PURPOSE For laparoscopic ablation to be successful, accurate placement of the needle to the tumor is essential. Laparoscopic ultrasound is an essential tool to guide needle placement, but the ultrasound image is generally presented separately from the laparoscopic image. We aim to evaluate an augmented reality (AR) system which combines laparoscopic ultrasound image, laparoscope video, and the needle trajectory in a unified view. METHODS We created a tissue phantom made of gelatin. Artificial tumors represented by plastic spheres were secured in the gelatin at various depths. The top point of the sphere surface was our target, and its 3D coordinates were known. The participants were invited to perform needle placement with and without AR guidance. Once the participant reported that the needle tip had reached the target, the needle tip location was recorded and compared to the ground truth location of the target, and the difference was the target localization error (TLE). The time of the needle placement was also recorded. We further tested the technical feasibility of the AR system in vivo on a 40-kg swine. RESULTS The AR guidance system was evaluated by two experienced surgeons and two surgical fellows. The users performed needle placement on a total of 26 targets, 13 with AR and 13 without (i.e., the conventional approach). The average TLE for the conventional and the AR approaches was 14.9 mm and 11.1 mm, respectively. The average needle placement time needed for the conventional and AR approaches was 59.4 s and 22.9 s, respectively. For the animal study, ultrasound image and needle trajectory were successfully fused with the laparoscopic video in real time and presented on a single screen for the surgeons. CONCLUSION By providing projected needle trajectory, we believe our AR system can assist the surgeon with more efficient and precise needle placement.

中文翻译：

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腹腔镜肝消融的超声增强针导航的临床前评估。

目的为了成功地进行腹腔镜消融，将针头准确地放置在肿瘤上至关重要。腹腔镜超声是引导针头放置的必不可少的工具，但是超声图像通常与腹腔镜图像分开显示。我们旨在评估一种增强现实（AR）系统，该系统在统一视图中结合了腹腔镜超声图像，腹腔镜视频和针头轨迹。方法我们创建了一个由明胶制成的组织模型。以塑料球为代表的人工肿瘤被固定在明胶中的各个深度处。球体表面的最高点是我们的目标，并且3D坐标是已知的。邀请参与者在有和没有AR指导的情况下进行针头放置。一旦参与者报告针尖已经达到目标，记录针尖位置并将其与目标的地面真实位置进行比较，不同之处在于目标定位误差（TLE）。还记录了针放置的时间。我们进一步在40公斤猪身上测试了AR系统在体内的技术可行性。结果由两名经验丰富的外科医生和两名外科医师对AR指导系统进行了评估。用户在总共26个目标上进行了针头放置，其中13个带有AR，13个没有AR（即常规方法）。传统方法和AR方法的平均TLE分别为14.9 mm和11.1 mm。传统方法和AR方法所需的平均针头放置时间分别为59.4 s和22.9 s。对于动物研究，超声图像和针头轨迹已成功地与腹腔镜视频实时融合，并在单个屏幕上呈现给外科医生。结论通过提供预期的针头轨迹，我们相信我们的AR系统可以协助外科医生更有效，更准确地放置针头。