Jackson Peter, Merrell Kelly, Simon Richard, Linte Cristian
Center for Imaging Science.
Department of Biomedical Engineering, Rochester Institute of Technology Rochester, NY 14623, USA.
Proc SPIE Int Soc Opt Eng. 2022 Feb-Mar;12034. doi: 10.1117/12.2613457. Epub 2022 Apr 4.
Minimally invasive image-guided interventions (IGIs) enable better therapy outcomes for patients, but navigation accuracy is highly dependent on the accuracy of the image-/model-to-patient registration. This requires methods to reduce the uncertainty to a level appropriate for the procedure being performed. Since sub-surface tissue landmarks cannot be easily sampled using a tracked stylus and used to perform the patient registration, here we present a method that employs a tracked camera (that mimics a laparoscope) to perform the patient registration or update this registration in case of suspected misalignment within the context of an image-guided renal navigation procedure. We implement and test the method using a simplified patient phantom, which consists of a foam block to which a virtual kidney model featuring both surface and sub-surface landmarks is registered. This setup mimics a situation when a surgeon would navigate a tracked needle to renal landmarks percutaneously, while relying on pre-procedural imaging, optical tracking, and surface video imaging. We conduct several experiments under both optimal phantom registration and purposely altered registration, to not only show the effect of phantom / patient mis-registration on subsequent navigation, but also demonstrate the use of the camera-based registration to restore navigation to an acceptable uncertainty. Our results illustrate that camera-based registration yields a target registration error on the order of 0.4 mm and a subsequent targeting error on the order of 0.6 mm, comparable to the performance achieved following gold-standard landmark-based registration. These results suggest that the proposed method can be used to perform or update the patient registration for image-guided interventions involving sub-surface organs.
微创图像引导介入治疗（IGIs）能为患者带来更好的治疗效果，但导航精度高度依赖于图像/模型与患者配准的准确性。这就需要采用一些方法将不确定性降低到适合所执行手术的水平。由于使用跟踪探针难以轻松采集皮下组织标志物并用于患者配准，因此我们在此提出一种方法，该方法采用跟踪摄像头（模拟腹腔镜）进行患者配准，或者在图像引导肾导航手术过程中怀疑出现配准错误时更新配准。我们使用简化的患者模型来实现和测试该方法，该模型由一个泡沫块组成，一个具有表面和皮下标志物的虚拟肾脏模型已配准到该泡沫块上。这种设置模拟了外科医生在依赖术前成像、光学跟踪和表面视频成像的情况下，经皮将跟踪针导航至肾脏标志物的情况。我们在最佳模型配准和故意改变配准的情况下进行了多项实验，不仅展示了模型/患者配准错误对后续导航的影响，还证明了基于摄像头的配准可将导航恢复到可接受的不确定性水平。我们的结果表明，基于摄像头的配准产生的目标配准误差约为0.4毫米，随后的靶向误差约为0.6毫米，与基于金标准标志物配准所取得的性能相当。这些结果表明，所提出的方法可用于执行或更新涉及皮下器官的图像引导介入治疗的患者配准。
