all participants were tested with 10 presentations of compatible (E1A-->E2A and E1B-->E2B) and incompatible (E1A-->E2B and E1B-->E2A) stimulus sequences. According to the awareness level of the masked E1 stimuli, the participants were divided into three groups. The RT in the testing phase was faster in compatible than in incompatible stimulus sequences, but only in the unconscious group. These results are considered strong evidence of expectancy learning without awareness of the stimuli and suggest that E1 awareness interferes the manifestation of expectancy learning.

Eficacia de lutecio-177 DOTATATE/TOC en pacientes con tumores neuroendocrinos bien diferenciados en estado avanzado. Ensayo clínico fase II / Efficacy of Lutetium-177 DOTATATE/TOC in Advanced Neuroendocrine Tumors

Resumen Introducción: En 2009, el Instituto Nacional de Cancerología (INC) elaboró el 177Lu-DOTATATE/TOC. El propósito del estudio fue demostrar la eficacia de estos radiopéptidos en el tratamiento paliativo de pacientes con tumores neuroendocrinos (TNE) avanzados inoperables (metastásicos o localmente avanzados) y en progresión. Métodos: Ensayo clínico abierto fase II de un solo brazo en 13 pacientes adultos con TNE grado 1 o 2, con expresión de receptores de somatostatina en lesiones blanco demostrada por captación Krenning 3 o 4 en 99mTc-HYNIC TOC. Los pacientes fueron tratados con 177Lu-DOTATATE o 177Lu-DOTATOC (según disponibilidad) a una actividad acumulativa proyectada de 600-800 mCi dividida en 3-4 dosis cada 6-9 semanas comenzando siempre con una actividad fija de 200 mCi y dosimetría con la primera dosis. El desenlace primario fue la respuesta objetiva calculada 6 y 12 meses después de la última dosis del tratamiento. Resultados: Se incluyeron 13 pacientes (7 mujeres) de 63 ± 11,6 años con TNE avanzado inoperable y en progresión. La actividad final administrada fue de 800 mCi, 600 mCi, 400 mCi y 200 mCi en 4, 7, 1 y 1 pacientes, respectivamente. La tasa de control de enfermedad a 6 y 12 meses fue de 69,2% y 45,5%, respectivamente, logrando únicamente enfermedad estable. Fallecieron 7 pacientes, 2 de ellos en los primeros 6 meses. La mediana de supervivencia global a partir de la última dosis del radiopéptido fue de 15,7 meses. Conclusiones: Se corroboró la eficacia y la seguridad del tratamiento con los radiopéptidos en NETs avanzados.

Abstract Objectives: The National Cancer Institute first elaborated 177Lu-DOTATATE/TOC in 2009. The purpose of this study was to prove the efficacy of these radiopeptides in the palliative treatment of patients with progressive advanced inoperable neuroendocrine tumors (NETs). Methods: A single-phase phase II open clinical trial was conducted in 13 adult patients with grade 1 y 2 NETs, with expression of somatostatin receptors in target lesions proven by Krenning Score 3 or 4 uptake in 99mTc-HYNIC TOC. Patients were treated with 177Lu-DOTATATE or 177Lu-DOTATOC (depending upon availability) at a projected acumulative activitiy of 600-800 mCi divided into 3-4 doses every 6-9 weeks always beginning with a fixed activity of 200 mCi and dosimetry during the first dose. The primary outcome was objective response to therapy. Results: 13 patients (7 women) aged 63 ± 11.6 years with inoperable advanced NETs were included. The final therapeutic administered activity was 800 mCi, 600 mCi, 400 mCi and 200 mCi in 4, 7, 1 and 1 patients, respectively. The disease control rate at 6 and 12 months was 69.2% and 45.5%, respectively, only obtaining stable disease. Six patients died, 2 of them in the first 6 months. Median overall survival was 15.7 months from the last treatment dose. Conclusions: The efficacy of the treatment with 177Lu-DOTATATE or 177Lu-DOTATOC radiopeptides elaborated in-house was confirmed, becoming a management alternative for patients with advanced NETs.

