Purpose

Intraoperative optical coherence tomography (iOCT) was recently introduced as a new modality for ophthalmic surgeries. It provides real-time cross-sectional information at a very high resolution. However, properly positioning the scan location during surgery is cumbersome and time-consuming, as a surgeon needs both his hands for surgery. The goal of the present study is to present a method to automatically position an iOCT scan on an anatomy of interest in the context of anterior segment surgeries.

Methods

First, a voice recognition algorithm using a context-free grammar is used to obtain the desired pose from the surgeon. Then, the limbus circle is detected in the microscope image and the iOCT scan is placed accordingly in the X–Y plane. Next, an iOCT sweep in Z direction is conducted and the scan is placed to centre the topmost structure. Finally, the position is fine-tuned using semantic segmentation and a rule-based system.

Results

The logic to position the scan location on various anatomies was evaluated on ex vivo porcine eyes (10 eyes for corneal apex and 7 eyes for cornea, sclera and iris). The mean euclidean distances (± standard deviation) was 76.7 (± 59.2) pixels and 0.298 (± 0.229) mm. The mean execution time (± standard deviation) in seconds for the four anatomies was 15 (± 1.2). The scans have a size of 1024 by 1024 pixels. The method was implemented on a Carl Zeiss OPMI LUMERA 700 with RESCAN 700.

Conclusion

The present study introduces a method to fully automatically position an iOCT scanner. Providing the possibility of changing the OCT scan location via voice commands removes the burden of manual device manipulation from surgeons. This in turn allows them to keep their focus on the surgical task at hand and therefore increase the acceptance of iOCT in the operating room.

中文翻译：

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术中自动光学相干断层扫描定位。

目的

术中光学相干断层扫描（iOCT）最近被引入作为眼科手术的新形式。它以高分辨率提供实时横截面信息。但是，在手术过程中正确定位扫描位置既麻烦又费时，因为外科医生需要双手进行手术。本研究的目的是提出一种在前节段手术中自动将iOCT扫描定位在感兴趣的解剖结构上的方法。

方法

首先，使用无上下文语法的语音识别算法用于从外科医生获得所需姿势。然后，在显微镜图像中检测到角膜缘圆，并将iOCT扫描相应地放置在X – Y平面中。接下来，在Z方向进行iOCT扫描，并放置扫描以使最上面的结构居中。最后，使用语义分割和基于规则的系统对位置进行微调。

结果

在离体猪眼中评估扫描位置在各种解剖结构上的逻辑（10只眼用于角膜顶点，7只眼用于角膜，巩膜和虹膜）。欧氏平均距离（±标准偏差）为76.7（±59.2）像素和0.298（±0.229）mm。四个解剖结构的平均执行时间（±标准偏差）以秒为单位为15（±1.2）。扫描的大小为1024 x 1024像素。该方法在带有RESCAN 700的Carl Zeiss OPMI LUMERA 700上实现。

结论

本研究介绍了一种完全自动定位iOCT扫描仪的方法。通过语音命令提供更改OCT扫描位置的可能性，消除了外科医生手动操作设备的负担。反过来，这使他们可以将精力集中在手头的外科手术上，从而提高了iOCT在手术室中的接受度。