Department of Cardiovascular Sciences, Ageing and Stroke Medicine Group, University of Leicester NHS Trust, Gwendolen Road, Leicester, UK.
J Cereb Blood Flow Metab. 2011 May;31(5):1302-10. doi: 10.1038/jcbfm.2010.225. Epub 2010 Dec 29.
Cerebral autoregulation (CA) describes the mechanism responsible for maintaining cerebral blood flow (CBF) relatively constant, despite changes in mean arterial blood pressure (ABP). This paper introduces a novel method for assessing CA using magnetic resonance imaging (MRI). Images are rapidly and repeatedly acquired using a gradient-echo echo-planar imaging pulse sequence for a period of 4 minutes, during which a transient decrease in ABP is induced by rapid release of bilateral thigh cuffs. The method was validated by comparing the observed MRI signal intensity change with the CBF velocity change in the middle cerebral arteries, as measured by transcranial Doppler (TCD) ultrasound, using a standardized thigh cuff maneuver in both cases. Cross-correlation analysis of the response profiles from the left and right hemispheres showed a greater consistency for MRI measures than for TCD, both for interhemisphere comparisons and for repeated measures. The new MRI method may provide opportunities for assessing regional autoregulatory changes following acute stroke, and in other conditions in which poor autoregulation is implicated.
脑自动调节（CA）描述了一种机制，该机制负责在平均动脉血压（ABP）发生变化时，使脑血流量（CBF）保持相对稳定。本文介绍了一种使用磁共振成像（MRI）评估 CA 的新方法。使用梯度回波回波平面成像脉冲序列在 4 分钟的时间内快速重复采集图像，在此期间通过快速释放双侧大腿袖带引起 ABP 的短暂下降。通过将观察到的 MRI 信号强度变化与经颅多普勒（TCD）超声测量的大脑中动脉 CBF 速度变化进行比较，在两种情况下均使用标准的大腿袖带操作对该方法进行了验证。来自左右半球的响应曲线的互相关分析表明，对于 MRI 测量值，与 TCD 相比，无论是半球间比较还是重复测量，其一致性都更好。新的 MRI 方法可能为评估急性中风后以及在涉及自动调节不良的其他情况下的区域性自动调节变化提供机会。
