Barva M, Uhercik M, Mari J M, Kybic J, Duhamel J R, Liebgott H, Hlavac V, Cachard C
Center for Machine Perception, Czech Tech. Univ. in Prague, Prague, Czech Republic.
IEEE Trans Ultrason Ferroelectr Freq Control. 2008 Jul;55(7):1559-69. doi: 10.1109/TUFFC.2008.833.
In surgical practice, small metallic instruments are frequently used to perform various tasks inside the human body. We address the problem of their accurate localization in the tissue. Recent experiments using medical ultrasound have shown that this modality is suitable for real-time visualization of anatomical structures as well as the position of surgical instruments. We propose an image-processing algorithm that permits automatic estimation of the position of a line-segment-shaped object. This method was applied to the localization of a thin metallic electrode in biological tissue. We show that the electrode axis can be found through maximizing the parallel integral projection transform that is a form of the Radon transform. To accelerate this step, hierarchical mesh-grid algorithm is implemented. Once the axis position is known, localization of the electrode tip is performed. The method was tested on simulated images, on ultrasound images of a tissue mimicking phantom containing a metallic electrode, and on real ultrasound images from breast biopsy. The results indicate that the algorithm is robust with respect to variations in electrode position and speckle noise. Localization accuracy is of the order of hundreds of micrometers and is comparable to the ultrasound system axial resolution.
在外科手术实践中，小型金属器械经常用于在人体内执行各种任务。我们解决它们在组织中精确定位的问题。最近使用医学超声的实验表明，这种模态适用于解剖结构以及手术器械位置的实时可视化。我们提出一种图像处理算法，该算法允许自动估计线段状物体的位置。此方法应用于生物组织中细金属电极的定位。我们表明，通过最大化作为拉东变换形式的平行积分投影变换可以找到电极轴。为加速这一步骤，实施了分层网格算法。一旦知道轴的位置，就进行电极尖端的定位。该方法在模拟图像、含有金属电极的组织模拟体模的超声图像以及乳腺活检的真实超声图像上进行了测试。结果表明，该算法对于电极位置变化和斑点噪声具有鲁棒性。定位精度约为数百微米，与超声系统轴向分辨率相当。
