超声增强现实：头戴式显示器在影像引导介入中的混合方法评估。

PURPOSE: Augmented reality (AR) and head-mounted displays (HMD) in medical practice are current research topics. A commonly proposed use case of AR-HMDs is to display data in image-guided interventions. Although technical feasibility has been thoroughly shown, effects of AR-HMDs on interventions are not yet well researched, hampering clinical applicability. Therefore, the goal of this study is to better understand the benefits and limitations of this technology in ultrasound-guided interventions. METHODS: We used an AR-HMD system (based on the first-generation Microsoft Hololens) which overlays live ultrasound images spatially correctly at the location of the ultrasound transducer. We chose ultrasound-guided needle placements as a representative task for image-guided interventions. To examine the effects of the AR-HMD, we used mixed methods and conducted two studies in a lab setting: (1) In a randomized crossover study, we asked participants to place needles into a training model and evaluated task duration and accuracy with the AR-HMD as compared to the standard procedure without visual overlay and (2) in a qualitative study, we analyzed the user experience with AR-HMD using think-aloud protocols during ultrasound examinations and semi-structured interviews after the task. RESULTS: Participants (n = 20) placed needles more accurately (mean error of 7.4 mm vs. 4.9 mm, p = 0.022) but not significantly faster (mean task duration of 74.4 s vs. 66.4 s, p = 0.211) with the AR-HMD. All participants in the qualitative study (n = 6) reported limitations of and unfamiliarity with the AR-HMD, yet all but one also clearly noted benefits and/or that they would like to test the technology in practice. CONCLUSION: We present additional, though still preliminary, evidence that AR-HMDs provide benefits in image-guided procedures. Our data also contribute insights into potential causes underlying the benefits, such as improved spatial perception. Still, more comprehensive studies are needed to ascertain benefits for clinical applications and to clarify mechanisms underlying these benefits.

目的：增强现实（AR）和头戴式显示器（HMD）在医学实践中是当前的研究课题。AR-HMD 的一个常见应用场景是在图像引导介入中显示数据。尽管已经充分证明了其技术可行性，但 AR-HMD 对干预措施的影响尚未得到很好的研究，这阻碍了其临床应用。因此，本研究的目的是更好地了解这项技术在超声引导介入中的优势和局限性。

方法：我们使用了一种 AR-HMD 系统（基于第一代 Microsoft Hololens），该系统可将实时超声图像以正确的空间关系叠加在超声换能器的位置上。我们选择超声引导下的针放置作为图像引导介入的代表性任务。为了研究 AR-HMD 的效果，我们在实验室环境中采用混合方法进行了两项研究：（1）在一项随机交叉研究中，我们要求参与者将针插入培训模型中，并比较使用 AR-HMD 和不使用视觉叠加的标准程序的任务时长和准确性；（2）在一项定性研究中，我们在超声检查过程中使用出声思维协议分析了使用 AR-HMD 的用户体验，并在任务完成后进行了半结构化访谈。

结果：与不使用视觉叠加的标准程序相比，参与者（n=20）使用 AR-HMD 时，针的放置更准确（平均误差为 7.4 毫米 vs. 4.9 毫米，p=0.022），但速度没有明显提高（平均任务时间为 74.4 秒 vs. 66.4 秒，p=0.211）。定性研究中的所有参与者（n=6）都报告了 AR-HMD 的局限性和不熟悉性，但除了一名参与者外，所有人都明确指出了该技术的优势，并且希望在实践中测试该技术。

结论：我们提供了额外的、尽管仍初步的证据，证明 AR-HMD 在图像引导程序中具有优势。我们的数据还为潜在的优势原因提供了见解，例如改善空间感知。不过，仍需要更全面的研究来确定其在临床应用中的优势，并阐明这些优势的潜在机制。