IEEE Trans Med Imaging. 2020 Apr;39(4):1015-1029. doi: 10.1109/TMI.2019.2939568. Epub 2019 Sep 5.
Cardiac interventional procedures are often performed under fluoroscopic guidance, exposing both the patient and operators to ionizing radiation. To reduce this risk of radiation exposure, we are exploring the use of photoacoustic imaging paired with robotic visual servoing for cardiac catheter visualization and surgical guidance. A cardiac catheterization procedure was performed on two in vivo swine after inserting an optical fiber into the cardiac catheter to produce photoacoustic signals from the tip of the fiber-catheter pair. A combination of photoacoustic imaging and robotic visual servoing was employed to visualize and maintain constant sight of the catheter tip in order to guide the catheter through the femoral or jugular vein, toward the heart. Fluoroscopy provided initial ground truth estimates for 1D validation of the catheter tip positions, and these estimates were refined using a 3D electromagnetic-based cardiac mapping system as the ground truth. The 1D and 3D root mean square errors ranged 0.25-2.28 mm and 1.24-1.54 mm, respectively. The catheter tip was additionally visualized at three locations within the heart: (1) inside the right atrium, (2) in contact with the right ventricular outflow tract, and (3) inside the right ventricle. Lasered regions of cardiac tissue were resected for histopathological analysis, which revealed no laser-related tissue damage, despite the use of 2.98 mJ per pulse at the fiber tip (379.2 mJ/cm fluence). In addition, there was a 19 dB difference in photoacoustic signal contrast when visualizing the catheter tip pre- and post-endocardial tissue contact, which is promising for contact confirmation during cardiac interventional procedures (e.g., cardiac radiofrequency ablation). These results are additionally promising for the use of photoacoustic imaging to guide cardiac interventions by providing depth information and enhanced visualization of catheter tip locations within blood vessels and within the beating heart.
心脏介入手术通常在荧光透视引导下进行，使患者和操作人员都暴露在电离辐射下。为了降低这种辐射暴露的风险，我们正在探索使用光声成像与机器人视觉伺服控制相结合，以实现心脏导管的可视化和手术引导。在对两只活体猪进行了心脏导管插入术之后，我们将光纤插入心脏导管中，从光纤-导管对的尖端产生光声信号，从而完成了心脏导管插入术。我们使用光声成像和机器人视觉伺服控制的组合来可视化和始终保持对导管尖端的视线，以引导导管穿过股静脉或颈静脉，进入心脏。荧光透视术提供了导管尖端位置的一维验证的初始真实估计值，这些估计值使用基于 3D 电磁的心脏映射系统作为真实值进行了细化。一维和三维均方根误差分别为 0.25-2.28 毫米和 1.24-1.54 毫米。导管尖端还在心脏内的三个位置进行了可视化：（1）在右心房内，（2）与右心室流出道接触，（3）在右心室内部。对心脏组织进行了激光切割区域的组织学分析，尽管在光纤尖端使用了 2.98 mJ 每脉冲（379.2 mJ/cm 剂量），但没有发现与激光相关的组织损伤。此外，在预和后心内膜组织接触时可视化导管尖端时，光声信号对比度有 19 dB 的差异，这对于心脏介入手术中的接触确认很有希望（例如心脏射频消融）。这些结果还为光声成像在心脏介入中的应用提供了希望，因为它可以提供深度信息，并增强血管内和跳动心脏中心导管尖端位置的可视化效果。
