Practical aspects of functional mri in clinical examinations / Aspectos práticos de rm funcional em exames clínicos / Aspectos prácticos de la rm funcional en los exámenes clínicos

The eloquent cerebral cortices are involved in movement, sensation, speech, vision, and higher cortical functions. Functional magnetic resonance imaging (fMRI) allows the evaluation of brain function, aiding in neurosurgical planning by mapping eloquent cortical areas. Considering the high cost of the hardware involved, the purpose of this work is to present a more affordable, in-house alternative for these studies that can provide adequate results in a clinical setting. We also present some practical information on how to perform these exams. We describe an affordable in-house hardware solution used by an imaging center, and examples of fMRI paradigms used to evaluate motor and language tasks. The fMRI studies show robust activations in eloquent areas consistent with the tasks performed on the exam. Images of post-processed studies illustrate clinical cases. The fMRI have well-established applications, mapping eloquent cortical areas in patients with brain lesions. In the case of surgical planning, it allows the surgeon to maximize the resection area while minimizing sequelae. More affordable hardware can reduce the cost of these exams, making them more accessible to the general public.

O córtex cerebral eloquente está envolvido nas atividades motora, sensação, fala, visão e funções corticais superiores. A ressonância magnética funcional (RMf) permite a avaliação da função cerebral, ajudando no planejamento neurocirúrgico através do mapeamento de áreas corticais eloquentes. Considerando o elevado custo do hardware envolvido, o objetivo deste trabalho é apresentar uma alternativa mais acessível para estes estudos, que possa fornecer resultados adequados em um ambiente clínico. Também apresentamos algumas informações práticas sobre a realização destes exames. Descrevemos uma solução de hardware acessível utilizada por um centro de imagens, e exemplos de paradigmas de RMf usados para avaliar tarefas motoras e relacionadas à fala. Os estudos de RMf mostram ativações em áreas eloquentes, consistentes com as tarefas realizadas no exame com imagens de estudos pós-processados ilustrando casos clínicos. A RMf tem aplicações bem estabelecidas, mapeando áreas corticais eloquentes em pacientes com lesões cerebrais. No caso do planejamento cirúrgico, permite que o cirurgião maximize a área de ressecção enquanto minimiza potenciais sequelas. Equipamentos mais acessíveis podem reduzir o custo destes exames, podendo aumentar a disponibilização ao público em geral.

La corteza cerebral elocuente está implicada en las actividades motoras, la sensibilidad, el habla, la visión y las funciones corticales superiores. La resonancia magnética funcional (RMf) permite la evaluación de la función cerebral, ayudando en la planificación neuroquirúrgica mediante el mapeo de las áreas corticales elocuentes. Teniendo en cuenta el elevado coste del hardware implicado, el objetivo de este artículo es presentar una alternativa más asequible para estos estudios que pueda proporcionar resultados adecuados en un entorno clínico. También presentamos información práctica sobre cómo realizar estos exámenes. Describimos una solución de hardware asequible utilizada por un centro de diagnóstico por imagen, y ejemplos de paradigmas de RMf utilizados para evaluar tareas motoras y relacionadas con el habla. Los estudios de RMf muestran activaciones en áreas elocuentes, coherentes con las tareas realizadas en el examen, con imágenes de estudios postprocesados que ilustran casos clínicos. La RMf tiene aplicaciones bien establecidas en el mapeo de áreas corticales elocuentes en pacientes con lesiones cerebrales. En el caso de la planificación quirúrgica, permite al cirujano maximizar el área de resección minimizando las posibles secuelas. Un equipo más asequible puede reducir el coste de estas exploraciones, aumentando potencialmente su disponibilidad para el público en general.

Reward- and threat-related neural function associated with risk and presence of depression in adolescents: a study using a composite risk score in Brazil.

