Martini Ziekenhuis Groningen, Post Box 30.033, 9700 RM, Groningen, The Netherlands.
J Neurosci Methods. 2018 Sep 1;307:1-7. doi: 10.1016/j.jneumeth.2018.06.009. Epub 2018 Jun 18.
For the interpretation of middle cerebral artery flow velocity (MCAFV) measurements by transcranial Doppler clinicians should take normal aging into account.
MCAFV measurements can be corrected for age by a transformation to Z-scores, expressing in standard deviations the distance of a measurement to the regression line as function of age. Z-scores for different parameters can be combined into a single plot in order to facilitate clinical interpretation.
In a retrospective analysis 41 subjects were identified with normal autonomic responses, normal CO2-reactivity and satisfactory transcranial Doppler data. Age related changes were determined for: maximal change in flow velocity (FV) during stroke onset (Acc), maximal FV during the first (Sys1) and second phase (Sys2) of systole and mean diastolic FV 560 ms after stroke onset (Dias@560). Patients were supine and breathing normally. Sys1, Sys2 and Dias@560 decreased significantly with age: -0.58 cm/s/yr, -0.36 cm/s/yr. and -0.38 cm/s/yr., respectively. Sys1 decreased more rapidly than Sys2 and Dias@560 so that in the young the MCAFV signal is more Sys1 dominant, whereas in the elderly it becomes more Sys2 prevalent. The effect of CO2-reactivity was assessed by transformation to Z-scores and combining different parameters within a single radar plot.
In contrast to standard MCAFV measurements the calculation of Z-scores takes aging into account and standardizes the signal variation.
Graphically combining Z-scores for different MCAFV parameters makes the signal more accessible for rapid clinical interpretation.
经颅多普勒医师在解读大脑中动脉血流速度（MCAFV）测量值时，应考虑正常衰老因素。
MCAFV 测量值可通过转换为 Z 分数进行年龄校正，以标准偏差表示测量值与年龄相关回归线的距离。不同参数的 Z 分数可以组合到单个图中，以便于临床解释。
在回顾性分析中，确定了 41 例具有正常自主神经反应、正常 CO2 反应性和满意经颅多普勒数据的受试者。确定了与年龄相关的变化：在发作期间血流速度（FV）的最大变化（Acc）、收缩期第一阶段（Sys1）和第二阶段（Sys2）的最大 FV 以及发作后 560ms 的平均舒张期 FV（Dias@560）。患者仰卧并正常呼吸。Sys1、Sys2 和 Dias@560 随年龄显著下降：-0.58cm/s/yr、-0.36cm/s/yr 和-0.38cm/s/yr。Sys1 的下降速度快于 Sys2 和 Dias@560，因此在年轻人中 MCAFV 信号更偏向于 Sys1，而在老年人中则更偏向于 Sys2。通过转换为 Z 分数并在单个雷达图中组合不同参数来评估 CO2 反应性的影响。
与标准 MCAFV 测量值相比，Z 分数的计算考虑了年龄因素，并使信号变化标准化。
组合不同 MCAFV 参数的 Z 分数使信号更易于快速临床解释。
