Mokry Anna, Willmitzer Florian, Hostettler Rafael, Richter Henning, Kircher Patrick, Kneissl Sibylle, Wetzel Stephan
Clinical Unit of Diagnostic Imaging, Vetmeduni Vienna, Vienna, Austria.
Clinic for Diagnostic Imaging, Department of Clinical Diagnostics and Services, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
Neuroradiology. 2019 Jan;61(1):55-61. doi: 10.1007/s00234-018-2107-0. Epub 2018 Dec 1.
To describe the features of a novel patient-mounted system for CT-guided needle navigation, the Puncture Cube System (PCS), and to evaluate the accuracy and efficiency of the PCS by (a) applying numerical simulations and (b) by conducting punctures using the system in comparison to punctures using the free-hand method (FHM).
The PCS consists of a self-adhesive cube that is attached to the patient, with multiple through-holes in the upper and lower template plate and dedicated software that, using a computer vision algorithm, recognizes the cube in a planning scan. The target in the image dataset is connected by a line, here "virtual needle," which passes through the cube. For any chosen path of the virtual needle, the entry points for the needle into the cube are displayed by the software for the upper and lower template on-the-fly. The possible exactness of the system was investigated by using numerical simulations. Next, 72 punctures were performed by 6 interventionists using a phantom to compare for accuracy, time requirement, and number of CT scans for punctures with the system to the FHM ex vivo (phantom study).
The theoretical precision to arrive at targets increased with the distance of the target but remained low. The mean error for targets up to 20 cm below the lower plate was computed to be well below 0.5 mm, and the worst-case error stayed below 1.3 mm. Compared to a conventional free-hand procedure, the use of the navigation system resulted in a statistically significantly improved accuracy (3.4 mm ± 2.3 mm versus FHM 4.9 mm ± 3.2 mm) and overall lower intervention time (168 s ± 28.5 s versus FHM 200 s ± 44.8 s). Furthermore, the number of CT scans was reduced to 2.3 versus FHM 2.8).
The PCS is a promising technique to improve accuracy and reduce intervention time in CT-guided needle navigations compared to the FHM.
描述一种新型的用于CT引导下针穿刺导航的患者安装系统——穿刺立方体系统（PCS）的特点，并通过（a）进行数值模拟和（b）使用该系统进行穿刺并与徒手穿刺方法（FHM）进行比较，来评估PCS的准确性和效率。
PCS由一个粘贴在患者身上的自粘立方体组成，上下模板板上有多个通孔，以及专用软件，该软件使用计算机视觉算法在规划扫描中识别立方体。图像数据集中的目标通过一条线（此处为“虚拟针”）连接，该线穿过立方体。对于虚拟针的任何选定路径，软件会实时显示针进入立方体的上、下模板的入口点。通过数值模拟研究了该系统可能的精确性。接下来，6名介入医生使用模型进行了72次穿刺，以比较该系统与FHM在体外穿刺（模型研究）时的准确性、时间要求和CT扫描次数。
到达目标的理论精度随目标距离增加而提高，但仍较低。计算得出，在下模板下方20厘米以内的目标的平均误差远低于0.5毫米，最坏情况下的误差低于1.3毫米。与传统的徒手操作相比，使用导航系统在统计学上显著提高了准确性（3.4毫米±2.3毫米，而FHM为4.9毫米±3.2毫米），并且总体干预时间更短（168秒±28.5秒，而FHM为200秒±44.8秒）。此外，CT扫描次数减少到2.3次，而FHM为2.8次。
与FHM相比，PCS是一种有前景的技术，可提高CT引导下针穿刺导航的准确性并减少干预时间。
