Significance: Intracranial pressure (ICP), variability in perfusion, and resulting ischemia are leading causes of secondary brain injury in patients treated in the neurointensive care unit. Continuous, accurate monitoring of cerebral blood flow (CBF) and ICP guide intervention and ultimately reduce morbidity and mortality. Currently, only invasive tools are used to monitor patients at high risk for intracranial hypertension. Aim: Diffuse correlation spectroscopy (DCS), a noninvasive near-infrared optical technique, is emerging as a possible method for continuous monitoring of CBF and critical closing pressure (CrCP or zero-flow pressure), a parameter directly related to ICP. Approach: We optimized DCS hardware and algorithms for the quantification of CrCP. Toward its clinical translation, we validated the DCS estimates of cerebral blood flow index (CBFi) and CrCP in ischemic stroke patients with respect to simultaneously acquired transcranial Doppler ultrasound (TCD) cerebral blood flow velocity (CBFV) and CrCP. Results: We found CrCP derived from DCS and TCD were highly linearly correlated (ipsilateral R2 = 0.77, p = 9 × 10 − 7; contralateral R2 = 0.83, p = 7 × 10 − 8). We found weaker correlations between CBFi and CBFV (ipsilateral R2 = 0.25, p = 0.03; contralateral R2 = 0.48, p = 1 × 10 − 3) probably due to the different vasculature measured. Conclusion: Our results suggest DCS is a valid alternative to TCD for continuous monitoring of CrCP.

中文翻译：

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脑卒中患者经颅多普勒超声临界闭合压力弥散相关谱测量的验证

意义：在神经重症监护病房接受治疗的患者中，颅内压 (ICP)、灌注变异和由此产生的缺血是继发性脑损伤的主要原因。持续、准确地监测脑血流量 (CBF) 和 ICP 指导干预并最终降低发病率和死亡率。目前，只有侵入性工具用于监测颅内高压高危患者。目的：漫相关光谱 (DCS) 是一种无创近红外光学技术，正在成为连续监测 CBF 和临界关闭压力（CrCP 或零流量压力）的一种可能方法，这是与 ICP 直接相关的参数。方法：我们优化了 DCS 硬件和算法以量化 CrCP。在临床翻译方面，我们根据同时获得的经颅多普勒超声 (TCD) 脑血流速度 (CBFV) 和 CrCP 验证了缺血性卒中患者脑血流指数 (CBFi) 和 CrCP 的 DCS 估计值。结果：我们发现来自 DCS 和 TCD 的 CrCP 高度线性相关（同侧 R2 = 0.77，p = 9 × 10 − 7；对侧 R2 = 0.83，p = 7 × 10 − 8）。我们发现 CBFi 和 CBFV 之间的相关性较弱（同侧 R2 = 0.25，p = 0.03；对侧 R2 = 0.48，p = 1 × 10 − 3）可能是由于测量的血管系统不同。结论：我们的结果表明 DCS 是 TCD 的有效替代品，可用于连续监测 CrCP。我们发现来自 DCS 和 TCD 的 CrCP 是高度线性相关的（同侧 R2 = 0.77，p = 9 × 10 − 7；对侧 R2 = 0.83，p = 7 × 10 − 8）。我们发现 CBFi 和 CBFV 之间的相关性较弱（同侧 R2 = 0.25，p = 0.03；对侧 R2 = 0.48，p = 1 × 10 − 3）可能是由于测量的血管系统不同。结论：我们的结果表明 DCS 是 TCD 的有效替代品，可用于连续监测 CrCP。我们发现来自 DCS 和 TCD 的 CrCP 是高度线性相关的（同侧 R2 = 0.77，p = 9 × 10 − 7；对侧 R2 = 0.83，p = 7 × 10 − 8）。我们发现 CBFi 和 CBFV 之间的相关性较弱（同侧 R2 = 0.25，p = 0.03；对侧 R2 = 0.48，p = 1 × 10 − 3）可能是由于测量的血管系统不同。结论：我们的结果表明 DCS 是 TCD 的有效替代品，可用于连续监测 CrCP。