RESUMO
We investigated the number and possible causes of clinically silent lesions seen in diffusion-weighted magnetic resonance imaging after embolization of arteriovenous malformations (AVMs) and fistulas using acrylate only or in combination with coils. Included were 19 patients with 18 AVMs and one case of a vein of Galen aneurysm in which 25 interventions were carried out. Results of diffusion-weighted imaging, the appearance of perinidal and distant lesions, were correlated to Spetzler grade, nidus size, flow, number of feeders occluded, rate of nidus occlusion and duration of the intervention. We found seven distant lesions corresponding to non-symptomatic infarcts in the given clinical setting. The only significant correlation between lesion size and parameters analyzed was the degree of nidus occlusion achieved during the intervention. Because most of the lesions presented in cases with a high occlusion rate, they appear to be related to the intention to reach a complete occlusion of the nidus. These results emphasize that the risk involved in eliminating the nidus completely must be reconsidered with special care, particularly in a situation where most high-flow feeders have been occluded.
Assuntos
Fístula Arteriovenosa/terapia , Infarto Cerebral/etiologia , Infarto Cerebral/patologia , Imagem de Difusão por Ressonância Magnética , Embolização Terapêutica/efeitos adversos , Malformações Arteriovenosas Intracranianas/terapia , Adolescente , Adulto , Fístula Arteriovenosa/complicações , Fístula Arteriovenosa/patologia , Criança , Feminino , Humanos , Malformações Arteriovenosas Intracranianas/complicações , Malformações Arteriovenosas Intracranianas/patologia , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento , Adulto JovemRESUMO
BACKGROUND: In a variety of dystonias, functional magnetic resonance imaging has shown deviations of cortical and basal ganglia activations within the motor network, which might cause the movement disturbances. Because these investigations have never been performed in secondary dystonia due to Pantothenate-Kinase Associated Neurodegeneration, we report our results in a small group of such patients from the Dominican Republic. METHODS: Functional magnetic resonance imaging was carried out in 7 patients with a genetically confirmed mutation of the PANK2 gene and a non-affected control group (matched pairs) using an event-related motor activation paradigm (hand movements). RESULTS: Compared to the control group (p ≤ 0.01), patients showed a larger amount of activated voxels starting in the contralateral cerebellum and contralateral premotor cortex 2 s before the actual hand movement. Whereas these "hyperactivations" gradually diminished over time, activations in the contralateral primary motor cortex and the supplementary motor area peaked during the next second and those of the contralateral putamen at the time of the actual hand movement. In a multiple regression analysis, all these areas correlated positively with the degree of dystonia of the contralateral arm as judged by the Burke-Fahn-Marsden-scale (p ≤ 0.001). CONCLUSION: As in other forms of dystonia, the increased activations of the motor system found in our patients could be related to the origin of the dystonic movements. Because in this condition the primary lesion affects the pallidum, a defect of the feed-back control mechanism between basal ganglia and cortex might be the responsible factor.
Assuntos
Cerebelo/irrigação sanguínea , Imageamento por Ressonância Magnética , Córtex Motor/irrigação sanguínea , Movimento/fisiologia , Neurodegeneração Associada a Pantotenato-Quinase/patologia , Neurodegeneração Associada a Pantotenato-Quinase/fisiopatologia , Adolescente , Mapeamento Encefálico , Estudos de Casos e Controles , Cerebelo/fisiopatologia , Feminino , Mãos/fisiopatologia , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Córtex Motor/fisiopatologia , Oxigênio/sangue , Adulto JovemRESUMO
The assessment of shunt reduction after an embolization of an arteriovenous malformation (AVM) or fistula (AVF) from conventional angiography is often difficult and may be subjective. Here we present a completely non-invasive method using magnetic resonance imaging (MRI) to measure shunt reduction. Using pulsed arterial spin labeling (PASL), we determined the relative amount of signal attributed to the shunt over 1.75 s and 6 different slices covering the lesion. This amount of signal from the shunt was related to the total signal from all slices and measured before and after embolization. The method showed a fair agreement between the PASL results and the judgement from conventional angiography. In the case of a total or subtotal shunt occlusion, PASL showed a shunt reduction between 69% and 92%, whereas in minimal shunt reduction as judged by conventional angiography, the ASL result was -6% (indicating slightly increased flow) to 35% in a partially occluded vein of Galen aneurysm. The PASL method proved to be fairly reproducible (up to 2% deviation between three measurements without interventions). On conclusion, PASL is able to reliably measure the amount of shunt reduction achieved by embolization of AVMs and AVFs.