BACKGROUND: Neuroimaging studies on adolescents at risk for depression have relied on a single risk factor and focused on adolescents in high-income countries. Using a composite risk score, this study aims to examine neural activity and connectivity associated with risk and presence of depression in adolescents in Brazil. METHODS: Depression risk was defined with the Identifying Depression Early in Adolescence Risk Score (IDEA-RS), calculated using a prognostic model that included 11 socio-demographic risk factors. Adolescents recruited from schools in Porto Alegre were classified into a low-risk (i.e., low IDEA-RS and no lifetime depression), high-risk (i.e., high IDEA-RS and no lifetime depression), or clinically depressed group (i.e., high IDEA-RS and depression diagnosis). One hundred fifty adolescents underwent a functional MRI scan while completing a reward-related gambling and a threat-related face-matching task. We compared group differences in activity and connectivity of the ventral striatum (VS) and amygdala during the gambling and face-matching tasks, respectively, and group differences in whole-brain neural activity. RESULTS: Although there was no group difference in reward-related VS or threat-related amygdala activity, the depressed group showed elevated VS activity to punishment relative to high-risk adolescents. The whole-brain analysis found reduced reward-related activity in the lateral prefrontal cortex of patients and high-risk adolescents compared with low-risk adolescents. Compared with low-risk adolescents, high-risk and depressed adolescents showed reduced threat-related left amygdala connectivity with thalamus, superior temporal gyrus, inferior parietal gyrus, precentral gyrus, and supplementary motor area. CONCLUSIONS: We identified neural correlates associated with risk and presence of depression in a well-characterized sample of adolescents. These findings enhance knowledge of the neurobiological underpinnings of risk and presence of depression in Brazil. Future longitudinal studies are needed to examine whether the observed neural patterns of high-risk adolescents predict the development of depression.

Activación cerebral en estado de reposo en Default Mode Network de pacientes eutímicos con trastorno bipolar tipo I / Brain activitivation of euthymic patients with Type I bipolar disorder in resting state Default Mode Network

Introducción: Aún existen dudas sobre la conectividad cerebral en el trastorno bipolar tipo I (TBI) y son necesarios estudios con resonancia magnética funcional en estado de reposo (RMf-ER) durante la eutimia para identificar alteraciones funcionales del trastorno. Objetivo: Evaluar con RMf-ER la diferencias de activación cerebral entre los pacientes eutí-micos con TBI y los sujetos de control y explorar el efecto del litio en esta activación. Métodos: Estudio transversal de 21 pacientes eutímicos con TBI y 12 controles, usando RMf-ER y un análisis de componentes independientes. En el grupo con TBI, también se realizó una comparación entre 10 pacientes con TBI en monoterapia con litio y 11 sin medicación. Resultados: Se encontró mayor activación en el hipocampo derecho (p = 0,049) y el cíngulo posterior (p = 0,040) en la Default Mode Network (DMN) del grupo TBI frente a los controles. No hubo diferencias estadísticamente significativas entre el grupo de TBI con litio y los pacientes con TBI sin medicación. Conclusiones: Los resultados indican alteraciones en la activación y la conectividad cerebral en el TBI durante la eutimia y principalmente en el cíngulo posteriory el hipocampo dentro de la DMN, la cual podría tener relevancia en la regulación afectiva.

Introduction: As there are still doubts about brain connectivity in type I bipolar disorder (BID), resting-state functional magnetic resonance imaging (RS-fMRI) studies are necessary during euthymia for a better control of confounding factors. Objective: To evaluate the differences in brain activation between euthymic BID patients and control subjects using resting state- functional-magnetic resonance imaging (RS-fMRI), and to identify the lithium effect in these activations. Methods: A cross-sectional study was conducted on 21 BID patients (10 receiving lithium only, and 11 non-medicated) and 12 healthy control subjects, using RS fMRI and independent component analysis (ICA). Results: Increased activation was found in the right hippocampus (P = .049) and posterior cingulate (P = .040) within the Default Mode Network (DMN) when BID and control group were compared. No statistically significant differences were identified between BID on lithium only therapy and non-medicated BID patients. Conclusions: The results suggest that there are changes in brain activation and connectivity in BID even during euthymic phase and mainly within the DMN network, which could be relevant in affect regulation.

[Brain activitivation of euthymic patients with Type I bipolar disorder in resting state Default Mode Network]. / Activación cerebral en estado de reposo en Default Mode Network de pacientes eutímicos con trastorno bipolar tipo I.

INTRODUCTION: As there are still doubts about brain connectivity in type I bipolar disorder (BID), resting-state functional magnetic resonance imaging (RS-fMRI) studies are necessary during euthymia for a better control of confounding factors. OBJECTIVE: To evaluate the differences in brain activation between euthymic BID patients and control subjects using resting state- functional-magnetic resonance imaging (RS-fMRI), and to identify the lithium effect in these activations. METHODS: A cross-sectional study was conducted on 21 BID patients (10 receiving lithium only, and 11 non-medicated) and 12 healthy control subjects, using RS fMRI and independent component analysis (ICA). RESULTS: Increased activation was found in the right hippocampus (P=.049) and posterior cingulate (P=.040) within the Default Mode Network (DMN) when BID and control group were compared. No statistically significant differences were identified between BID on lithium only therapy and non-medicated BID patients. CONCLUSIONS: The results suggest that there are changes in brain activation and connectivity in BID even during euthymic phase and mainly within the DMN network, which could be relevant in affect regulation.