Análisis de espectros de resonancia magnética / Magnetic resonance spectrum analysis

Objetivo: Estudiar el comportamiento del uso de razones entre metabolitos y de la comparación de un volumen de interés con uno contralateral para determinar cuál de estas 2 técnicas es la más apropiada para obtener una relación del comportamiento metabólico de un espectro de resonancia magnética. Métodos: Fueron reclutados 10 voluntarios sanos, en los que fueron analizados el lóbulo parietal, el lóbulo temporal y los ganglios basales. Resultados: La cuantificación directa del espectro mostró un mayor coeficiente de variación dentro de los análisis realizados, lo cual justifica usar técnicas con referentes endógenos. El estudio de un volumen contralateral mostró ser una técnica con dispersión e índice de lateralidad altos. El uso de la creatina (Cr) como metabolito de control presentó un coeficiente de variación menor que la primera técnica evaluada. Los resultados hallados (ganglios basales: n-acetil-aspartato/Cr: 3 ± 6; colina/Cr: 2 ± 4. Lóbulo temporal: N-acetil-aspartato/Cr: 5 ± 5; colina/Cr: 8 ± 12. Lóbulo parietal: N-acetil-aspartato/Cr: 2,0 ± 0,6; colina/Cr: 0,9 ± 0,5) muestran valores similares a los encontrados en la literatura, con variaciones regionales considerables. Conclusiones: La técnica de cuantificación de la razón de los metabolitos con la Cr es la más adecuada para usar en el Instituto Nacional de Cancerología, por tener una dispersión menor y por arrojar valores cercanos a los reportados en la literatura en las diferentes regiones anatómicas estudiadas.

Objective: To study the performance in the use of metabolite ratios and the comparison of a contralateral volume of interest in order to determine which of these two techniques is most suitable for obtaining a ratio of the metabolite behaviour of a magnetic resonance spectrum. Methods: The parietal lobe, the temporal lobe, and basal ganglions were analysed in the 10 healthy volunteers included in the study. Results: The direct quantification of the spectra showed a wide coefficient of variation within the analyses performed, which justified using techniques with endogenous references. The study of a contralateral volume showed to be a technique with a high dispersion and laterality index. The use of creatinine (Cr) as a control metabolite had a lower coefficient of variation than the first technique evaluated. The results obtained (basal ganglions: N-acetyl-aspartate/Cr: 3 ± 6; choline/Cr: 2 ± 4. Temporal lobe: N-acetyl-aspartate/Cr: 5 ± 5; choline/Cr: 8 ± 12. Parietal Lobe: N-acetyl-aspartate/Cr: 2.0 ± 0.6; choline/Cr: 0.9 ± 0.5) showed similar values to those obtained in the literature, with considerable anatomical region variations. Conclusions: The technique that measures the ratio of the metabolites with Cr is the most suitable for use in the Instituto Nacional de Cancerología (National Oncology Institute), due to having a lower dispersion and producing results near those repo rted in the literature in the different anatomical regions studied.

Esclerosis Lupoide / Lupoid sclerosis

La esclerosis lupoide es una entidad de exclusión que reúne características fisiopatológicas, clínicas e imagenológicas comunes entre e lupus eritematoso sistémico (LES) y esclerosis múltiple (EM). El propósito del artículo es revisar aspectos inmunológicos, de laboratorio y diagnósticos diferenciales que faciliten comprobar la EL como una entidad clínica y definir las mejores posibilidades terapéuticas.

Lupoid sclerosis is a diagnosis of exclusion with similar clinical, inmunological and imagenological findings between erithematous systemic lupus (SLE) and multiple sclerosis (MS). The aim of this article is to review immunology, laboratory differential diagnosis and treatment to facilitate the understanding of EL as a clinical entity.

