Autonomous Diagnostic Imaging Performed by Untrained Operators Using Augmented Reality as a Form of

Introduction
Imaging technologies are key to the diagnosis and treatment of medical conditions that astronauts on an exploration mission might encounter and to research activities that characterize and understand the adaptations to micro- and partial gravity environments. Key limitations of the currently available imaging capabilities include the complexity and operator dependency of the procedures to acquire high quality results. Currently, two imaging procedures critical to space medicine and research, ultrasound and optical coherence tomography (OCT), are performed on the International Space Station (ISS) by astronauts with the assistance of real-time communication with experts on the ground using a method called remote guidance. With this methodology astronauts have acquired diagnostic and research quality data that are central to our understanding of the physiological consequences of weightlessness, including altered cardiac function, muscle atrophy, and the spaceflight-associated neuro-ocular syndrome (SANS). However, with the time delay in communications that will be inherent in exploration missions while traveling great distances from Earth, remote guidance will no longer be practical, particularly when one-way transmissions may take up to 10 minutes or more. To fill this gap, we developed advanced audio-visual training modules, a form of just-in-time (JIT) training, to acquire medically necessary and research-relevant images. Building on our extensive experience with remote guidance of ISS astronauts and demonstrated success with just-in-time training, we employed an augmented reality (AR) system (Microsoft HoloLens) that included three-dimensional graphics of relevant anatomy, step-by-step audio instruction, reference images demonstrating adequate and inadequate quality, and troubleshooting guides. The ability of untrained subject-operators to acquire high-quality ultrasound and OCT images was evaluated by expert reviewers and compared to current JIT techniques for quality and time efficiency.
Methods
Tutorials to acquire ultrasound and OCT images were adapted for use as a PowerPoint presentation viewed either on a laptop computer or using an augmented reality platform with a heads-up display. Instructional material presented by the two different training modalities was identical, except that the augmented reality tutorial provided additional spatial guidance to complete the scanning protocols. Additional guidance included arrows superimposed on the ultrasound and OCT keyboards when specific controls were needed and virtual green dots superimposed on the body over the ultrasound targets' approximate locations to guide ultrasound probe placement. Twenty subjects attempted to acquire ultrasound and OCT images using the tutorials provided viewed on a laptop computer, and 20 subjects attempted the same diagnostic imaging procedures with instructions viewed using the AR system. No subject had prior experience performing these procedures or using this imaging hardware, and no subject participated in this study as a member of both groups. Subjects used guidance from the tutorials to acquire five ultrasound targets that constitute a subset of images in a trauma-induced injury assessment protocol (images of the heart, lungs, liver, kidney and spleen) and a single thirteen-line, vertical raster scan centered on the macula of the left eye using OCT. Time limits were imposed upon the subjects to acquire each of the ultrasound or OCT targets. This is not dissimilar to the environment on ISS or anticipated on future exploration missions in which communication windows or mission objectives can impact the available time to complete imaging procedures.
After the data collection session, subjects completed a survey to capture their thought about the equipment, procedures, instructional material, and future improvements. Images were stored by the subjects and evaluated off-line in a blind