Division of Neuroradiology, Joint Department of Medical Imaging, Toronto Western Hospital, The University of Toronto, Toronto, ON M5T 2S8, Canada.
Brain. 2011 Jan;134(Pt 1):100-9. doi: 10.1093/brain/awq286. Epub 2010 Nov 24.
Epileptic seizures are a common presentation in patients with newly diagnosed brain arteriovenous malformations, but the pathophysiological mechanisms causing the seizures remain poorly understood. We used magnetic resonance imaging-based quantitative cerebrovascular reactivity mapping and conventional angiography to determine whether seizure-prone patients with brain arteriovenous malformations exhibit impaired cerebrovascular reserve or morphological angiographic features predictive of seizures. Twenty consecutive patients with untreated brain arteriovenous malformations were recruited (10 with and 10 without epileptic seizures) along with 12 age-matched healthy controls. Blood oxygen level-dependent MRI was performed while applying iso-oxic step changes in end-tidal partial pressure of CO(2) to obtain quantitative cerebrovascular reactivity measurements. The brain arteriovenous malformation morphology was evaluated by angiography, to determine to what extent limitations of arterial blood supply or the presence of restricted venous outflow and tissue congestion correlated with seizure susceptibility. Only patients with seizures exhibited impaired peri-nidal cerebrovascular reactivity by magnetic resonance imaging (0.11 ± 0.10 versus 0.25 ± 0.07, respectively; P < 0.001) and venous drainage patterns suggestive of tissue congestion on angiography. However, cerebrovascular reactivity changes were not of a magnitude suggestive of arterial steal, and were probably compatible with venous congestion in aetiology. Our findings demonstrate a strong association between impaired peri-nidal cerebrovascular reserve and epileptic seizure presentation in patients with brain arteriovenous malformation. The impaired cerebrovascular reserve may be associated with venous congestion. Quantitative measurements of cerebrovascular reactivity using blood oxygen level-dependent MRI appear to correlate with seizure susceptibility in patients with brain arteriovenous malformation.
新诊断的脑动静脉畸形患者常出现癫痫发作，但导致癫痫发作的病理生理机制仍知之甚少。我们使用基于磁共振成像的定量脑血管反应性测绘和常规血管造影来确定是否易发生癫痫的脑动静脉畸形患者存在脑血管储备受损或可预测癫痫发作的形态学血管造影特征。我们招募了 20 例未经治疗的脑动静脉畸形患者（10 例有癫痫发作，10 例无癫痫发作），并招募了 12 名年龄匹配的健康对照者。通过施加终末 CO2 分压的等氧阶跃变化来进行血氧水平依赖性 MRI，以获得定量脑血管反应性测量值。通过血管造影评估脑动静脉畸形的形态，以确定动脉供血受限的程度或存在限制的静脉流出和组织充血与易感性的相关性。只有癫痫发作的患者表现出磁共振成像的围瘤周脑血管反应性受损（分别为 0.11 ± 0.10 和 0.25 ± 0.07，P < 0.001）和血管造影提示静脉引流模式提示组织充血。然而，脑血管反应性的变化没有提示动脉窃血的程度，并且可能与病因中的静脉充血相容。我们的研究结果表明，脑动静脉畸形患者围瘤周脑血管储备受损与癫痫发作之间存在很强的关联。脑血管储备受损可能与静脉充血有关。使用血氧水平依赖性 MRI 进行的脑血管反应性定量测量似乎与脑动静脉畸形患者的癫痫发作易感性相关。