Efectos biológicos y aspectos de seguridad de las radiaciones no ionizantes en la resonancia magnética / Non-Ionizing Biological Effects and Security Issues in Magnetic Resonance

Objetivo: Hacer una revisión, en español, de los efectos biológicos determinísticos de los campos magnéticos estáticos, dinámicos y de radiofrecuencia, propios de los exámenes de resonancia magnética (RM) en hospitales. Metodología: Se hace referencia a los límites definidos dependiendo de los distintos usos de la radiofrecuencia en un examen de RM y sus posibles efectos biológicos. Además, se muestran los aspectos de seguridad que deben tenerse en cuenta cuando se diseñan zonas que incluyan esta técnica diagnóstica. Finalmente, se hace una breve revisión de los temas que deben tener en cuenta los entes reguladores ante este tipo de exámenes con radiaciones no ionizantes. Conclusiones: A pesar de no ser determinantes los estudios sobre riesgo biológico, sí hay riesgos, principalmente por la existencia de altos campos magnéticos, que aconsejan tener ciertas precauciones en cuanto a instalaciones y personal calificado, así como una legislación acorde, de la que, por otra parte, carece Colombia.

Objective: To review the deterministic biological effects of static, dynamic and dependent magnetic fields used in clinical magnetic resonance imaging (MRI). Methods: The suggested limits are referenced depending on the different MRI applications, as well as their possible biological effects. In addition, safety aspects which must be taken into account when areas that include this diagnostic technique are shown. Lastly, a short description of the important items for the regulatory authorities to consider when facing these types of test with non-ionizing radiation is discussed. Conclusions: Even though there is no agreement in the literature about the biological risks, risks do exist due to the presence of high magnetic fields. Specific precautions should be taken in terms of proper facilities and qualified personnel, as well as an appropriate legislation which does not exist in Colombia.

Herniación cardiaca como complicación de ventana pericárdica / Cardiac herniation as a complication of pericardiac window

La herniación cardiaca se define como la protrusión del corazón a través de un defecto pericárdico de origen iatrogénico, traumático o congénito. en este artículo se presenta el caso de una herniación cardiaca de origen iatrogénico, posterior a la realización de una ventana pericárdica. la de tipo agudo usualmente ocurre en el período posquirúrgico inmediato, casi siempre dentro de las primeras 24 horas después de la cirugía. es una complicación fatal si no es detectada y corregida a tiempo.

Xantroastrocitoma pleomórfico: presentación de un caso

Se presenta el caso de una paciente de 3 años y 10 meses cuya sintomatología neurológica, de 3 meses de evolución, consistía en rotación externa de pie izquierdo y arrastre del pie en marcha, asociado a cambios de comportamiento. En los estudios imagenologicos con escanografía y resonancia magnética, se evidenció una gran masa en lóbulo temporal derecho heterogénea, de bordes bien delimitados. WEs llevada a cirugía y el gran reporte histológico e inmunohistoquímico GFAP (Proteína Acida Glial Fibrilar) es de Xantoastrocitoma pleomorfico, como hallazgo adicional se encontró actividad mitótica aumentada lo cual habla de mal pronostico

Hemostasia y radiología

La presente revisión pretende actualizar conceptos de utilidad para el radiólogo intervencionista en relación con la fisiología del mecanismo de la coagulación, la interpretación del laboratorio en los diferentes pasos de la hemostasia y el enfoque de las patologías hemorragicas más frecuentes

Neuroimagen de la toxoplasmosis en el paciente con Sida / Tomographic images in patient with AIDS and neurologic syptoms

Se realiza la revisión de la literatura del compromiso del SNC en el paciente con SIDA, ilustrando los casos con imágenes de pacientes atendidos en el HSJD. Se propone un árbol de decisiones en pacientes con sintomatología neurológica y diagnóstico de SIDA

Las estrategias de aprendizaje: revision teorica y conceptual / Learning strategies: theoretical and conceptual analysis

Se presenta un análisis teórico y conceptual de las estrategias de aprendizaje, uno de los temas mas importantes en los últimos años dentro de la Psicología la Educación. Las cuestiones esenciales que se abordan son las siguientes: el concepto de estrategia, los procesos y etapas implicados, los diferentes sistemas de clasificación, y la enseñanza de estrategias de aprendizaje.