Lindseth Frank, Langø Thomas, Bang Jon, Nagelhus Hernes Toril A
SINTEF Unimed, Ultrasound, Trondheim, Norway.
Comput Aided Surg. 2002;7(4):197-222. doi: 10.1002/igs.10046.
We have investigated the 3D navigation accuracy of a frameless ultrasound-based neuronavigation system (SonoWand) for surgical planning and intraoperative image guidance. In addition, we present a detailed description and review of the error sources associated with surgical neuronavigation based on preoperative MRI data and intraoperative ultrasound. A phantom with 27 precisely defined points was scanned with ultrasound by various translation and tilt movements of the ultrasound probe (180 3D scans in total), and the 27 image points in each volume were located using an automatic detection algorithm. These locations were compared to the physically measured locations of the same 27 points. The accuracy of the neuronavigation system and the effect of varying acquisition conditions were found through a thorough statistical analysis of the differences between the two point sets. The accuracy was found to be 1.40 +/- 0.45 mm (arithmetic mean) for the ultrasound-based neuronavigation system in our laboratory setting. Improper probe calibration was the major contributor to this figure. Based on our extensive data set and thorough evaluation, the accuracy found in the laboratory setting is expected to be close to the overall clinical accuracy for ultrasound-based neuronavigation. Our analysis indicates that the overall clinical accuracy may be as low as 2 mm when using intraoperative imaging to compensate for brain shift.
我们研究了一种基于无框架超声的神经导航系统（SonoWand）用于手术规划和术中图像引导的三维导航准确性。此外，我们还对基于术前MRI数据和术中超声的手术神经导航相关误差源进行了详细描述和综述。使用超声探头通过各种平移和倾斜运动对具有27个精确定义点的体模进行扫描（总共180次三维扫描），并使用自动检测算法定位每个容积中的27个图像点。将这些位置与相同27个点的物理测量位置进行比较。通过对两组点之间差异的全面统计分析，得出神经导航系统的准确性以及不同采集条件的影响。在我们的实验室环境中，基于超声的神经导航系统的准确性为1.40±0.45毫米（算术平均值）。探头校准不当是造成这一数值的主要原因。基于我们广泛的数据集和全面评估，预计在实验室环境中发现的准确性接近基于超声的神经导航的总体临床准确性。我们的分析表明，当使用术中成像来补偿脑移位时，总体临床准确性可能低至2毫米。
