OBJETIVO: O objetivo deste estudo é descrever as características do sinal nas lesões císticas da neurocisticercose nas imagens ponderadas em difusão e os metabólitos encontrados na espectroscopia de prótons. MATERIAL E MÉTODOS: Estudaram-se 38 pacientes (39 lesões) com neurocisticercose, usando-se difusão e espectroscopia de prótons. Os exames foram realizados em um magneto de 1,5 T (Signa Horizon LX: GE Medical Systems). A difusão foi realizada no plano axial, com múltiplos cortes com seqüência eco planar. A espectroscopia de prótons utilizou a seqüência PRESS (point-resolved spectroscopy) com TR of 1500 ms e TE de 30/135 ms. RESULTADOS: Os cistos apresentaram intensidade de sinal similar a do líquido cefalorraqueano (LCR) na difusão e valores de CDA sobreponíveis, variando de 1,36 a 3,18 x 10-3 mm2/s. Os picos detectáveis na espectroscopia foram lactato (96,3%), succinato (48%), alanina (40%), lipídeos (15%), aminoácidos citosólicos (7,5%) e acetato (3,7%). CONCLUSÃO: As lesões císticas da neurocisticercose apresentaram hipossinal na difusão e os picos encontrados na espectroscopia de prótons, em ordem decrescente de freqüência, foram lactato, succinato, alanina, lipídeos, aminoácidos citosólicos e acetato / PURPOSE: The objective of this study is to describe the signal behavior of cystic neurocysticercotic lesions on diffusion-weighted imaging (DWI) and single voxel proton spectroscopy findings. MATERIALS AND METHODS: We studied 38 patients (39 lesions) with neurocysticercosis, using diffusion-weighted images and proton MR spectroscopy. The examinations were performed on a 1.5 T scanner (Signa Horizon LX: GE Medical Systems). DWI was performed in the axial plane, using a multisection single shot echo planar pulse sequence. The single voxel proton spectroscopy technique used was the point-resolved spectroscopy (PRESS) sequence with a TR of 1500 ms, short and long TE of 30/135 ms. RESULTS: The cysts presented similar signal intensity to the CSF on DWI, with comparable ADC values, ranging from 1.36 to 3.18 x 10-3 mm2/s. The detectable peaks were lactate (96.3%), succinate (48%), alanine (40%), lipids (15%), cytosolic amino acids (7.5%) and acetate (3.7%). CONCLUSION: The cysts of neurocysticercosis presented hyposignal on DWI and peaks of lactate, succinate, alanine, lipids, cytosolic amino acids and acetate in proton spectroscopy, in decreasing order of frequency

OBJETIVO: O objetivo deste estudo é descrever as características do sinal nas lesões císticas da neurocisticercose nas imagens ponderadas em difusão e os metabólitos encontrados na espectroscopia de prótons. MATERIAL E MÉTODOS: Estudaram-se 38 pacientes (39 lesões) com neurocisticercose, usando-se difusão e espectroscopia de prótons. Os exames foram realizados em um magneto de 1,5 T (Signa Horizon LX: GE Medical Systems). A difusão foi realizada no plano axial, com múltiplos cortes com seqüência eco planar. A espectroscopia de prótons utilizou a seqüência PRESS (point-resolved spectroscopy) com TR of 1500 ms e TE de 30/135 ms. RESULTADOS: Os cistos apresentaram intensidade de sinal similar a do líquido cefalorraqueano (LCR) na difusão e valores de CDA sobreponíveis, variando de 1,36 a 3,18 x 10-3 mm2/s. Os picos detectáveis na espectroscopia foram lactato (96,3%), succinato (48%), alanina (40%), lipídeos (15%), aminoácidos citosólicos (7,5%) e acetato (3,7%). CONCLUSÃO: As lesões císticas da neurocisticercose apresentaram hipossinal na difusão e os picos encontrados na espectroscopia de prótons, em ordem decrescente de freqüência, foram lactato, succinato, alanina, lipídeos, aminoácidos citosólicos e acetato / PURPOSE: The objective of this study is to describe the signal behavior of cystic neurocysticercotic lesions on diffusion-weighted imaging (DWI) and single voxel proton spectroscopy findings. MATERIALS AND METHODS: We studied 38 patients (39 lesions) with neurocysticercosis, using diffusion-weighted images and proton MR spectroscopy. The examinations were performed on a 1.5 T scanner (Signa Horizon LX: GE Medical Systems). DWI was performed in the axial plane, using a multisection single shot echo planar pulse sequence. The single voxel proton spectroscopy technique used was the point-resolved spectroscopy (PRESS) sequence with a TR of 1500 ms, short and long TE of 30/135 ms. RESULTS: The cysts presented similar signal intensity to the CSF on DWI, with comparable ADC values, ranging from 1.36 to 3.18 x 10-3 mm2/s. The detectable peaks were lactate (96.3%), succinate (48%), alanine (40%), lipids (15%), cytosolic amino acids (7.5%) and acetate (3.7%). CONCLUSION: The cysts of neurocysticercosis presented hyposignal on DWI and peaks of lactate, succinate, alanine, lipids, cytosolic amino acids and acetate in proton spectroscopy, in decreasing order of frequency

Les lésions résultantes d’un Accident Ischémique Cérébral (AIC) restent invisibles pendant plusieurs heures voire dizaines d’heures sur les techniques conventionnelles d’imagerie médicale (scanner X ou IRM). De nouvelles séquences d’IRM (pondérées en diffusion et en perfusion) permettent de visualiser les atteintes immédiatement. Les images de diffusion et de perfusion sont le reflet de mécanismes physiopathologiques complexes et contiennent aussi des informations sur le devenir tissulaire. Un modèle probabiliste d’évolution des lésions visibles au stade précoce a été développé de manière à prédire les extensions et rétrécissements des dommages. Le résultat se présente sous la forme d’une cartographie probabiliste de nécrose où la valeur de chaque voxel de l’image représente le risque de mort cellulaire au stade chronique. Cette cartographie pourra être, ensuite, prise en compte dans la décision thérapeutique. Deux types d’approche ont été mises en place : une méthode de segmentation, permettant d’extraire les régions à risque, et une méthode de prédiction des voxels à risque de nécrose, de type régression logistique. Ces modèles fournissent des performances similaires par rapport aux quelques modèles décrits dans la littérature, mais sont plus performants sur les petites lésions et présentent une grande amélioration en raison de leur caractère entièrement automatique / The lesions resulting from an ischemic stroke remain invisible for several hours or even tens of hours on conventional techniques of medical imaging (CT scan or MRI). New MRI sequences (diffusion-weighted and perfusion-weighted images) reveal the damages immediately. The diffusion and perfusion images reflect complex pathophysiological mechanisms and also contain some information on the fate of the tissue. A probabilistic model of evolution of the lesions visible at an early stage was set up so as to predict expansions and contractions of the damages. The result is presented as a probabilistic mapping of necrosis where the value of each voxel of the image represents the risk of cellular death in the chronic phase. This mapping can then be taken into account in the therapeutic decision. We implemented two types of approach: a segmentation method, allowing extracting regions atrisk, and a prediction method, type of logistic regression, to predict voxels at risk of necrosis. These models provide similar performances with regard to the few models described in the literature, but are more efficient for small lesions and show a big improvement because they are fully automatic