Background and objective

The manual measurement of arterial diameter and wall thickness using imaging modalities demand expertise, and the state-of-art automated or semi-automated measurement features are seldom available in the entry-level systems. The advanced ultrasound modalities are expensive, non-scalable, and less favorable for field and resource-constrained settings. In this work, we present a novel method to measure arterial diameter (D), surrogate intima-media thickness (sIMT), and with them their intra-cardiac cycle changes by employing an affordable image-free ultrasound technology.

Methods

The functionality of the method was systematically validated on a simulation testbed, phantoms and, 40 human subjects. The accuracy, agreement, inter-beat, and inter-operator variabilities were quantified. The in-vivo measurement performance of the method was compared against two reference B-mode tools – Carotid Studio and CAROLAB.

Results

Simulations revealed that for the A-mode frames with SNR > 10 dB, the proposed method identifies the desired arterial wall interfaces with an RMSE < 20 μm. The RMSE for the diameter and wall thickness measurements from the static phantom were 111 μm and 14 μm, and for the dynamic phantom were 117 μm and 18 μm, respectively. Strong agreement was seen between the in-vivo measurements of the proposed method and the two reference tools. The mean absolute errors against the two references and the inter-beat variability were smaller than 0.18 mm for D and smaller than 36 μm for sIMT measurements. Likewise, the respective inter-observer variabilities were 0.16 ± 0.23 mm and 43 ± 25 μm.

Conclusion

Acceptable accuracy and repeatability were observed during the validation, that were on a par with the recently reported B-mode techniques in the literature. The technology being real-time, automated, and relatively inexpensive, is promising for field and low-resource settings.

中文翻译：

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通过无图像超声自动测量动脉直径和壁厚的压缩-减压。

背景和目标

使用成像方式手动测量动脉直径和壁厚需要专业知识，而入门级系统很少提供最新的自动或半自动测量功能。先进的超声检查方式昂贵，不可扩展且对现场和资源受限的环境不利。在这项工作中，我们提出了一种新颖的方法来测量动脉直径（D），替代内膜中膜厚度（sIMT），并通过采用负担得起的无图像超声技术来改变它们的心内周期。

方法

该方法的功能已在模拟测试台，体模和40名人类受试者上得到了系统验证。准确性，一致性，节拍和操作员之间的差异进行了量化。将该方法的体内测量性能与两个参考B型工具– Carotid Studio和CAROLAB进行了比较。

结果

仿真显示，对于SNR> 10 dB的A模式帧，所提出的方法可以识别出期望的动脉壁界面，其RMSE <20μm。静态模型的直径和壁厚测量的RMSE分别为111μm和14μm，动态模型的RMSE分别为117μm和18μm。在所提出的方法的体内测量结果与两种参考工具之间发现了很强的一致性。相对于两个参考值的平均绝对误差和拍间变异性对于D小于0.18 mm，对于sIMT测量小于36μm。同样，观察者之间的差异分别为0.16±0.23 mm和43±25μm。

结论

在验证过程中观察到可接受的准确性和可重复性，与文献中最近报道的B模式技术相当。该技术是实时的，自动化的并且相对便宜，对于野外和资源匮乏的环境是有希望的。