The key for safe ultrasound (US)-guided punctures is a good visibility of the cannula. When using convex transducers for deep punctures, the incident angle between US beam and cannula varies along the cannula leading to a complex visibility pattern. Here, we present a method to systematically investigate the visibility throughout the US image. For this, different objective criteria were defined and applied to measurement series with varying puncture angles and depths of the cannula. It is shown that the visibility not only depends on the puncture angle but also on the location of the cannula in the US image when using convex transducers. In some image regions, an unexpected good visibility was observed even for steep puncture angles. The systematic evaluation of the cannula visibility is of fundamental interest to sensitise physicians to the handling of convex transducers and to evaluate new techniques for further improvement.

中文翻译：

---

使用凸面超声换能器对套管的超声可见度

安全超声 (US) 引导穿刺的关键是套管的良好可见性。当使用凸面传感器进行深穿刺时，超声束和套管之间的入射角沿套管变化，导致复杂的可见性模式。在这里，我们提出了一种方法来系统地研究整个美国图像的可见性。为此，定义了不同的客观标准并将其应用于具有不同穿刺角度和套管深度的测量系列。结果表明，当使用凸面传感器时，可见度不仅取决于穿刺角度，还取决于美国图像中套管的位置。在某些图像区域，即使是陡峭的穿刺角度，也观察到了意想不到的良好可见度。