Longitudinal thalamic diffusion changes after middle cerebral artery infarcts
Longitudinal thalamic diffusion changes after middle cerebral artery infarcts
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DOI：
10.1136/jnnp.2004.041012
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发表时间：
2005-02-01
影响因子：
11
通讯作者：
Chabriat, H
中科院分区：
文献类型：
--
作者：
Hervé, D;Molko, N;Chabriat, H
背景：脑梗塞在距离缺血区较远的地方引起功能改变和微观组织损伤。这种远程影响已经涉及到中风的康复。丘脑低代谢与大脑中动脉(MCA)梗死的运动恢复有关，但对这些代谢变化背后的组织变化知之甚少。弥散张量成像(DTI)对大脑中动脉梗死后的微结构改变高度敏感，可用于在体定量显示大脑中动脉梗死后丘脑的纵向微观组织改变。结果：卒中后1~6个月，同侧丘脑平均弥散系数(MD)、各向异性分数(FA)和丘脑区体积明显增加(0.766×10(-3)mm(2)/S 1个月；0.792×10(-3)mm(2)/S 3个月；0.806×10(-3)mm(2)/S 6个月)。未检测到对FA有明显的修饰作用。在6例患者中，同侧/对侧MD指数高于10名年龄匹配的对照组计算的95%CI上限。1例患者在发病第1周和2例患者在1个月时同侧丘脑弥散增加之前，MD早期降低。结论：大脑中动脉梗死后，DTI在卒中后1个月观察到同侧丘脑弥散增加。这可能是因为神经元和/或神经胶质细胞的进行性丧失。在一些患者中，在这种增加之前，扩散的一过性下降可能与这些细胞的早期肿胀或小胶质细胞的激活有关。需要进行更大系列的进一步研究来评估这些发现的临床相关性。
Background: Cerebral infarcts are responsible for functional alterations and microscopic tissue damage at distance from the ischaemic area. Such remote effects have been involved in stroke recovery. Thalamic hypometabolism is related to motor recovery in middle cerebral artery ( MCA) infarcts but little is known concerning the tissue changes underlying these metabolic changes. Diffusion tensor imaging ( DTI) is highly sensitive to microstructural tissue alterations and can be used to quantify in vivo the longitudinal microscopic tissue changes occurring in the thalamus after MCA infarcts in humans.Methods: Nine patients underwent DTI after an isolated MCA infarct. Mean diffusivity ( MD), fractional anisotropy ( FA), and thalamic region volume were measured from the first week to the sixth month after stroke onset in these patients and in 10 age matched controls.Results: MD significantly increased in the ipsilateral thalamus between the first and the sixth month ( 0.766 x 10(-3) mm(2)/ s first month; 0.792 x 10(-3) mm(2)/ s third month; 0.806 x 10(-3) mm(2)/ s sixth month). No significant modification of FA was detected. In six patients, the ipsilateral/ contralateral index of MD was higher than the upper limit of the 95% CI calculated in 10 age matched controls. An early decrease of MD preceded the increase of ipsilateral thalamic diffusion in one patient at the first week and in two other patients at the first month.Conclusion: After MCA infarcts, an increase in diffusion is observed with DTI in the ipsilateral thalamus later than 1 month after the stroke onset. This is presumably because of the progressive loss of neurons and/ or glial cells. In some patients, this increase is preceded by a transient decrease in diffusion possibly related to an early swelling of these cells or to microglial activation. Further studies in larger series are needed to assess the clinical correlates of these findings.