SIGNIFICANCE Noninvasive in vivo fast pulsatile blood flow measurement in deep tissue is important because the blood flow waveform is correlated with physiological parameters, such as blood pressure and elasticity of blood vessels. Compromised blood flow may cause diseases, such as stroke, foot ulcer, and myocardial ischemia. There is great clinical demand for a portable and cost-effective device for noninvasive pulsatile blood flow measurement. AIM A diffuse-optics-based method, diffuse speckle pulsatile flowmetry (DSPF), was developed for fast measurement (∼300  Hz) of deep tissue blood flow noninvasively. To validate its performance, both a phantom experiment and in vivo demonstration were conducted. APPROACH Over the past two decades, single-mode fibers have been used as detection fibers in most diffuse-optics-based deep tissue blood flow measurement modalities. We used a multimode (MM) detection fiber with a core size of 200  μm for diffused speckle pattern detection. A background intensity correction algorithm was implemented for speckle contrast calculation. The MM detection fiber helped to achieve a level of deep tissue blood flow measurement similar to that of conventional modalities, such as diffuse correlation spectroscopy and diffuse speckle contrast analysis, but it increases the measurement rate of blood flow to 300 Hz. RESULTS The design and implementation of the DSPF system were introduced. The theory of the background intensity correction for the diffused speckle pattern detected by the MM fiber was explained. A flow phantom was built for validation of the performance of the DSPF system. An in vivo cuff-induced occlusion experiment was performed to demonstrate the capability of the proposed DSPF system. CONCLUSIONS An MM detection fiber can help to achieve fast (∼300  Hz) pulsatile blood flow measurement in the proposed DSPF method. The cost-effective device and the fiber-based flexible probe increase the usability of the DSPF system significantly.

中文翻译：

---

通过多模检测光纤在深层组织中快速测量脉动血流。

意义深部组织中的无创体内快速脉动血流测量很重要，因为血流波形与生理参数相关，例如血压和血管弹性。血流受损可能会导致中风、足部溃疡和心肌缺血等疾病。对于用于无创脉动血流测量的便携式且具有成本效益的设备存在巨大的临床需求。目的 开发了一种基于扩散光学的方法，即扩散散斑脉动流量测量 (DSPF)，用于无创快速测量 (~300 Hz) 深部组织血流。为了验证其性能，进行了幻影实验和体内演示。方法 在过去的二十年里，单模光纤已被用作大多数基于漫射光学的深部组织血流测量模式中的检测光纤。我们使用纤芯尺寸为 200 μm 的多模 (MM) 检测光纤进行扩散散斑图案检测。为散斑对比度计算实施了背景强度校正算法。MM 检测光纤有助于实现与传统模式（如扩散相关光谱和扩散散斑对比分析）相似的深层组织血流测量水平，但它将血流测量速率提高到 300 Hz。结果介绍了DSPF系统的设计与实现。解释了对多模光纤检测到的散斑图案背景强度校正的理论。为了验证 DSPF 系统的性能，构建了一个流动模型。进行了体内袖带诱导的闭塞实验，以证明所提出的 DSPF 系统的能力。结论 MM 检测光纤有助于在所提出的 DSPF 方法中实现快速（~300 Hz）脉动血流测量。经济高效的设备和基于光纤的灵活探头显着提高了 DSPF 系统的可用性。