Gao Wenpeng, Jiang Baichuan, Kacher Daniel F, Fetics Barry, Nevo Erez, Lee Thomas C, Jayender Jagadeesan
School of Life Science and Technology, Harbin Institute of Technology, Harbin, China.
Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Massachusetts, USA.
Int J Med Robot. 2018 Feb;14(1). doi: 10.1002/rcs.1871. Epub 2017 Nov 28.
A method of real-time, accurate probe tracking at the entrance of the MRI bore is developed, which, fused with pre-procedural MR images, will enable clinicians to perform cryoablation efficiently in a large workspace with image guidance.
Electromagnetic (EM) tracking coupled with optical tracking is used to track the probe. EM tracking is achieved with an MRI-safe EM sensor working under the scanner's magnetic field to compensate the line-of-sight issue of optical tracking. Unscented Kalman filter-based probe tracking is developed to smooth the EM sensor measurements when occlusion occurs and to improve the tracking accuracy by fusing the measurements of two sensors.
Experiments with a spine phantom show that the mean targeting errors using the EM sensor alone and using the proposed method are 2.21 mm and 1.80 mm, respectively.
The proposed method achieves more accurate probe tracking than using an EM sensor alone at the MRI scanner entrance.
开发了一种在MRI孔道入口处进行实时、精确探头跟踪的方法，该方法与术前MR图像融合，将使临床医生能够在大工作空间中借助图像引导有效地进行冷冻消融。
采用电磁（EM）跟踪与光学跟踪相结合的方式来跟踪探头。通过在扫描仪磁场下工作的MRI安全EM传感器实现EM跟踪，以补偿光学跟踪的视线问题。开发了基于无迹卡尔曼滤波器的探头跟踪方法，在发生遮挡时平滑EM传感器测量值，并通过融合两个传感器的测量值提高跟踪精度。
对脊柱模型进行的实验表明，单独使用EM传感器和使用所提方法时的平均靶向误差分别为2.21毫米和1.80毫米。
所提方法在MRI扫描仪入口处实现了比单独使用EM传感器更精确的探头跟踪。
