Challenges in radiological evaluation of brain metastases, beyond progression.

MRI is the cornerstone in the evaluation of brain metastases. The clinical challenges lie in discriminating metastases from mimickers such as infections or primary tumors and in evaluating the response to treatment. The latter sometimes leads to growth, which must be framed as pseudo-progression or radionecrosis, both inflammatory phenomena attributable to treatment, or be considered as recurrence. To meet these needs, imaging techniques are the subject of constant research. However, an exponential growth after radiotherapy must be interpreted with caution, even in the presence of results suspicious of tumor progression by advanced techniques, because it may be due to inflammatory changes. The aim of this paper is to familiarize the reader with inflammatory phenomena of brain metastases treated with radiotherapy and to describe two related radiological signs: "the inflammatory cloud" and "incomplete ring enhancement", in order to adopt a conservative management with close follow-up.

Los retos en la evaluación radiológica de las metástasis cerebrales, más allá de la progresión / Challenges in radiological evaluation of brain metastases, beyond progression

La resonancia magnética es la piedra angular en la evaluación de las metástasis cerebrales. Los retos clínicos residen en discriminar las metástasis de imitadores como infecciones o tumores primarios y en evaluar la respuesta al tratamiento. Este, en ocasiones, condiciona un crecimiento, que debe encuadrarse como una pseudoprogresión o una radionecrosis, ambos fenómenos inflamatorios atribuibles al mismo, o bien considerarse como una recurrencia. Para responder a estas necesidades, las técnicas de imagen son objeto de constantes investigaciones. No obstante, un crecimiento exponencial tras la radioterapia debe interpretarse con cautela, incluso ante resultados sospechosos de progresión por técnicas avanzadas, ya que puede tratarse de una radionecrosis. El objetivo de este trabajo es familiarizar al lector con los fenómenos inflamatorios de las metástasis cerebrales tratadas con radioterapia y describir dos signos radiológicos relacionados: la «nube inflamatoria» y el «realce en anillo incompleto», con el fin de adoptar un manejo conservador en estos casos.(AU)

MRI is the cornerstone in the evaluation of brain metastases. The clinical challenges lie in discriminating metastases from mimickers such as infections or primary tumors and in evaluating the response to treatment. The latter sometimes leads to growth, which must be framed as pseudo-progression or radionecrosis, both inflammatory phenomena attributable to treatment, or be considered as recurrence. To meet these needs, imaging techniques are the subject of constant research. However, an exponential growth after radiotherapy must be interpreted with caution, even in the presence of results suspicious of tumor progression by advanced techniques, because it may be due to inflammatory changes. The aim of this paper is to familiarize the reader with inflammatory phenomena of brain metastases treated with radiotherapy and to describe two related radiological signs: «the inflammatory cloud» and «incomplete ring enhancement», in order to adopt a conservative management with close follow-up.(AU)

Atlas interactivo de neuroimágenes y correlación clínico-imagenológica en ataque cerebrovascular agudo: recurso digital educativo / Interactive atlas of neuroimages and clinical correlation of images in acute cerebrovascular accident: educational digital resources

Introducción: Los recursos digitales educativos son cada día más utilizados por las instituciones educativas y los estudiantes. Presentamos todo el proceso de trabajo para hacer un objeto virtual de aprendizaje (OVA). Objetivo: Realizar e implementar un atlas interactivo de neuroimágenes con correlación clínica en enfermedad cerebrovascular isquémica aguda. Metodología: Se realizó en 3 fases: la primera consistió en el análisis y diseño del syllabus y del instruccional; en la segunda se llevó a cabo la búsqueda bibliográfica y la revisión de casos clínicos, y la última correspondió a la socialización del OVA en la plataforma institucional. Las imágenes provienen del servicio de resonancia del Hospital de San José, con resonador marca Siemens Aera y software MicroDicom en resolución PNG. Resultados: Publicación del OVA en el repositorio institucional de OVAS para el aprovechamiento de estudiantes de medicina, médicos generales, residentes de primer año de neurología y demás especialidades de la Fundación Universitaria Ciencias de la Salud. Conclusiones: Los OVA son una herramienta útil en la formación del estudiante. Se debe fomentar la investigación en este ámbito para que las nuevas generaciones incursionen más en este campo del aprendizaje...(AU)

