SNR - Artigos publicados em revistas indexadas na Pubmed/Medline
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Browsing SNR - Artigos publicados em revistas indexadas na Pubmed/Medline by Author "Carneiro, A."
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- Acute ischemic stroke secondary to glioblastoma. A case reportPublication . Pina, S.; Carneiro, A.; Rodrigues, T.; Samões, R.; Taipa, R.; Melo-Pires, M.; Pereira, C.Glioblastoma is a malignant infiltrative glial tumor occurring most often over 50 years of age, with diverse clinical presentations. We describe a case of temporal lobe glioblastoma with a rare presentation as an acute ischemic stroke, discussing the imaging and histopathological findings, and reviewing the literature. A 77-year-old woman had sudden onset of left hemiparesis and hemihypoesthesia. The neuroradiological studies revealed an acute ischemic lesion in the right lenticulostriate arteries territory and a right anterior temporal lobe tumor, enhancing heterogeneously after contrast with enhancement of the right middle cerebral artery wall. Histopathological analysis of the resected temporal lesion revealed a glioblastoma multiforme with tumoral infiltration of the vascular wall. Glioblastoma should be considered in the etiology of acute ischemic stroke, where neuroimaging plays an important diagnostic role, enabling a more immediate therapeutic approach, with a consequent impact on survival.
- Arterial Spin Labeling: Experiência Inicial, Indicações Clínicas e DificuldadesPublication . Carneiro, A.; Pina, S.; Moreira, B.RESUMO O arterial spin labeling (ASL) é uma técnica de perfusão por ressonância magnética (RM) que usa os protões das moléculas de água do sangue arterial como marcador endógeno. As suas principais vantagens residem no facto de ser um método não invasivo, rápido e que dispensa a administração de contraste. Actualmente os seus resultados são reprodutíveis de modo robusto, o que o torna uma ferramenta cada vez mais utilizada na prática clínica. O objectivo deste trabalho é apresentar a nossa experiência inicial com o ASL, salientando os aspectos técnicos, as principais solicitações clínicas, os resultados obtidos e as dificuldades experimentadas. Métodos: Foi efectuada uma revisão dos exames realizados durante um período de oito meses, usando uma técnica de ASL pulsado, num aparelho de 3T. A avaliação dos mapas de perfusão foi realizada de modo qualitativo. Resultados: As principais indicações clínicas para a realização de ASL foram epilepsia, doenças neuro-degenerativas e tumores intra-parenquimatosos. Embora o ASL não tenha sido, em nenhum dos casos, a principal ferramenta diagnóstica, contribuiu, por vezes, com dados fisiológicos importantes para o diagnóstico e para a orientação terapêutica. Salientam-se os casos de doentes com múltiplas crises epilépticas nos quais foi possível identificar focos de hiperperfusão pós-ictal (cujos resultados foram concordantes com o SPECT). Destacam-se ainda casos de doenças neuro-degenerativas nos quais o ASL identificou áreas de hipoperfusão típicas das respectivas entidades nosológicas. As principais dificuldades estiveram relacionadas com o carácter qualitativo da avaliação e com a valorização clínica dos achados. Conclusão: O estudo da perfusão cerebral por ASL tem um potencial diagnóstico importante. Com este trabalho mostramos que, com uma aquisição rápida e pós-processamento simples, pode facilmente integrar os estudos de RM de rotina. Abstract Arterial spin labelling (ASL) is a MR perfusion technique that uses protons from water molecules of the arterial blood as an endogenous tracer. It is fast, non-invasive and does not require gadolinium administration. Due to the increasing robustness of the results, it is becoming an important clinical tool. In this article we present our initial experience with ASL, highlighting some technical aspects, the main clinical applications, some achieved results and most important difficulties. Methods: Review of the examinations performed during eight months, using a pulsating ASL technique in a 3T machine. Perfusion maps were evaluated qualitatively. Results: The most frequent clinical applications were epilepsy, neurodegenerative disorders and tumours. Although perfusion data from ASL had never been crucial for diagnosis, it still provided substantial information. We highlight two epileptic patients who had had recent seizures, in which ASL depicted distinct post-ictal hyperperfusion areas (with the results being confirmed by SPECT studies). The impact was also remarkable in patients with neurodegenerative disorders in which ASL depicted hypoperfusion areas, typical of each nosological entity. The main difficulties were related to the lack of quantitative evaluation and to the clinical interpretation of the results obtained. Conclusion: ASL perfusion studies have a great potential in several clinical conditions. In this article we show that, with a fast acquisition and easy post-processing, it can integrate routine MRI examinations.
- Mechanical thrombectomy in patients with acute basilar occlusion using stent retrieversPublication . Carneiro, A.; Rodrigues, J.; Pereira, J.; Alves, J.; Xavier, J.Early arterial recanalisation with stent retrievers (SR) has been recently demonstrated to improve clinical outcome of patients with large-vessel occlusion of the anterior circulation. However, the benefit of SR thrombectomy in the setting of acute basilar artery occlusion (BAO) has not been proven yet. This study evaluated a series of consecutive patients with BAO treated with SR, focusing on the efficacy, safety and clinical results.
- Reliability of CT perfusion in the evaluation of the ischaemic penumbraPublication . Alves, J.; Carneiro, A.; Xavier, J.CT perfusion (CTP) is part of the initial evaluation of stroke patients, allowing differentiation between infarcted tissue and the ischaemic penumbra and helping in the selection of patients for endovascular treatment. This study assessed the reliability of the qualitative evaluation CTP maps in defining the ischemic penumbra and identified potential pitfalls associated with this technique. We reviewed CTP scans of 45 consecutive patients admitted to our institution with anterior circulation acute ischaemic stroke. Two neuroradiologists performed qualitative evaluations of cerebral blood volume (CBV) and mean transit time (MTT) maps, using 24h follow-up non-contrast CT as surrogate marker for the area of definitive infarct. For each slice analyzed, the area of qualitative alteration in the CBV and MTT maps was classified as either being inferior, equal or superior to the area of infarct on the follow-up CT. Three out of 45 (7%) patients had admission CT CBV abnormalities larger than follow-up lesions; 34/45 (76%) patients had infarct areas smaller than initial MTT prolongation. In the group of patients with no recanalization 12/19 (63%) had infarct areas smaller than initial MTT lesion. CBV abnormality is a reliable marker for an irreversible ischaemic lesion, although rarely it may overestimate the ischaemic "core", possibly due to delay in contrast arrival to the brain. In the majority of patients without recanalization, MTT overestimated final infarct areas, probably because it does not differentiate true "at risk" penumbra from benign oligaemia. Qualitative evaluation of CBV and MTT maps may overestimate the real ischaemic penumbra.
- Response to letter to the editor. "CT angiography source-images and CT perfusion: are they complementary tools for ischemic stroke evaluation?"Publication . Alves, J.; Carneiro, A.; Xavier, J.