【摘 要】
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Metabolic information is essential in the investigation of the pathophysiology of stroke-like episodes in patients with mitochondrial encephalomyopathy,lactic acidosis,and stroke-like episodes (MELAS)
【机 构】
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Department of Neurology,Peking University First Hospital,Beijing,100034
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Metabolic information is essential in the investigation of the pathophysiology of stroke-like episodes in patients with mitochondrial encephalomyopathy,lactic acidosis,and stroke-like episodes (MELAS).Here,we used magnetic resonance imaging to evaluate the dynamic metabolic changes before and after a stroke-like episode in three patients with MELAS caused by the mitochondrial DNA mutation A3243G.We performed functional magnetic resonance imaging,including arterial spin labeling and oxygen extraction fraction (OEF) imaging,and generated cerebral blood flow and OEF maps.We recruited eight healthy volunteers to define the normal range of the oxygen extraction fraction.We detected a heterogeneous reduction in the OEF in the brain in the interictal period as well as at the onset of a stroke-like attack.However,the oxygen extraction fraction in the stroke-like lesions normalized in the acute stage.The stroke-like lesions showed consistent hyperperfusion in the acute phase but hypoperfusion in the chronic phase,which is consistent with previous studies.More importantly,we found that hyperemia pre-dated the new stroke-like lesions by one month in these patients.In conclusion,We have demonstrated the utility of using new magnetic resonance imaging techniques in the evaluation of the pathophysiology of stroke-like lesions.The increased utilization of oxygen in an acute lesion is a novel finding in our study,which might play a role in the oxidative stress.Moreover,hyperemia could be a predictive indicator of a new stroke-like attack,which need to be confirmed in more cases in future.
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