Introduction: Digital educational resources are increasingly being used by educational institutions and students. The complete process is presented for producing a virtual learning object (OVA). Objective: To prepare and implement an interactive atlas of neuroimaging with clinical correlation in acute ischaemic cerebrovascular disease. Methodology: The project was carried out in three phases, the first of which was the analysis and instructional design of the syllabus. The second and third phase included a literature search and review of clinical cases, followed by the entering of the OVA in the institutional platform. The images come from the San Jose Hospital Magnetic Resonance Unit, using a Siemens Aera resonator with MicroDicom software in PNG resolution. Results: The OVA was published in the institutional repository of OVAS for use by medical students, general practitioners, and first year residents of neurology and other specialties of the University Health Sciences Foundation. Conclusions: OVA is a useful tool in student training. Research in this area should be encouraged so that new generations can make more inroads into this field of learning...(AU)

[Utility of diffusion-weighted magnetic resonance imaging in severe focal traumatic brain injuries]. / Utilidad de la resonancia magnética potenciada en difusión en pacientes con lesiones focales por traumatismo craneoencefálico grave.

OBJECTIVE: To describe the apparent diffusion coefficient (ADC) in a series of severe traumatic brain injuries, their clinical and outcome features, and possible implications. DESIGN: A descriptive, observational case-series study was carried out. PATIENTS AND INTERVENTIONS: Patients with severe traumatic brain injuries (TBIs) admitted to the ICU were subjected to MRI study using a 1.5 T scanner. Diffusion-weighted images (DWMR) were obtained using the following echo-planar pulse sequence: TR 10000 ms, TE 126.9 ms, with b values 1000 s/mm2 in the three spatial dimensions. Combining the three sets of images, an isotropic image conforming a map of the mean ADCs was obtained. RESULTS: DWMR was performed in 23 patients with severe TBI admitted to the ICU between 2001 and 2004. In the MR images we selected 26 regions of interest (ROIs) where ADC was recorded. We observed a clear increase in diffusion in non-treated space-occupying lesions versus other types of injuries and the normal values. A poorer outcome was recorded in patients with lower ADC values. CONCLUSIONS: Mean ADC in the lesions was greater than the normal values and greater in contusions than in other types of injuries, as an expression of extracellular edema. ADCs were decreased in patients with a poor outcome, suggesting an association between ischemia and the patient prognosis.

Helical structure of the cardiac ventricular anatomy assessed by diffusion tensor magnetic resonance imaging with multiresolution tractography.

INTRODUCTION AND OBJECTIVES: Deeper understanding of the myocardial structure linking the morphology and function of the heart would unravel crucial knowledge for medical and surgical clinical procedures and studies. Several conceptual models of myocardial fiber organization have been proposed but the lack of an automatic and objective methodology prevented an agreement. We sought to deepen this knowledge through advanced computer graphical representations of the myocardial fiber architecture by diffusion tensor magnetic resonance imaging. METHODS: We performed automatic tractography reconstruction of unsegmented diffusion tensor magnetic resonance imaging datasets of canine heart from the public database of the Johns Hopkins University. Full-scale tractographies have been built with 200 seeds and are composed by streamlines computed on the vector field of primary eigenvectors at the diffusion tensor volumes. We also introduced a novel multiscale visualization technique in order to obtain a simplified tractography. This methodology retains the main geometric features of the fiber tracts, making it easier to decipher the main properties of the architectural organization of the heart. RESULTS: Output analysis of our tractographic representations showed exact correlation with low-level details of myocardial architecture, but also with the more abstract conceptualization of a continuous helical ventricular myocardial fiber array. CONCLUSIONS: Objective analysis of myocardial architecture by an automated method, including the entire myocardium and using several 3-dimensional levels of complexity, reveals a continuous helical myocardial fiber arrangement of both right and left ventricles, supporting the anatomical model of the helical ventricular myocardial band described by F. Torrent-Guasp.