Necker Fabian N, Melcher Marc L, Busque Stephan, Leuze Christoph W, Ghanouni Pejman, Le Castillo Chris, Nguyen Elizabeth, Daniel Bruce L
Incubator for Medical Mixed Reality at Stanford (IMMERS), Department of Radiology, Stanford University, Palo Alto, CA, USA; Institute of Functional and Clinical Anatomy, Faculty of Medicine, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany; Department of Radiology, Stanford University, Palo Alto, CA, USA.
Stanford Medicine, Department of Surgery - Multi-Organ Transplantation, Stanford University, Palo Alto, CA, USA.
Comput Biol Med. 2024 Dec;183:109267. doi: 10.1016/j.compbiomed.2024.109267. Epub 2024 Oct 12.
Volume-renderings of computed tomography or magnetic resonance angiograms (MRAs) are routinely used by surgeons in the preoperative assessment of vascular anatomy in kidney donors. Stereoscopic headsets (OST-HMD) like Microsoft HoloLens allow intuitive interaction with three-dimensional content for more intuitive comprehension, but do not allow real-time ray-casting volume-rendering of medical volume datasets on-device due to computational limitations.
We introduce NEsted Semi-Transparent Isosurface Simulated Volume-Rendering (NESTIS-VR), as an on-device alternative to ray-casting volume-rendering and developed an application for HoloLens to render kidney donor MRAs with interactive control of fundamental rendering parameters. We compared NESTIS-VR with current standard pre-calculated 2D ray-cast volume-renderings in an observational study with 2 expert kidney transplant surgeons, measuring their confidence in pre-operatively assessing the kidney pedicle arterial anatomy in 20 potential donors. We also compared it against other 3D rendering techniques to understand which features contributed most to any improvements.
Real-time stereoscopic three-dimensional (3D) NESTIS-VR in Augmented Reality significantly improves surgeons' confidence compared with pre-calculated conventional two-dimensional (2D) ray-casting volume-rendered images (p = 0.0415/p = 0.00003). 2D non-stereoscopic NESTIS-VR was significantly superior to pre-calculated 2D ray-casting volume-rendered images for both surgeons (p = 0.044/p = 0.0003). Single isosurface 2D rendering was significantly superior than pre-calculated 2D volume-rendered images for one surgeon. There was no significant difference between binocular 3D display over 2D views with NESTIS-VR or between constrained and unconstrained vantage points for 2D viewing.
NESTIS-VR provides a new approach to rendering medical datasets in computationally limited OST-HMD headsets and significantly increases surgeons' confidence of kidney donor arterial anatomy. The principal confidence benefit arises from providing surgeons interactive control over rendering parameters compared to pre-calculated renderings at preset parameters whilst rendering on-device and keeping the OST-HMD untethered from a workstation.
计算机断层扫描或磁共振血管造影（MRA）的容积再现常用于外科医生对肾脏供体血管解剖结构的术前评估。像微软HoloLens这样的立体头戴式设备（OST-HMD）允许与三维内容进行直观交互，以便更直观地理解，但由于计算限制，无法在设备上对医学容积数据集进行实时光线投射容积再现。
我们引入了嵌套半透明等值面模拟容积再现（NESTIS-VR），作为光线投射容积再现的一种设备端替代方法，并开发了一款适用于HoloLens的应用程序，用于通过对基本渲染参数的交互式控制来渲染肾脏供体的MRA。在一项观察性研究中，我们将NESTIS-VR与当前标准的预先计算的二维光线投射容积再现进行了比较，该研究有2名肾脏移植专家参与，测量了他们在术前评估20名潜在供体肾脏蒂动脉解剖结构时的信心。我们还将其与其他三维渲染技术进行了比较，以了解哪些特征对任何改进贡献最大。
与预先计算的传统二维光线投射容积再现图像相比，增强现实中的实时立体三维（3D）NESTIS-VR显著提高了外科医生的信心（p = 0.0415/p = 0.00003）。对于两位外科医生而言，二维非立体NESTIS-VR均显著优于预先计算的二维光线投射容积再现图像（p = 0.044/p = 0.0003）。对于一位外科医生来说，单一等值面二维渲染显著优于预先计算的二维容积再现图像。在使用NESTIS-VR的双目3D显示与二维视图之间，以及二维视图的受限和非受限视点之间，没有显著差异。
NESTIS-VR为在计算能力有限的OST-HMD头戴式设备中渲染医学数据集提供了一种新方法，并显著提高了外科医生对肾脏供体动脉解剖结构的信心。与在预设参数下预先计算的渲染相比，主要的信心提升来自于为外科医生提供对渲染参数的交互式控制，同时在设备上进行渲染，并使OST-HMD无需连接工作站。
