Janorschke Christian, Popescu Sorin S, Osburg Jonas, Lu Xinyu, Xie Jingyang, Yaman Engin, Marquetand Christoph, Blanck Oliver, Alessandrini Hannes, Schweikard Achim, Tilz Roland R
Institute of Robotics and Cognitive Systems, University of Lübeck, Ratzeburger Allee 160, Lübeck, 23652, Germany.
Department of Rhythmology, University Heart Center Lübeck, University Hospital Schleswig-Holstein, Ratzeburger Allee 160, Lübeck, 23652, Germany.
Int J Comput Assist Radiol Surg. 2025 Sep 5. doi: 10.1007/s11548-025-03510-1.
Ultrasound (US) is commonly used to assess left ventricular motion for examination of heart function. In stereotactic arrhythmia radioablation (STAR) therapy, managing cardiorespiratory motion during radiation delivery requires representation of motion information in computed tomography (CT) coordinates. Similar to conventional US-guided navigation during surgical procedures, 3D US can provide real-time motion data of the radiation target that could be transferred to CT coordinates and then be accounted for by the radiation system. A motion analysis framework is presented that covers all necessary components to capture and analyse US motion data and transfer it to CT coordinates.
Utilizing a robotic test set-up with a human phantom, a baseline and ground truth dataset is recorded for the development and implementation of the motion analysis framework. An optical tracking system and an additional spatial calibration phantom are used to determine necessary transformations. Methods for frame matching, calibration, registration and evaluation are implemented.
The hardware set-up meets all requirements, including a frame rate exceeding 20 Hz and acceptable image quality, while involving only a few components that can easily be mounted and dismantled in a clinical context.The recorded phantom dataset meets all hardware-specific requirements including a frame rate exceeding 20 Hz, an offset between CT trigger time and the closest US recording of 2-20 ms as well as acceptable US image quality. The static phantom allows for quantitative evaluation by matching structures from different US frames in CT coordinates. While each individual step of the US and CT fusion process achieves the target accuracy of less than 5 mm error, the cumulative error over all transformations exceeded this limit for extreme probe positions.
The framework is developed and tested for the MATRIX-VT study and can be utilized for patient data evaluation as well as for transferring information such as positional data of moving anatomical structures between US and CTpredictive motion management in STAR therapy. Its modular design allows for the incorporation of advanced calibration and registration methods to address probe positioning limitations, thereby enhancing overall system performance for future applications.
超声（US）常用于评估左心室运动以检查心脏功能。在立体定向心律失常射频消融（STAR）治疗中，在放射治疗期间管理心肺运动需要在计算机断层扫描（CT）坐标中表示运动信息。与手术过程中传统的超声引导导航类似，三维超声可以提供放射治疗靶点的实时运动数据，这些数据可以转换为CT坐标，然后由放射治疗系统进行处理。本文提出了一个运动分析框架，该框架涵盖了捕获和分析超声运动数据并将其转换为CT坐标所需的所有组件。
利用带有人体模型的机器人测试装置，记录基线和真实数据集，用于运动分析框架的开发和实施。使用光学跟踪系统和额外的空间校准模型来确定必要的变换。实现了帧匹配、校准、配准和评估方法。
硬件设置满足所有要求，包括帧率超过20Hz和可接受的图像质量，同时仅涉及少数几个在临床环境中易于安装和拆卸的组件。记录的模型数据集满足所有硬件特定要求，包括帧率超过20Hz、CT触发时间与最近的超声记录之间的偏移为2 - 20毫秒以及可接受的超声图像质量。静态模型允许通过在CT坐标中匹配来自不同超声帧的结构进行定量评估。虽然超声和CT融合过程的每个单独步骤都实现了目标精度，误差小于5毫米，但对于极端探头位置，所有变换的累积误差超过了此限制。
该框架是为MATRIX - VT研究开发和测试的，可用于患者数据评估以及在STAR治疗中在超声和CT之间传递诸如移动解剖结构的位置数据等信息进行预测性运动管理。其模块化设计允许纳入先进的校准和配准方法以解决探头定位限制，从而提高未来应用的整体系统性能。
