Usefulness of magnetic resonance spectroscopy in mesial temporal sclerosis: a systematic review.

BACKGROUND: Magnetic resonance spectroscopy (MRS) provides non-invasive information about metabolic features in different regions of the brain affected by mesial temporal sclerosis (MTS). PURPOSE: To review articles analyzing the most common alterations in biochemical parameters in MTS and the applications of MRS in presurgical assessment. METHODS: We undertook a systematic literature search for MRS in MTS in PubMed, SCOPUS, and Cochrane based on the MESH terms ""Magnetic Resonance Spectroscopy", "Proton Magnetic Resonance Spectroscopy", "Carbon-13 Magnetic Resonance Spectroscopy", "1H-MRS", "31P-MRS", "mesial temporal sclerosis", "hippocampal sclerosis", "mesial temporal seizure", and "mesial temporal epilepsy". RESULTS: Of the initial 134 articles found, 30 were selected after the exclusion process. Of these, 13 detected a decrease in N-acetylaspartate (NAA), 9 showed a decreased in the ratio NAA/Cho+Cr, and 8 demonstrated a decreased in the ratio NAA/Cr, all of them in the ipsilateral hippocampus. Nine studies also found reduced NAA levels in extrahippocampal regions. CONCLUSIONS: The main findings were a decrease in NAA in the ipsilateral hippocampus. In addition, NAA levels were low outside the hippocampus so MTS could be a more extensive disease. Patients without MTS also presented a decrease in NAA in the ipsilateral hippocampus although NAA was even lower in the MTS patients. Thus, MRS could be useful in the presurgical evaluation to locate the epileptogenic focus, but not specific for the diagnosis of MTS.

Evaluación prequirúrgica mediante resonancia magnética funcional en pacientes con tumores neuroepiteliales disembrioplásicos: una serie de casos / Preoperative evaluation by functional magnetic resonance imaging in patients with dysembryoplastic neuroepithelial tumours: A case series

INTRODUCCIÓN: Los tumores neuroepiteliales disembrioplásicos (DNET) son un tipo de neoplasia glioneuronal benigna de localización típicamente temporal que producen crisis epilépticas resistentes al tratamiento farmacológico en niños y adultos jóvenes. OBJETIVO: Se muestran 4 casos valorando la utilidad de la resonancia magnética funcional en el estudio prequirúrgico de pacientes con tumores neuroepiteliales disembrionarios. Para la obtención de imágenes se utilizó un equipo de resonancia magnética Philipps Intera de 3.0 Tesla y la técnica Blood Oxygenation Level-Dependent, permitiendo localizar las áreas elocuentes de lenguaje y motora mediante la aplicación de paradigmas específicos. RESULTADOS: En un caso el tumor se encontraba adyacente al área de Broca, en 2 casos coincidía con Wernicke, en un paciente estaba menos de 1cm del área motora de la mano y en otro próximo a la memoria. Solo 2 de los pacientes fueron operados, no produciéndose déficit funcional postoperatorio. Se observó activación hemisférica contralateral al tumor sugestivo de neuroplasticidad en uno de los pacientes. CONCLUSIONES: La resonancia magnética funcional supone un método no invasivo que permite evaluar la proximidad de las lesiones a las áreas elocuentes, clave en la evaluación del riesgo quirúrgico. Además, ha permitido detectar probable neuroplasticidad en un caso, la cual ha garantizado el éxito de la cirugía

INTRODUCTION: Dysembryoplastic neuroepithelial tumours (DNET) are a type of benign glioneuronal neoplasia of typically temporal location that produce drug-resistant epileptic seizures in children and young adults. OBJECTIVE: This work aims to assess the usefulness of functional magnetic resonance imaging (fMRI) in the preoperative study in four patients with DNET. A Philips Intera 3.0 Tesla magnetic resonance imaging scanner and the Blood-Oxygen-Level-Dependent (BOLD) technique were used to obtain the images, making it possible to locate the eloquent areas for language and motor areas through the application of specific paradigms. RESULTS: In one case the tumour was adjacent to Broca's area, in two cases it coincided with Wernicke's area, in one patient it was < 1cm from the motor area for the hand and in another close to memory. Only two of the patients were operated on, without postoperative functional deficit. Hemispheric activation contralateral to the tumour suggestive of neuroplasticity was observed in one of the patients. CONCLUSIONS: fMRI is a non-invasive method that allows us to assess the proximity of lesions to eloquent areas, which is key in the evaluation of surgical risk. In addition, it allowed the detection of probable neuroplasticity in one case, which guaranteed the success of the surgery

Preoperative evaluation by functional magnetic resonance imaging in patients with dysembryoplastic neuroepithelial tumours: A case series. / Evaluación prequirúrgica mediante resonancia magnética funcional en pacientes con tumores neuroepiteliales disembrioplásicos: una serie de casos.

INTRODUCTION: Dysembryoplastic neuroepithelial tumours (DNET) are a type of benign glioneuronal neoplasia of typically temporal location that produce drug-resistant epileptic seizures in children and young adults. OBJECTIVE: This work aims to assess the usefulness of functional magnetic resonance imaging (fMRI) in the preoperative study in four patients with DNET. A Philips Intera 3.0 Tesla magnetic resonance imaging scanner and the Blood-Oxygen-Level-Dependent (BOLD) technique were used to obtain the images, making it possible to locate the eloquent areas for language and motor areas through the application of specific paradigms. RESULTS: In one case the tumour was adjacent to Broca's area, in two cases it coincided with Wernicke's area, in one patient it was<1cm from the motor area for the hand and in another close to memory. Only two of the patients were operated on, without postoperative functional deficit. Hemispheric activation contralateral to the tumour suggestive of neuroplasticity was observed in one of the patients. CONCLUSIONS: fMRI is a non-invasive method that allows us to assess the proximity of lesions to eloquent areas, which is key in the evaluation of surgical risk. In addition, it allowed the detection of probable neuroplasticity in one case, which guaranteed the success of the surgery.