Validation of a Low-cost Optic Nerve Sheath Ultrasound Phantom: An Educational Tool

Abstract

Objective: To validate an ocular phantom as a realistic educational tool utilizing in vivo and phantom optic nerve sheath (ONS) images obtained by ultrasound. Methods: This prospective study enrolled 51 resident physicians from the Denver Health Residency in Emergency Medicine (EM) and 10 ultrasound fellowship-trained EM attending physicians. Participants performed optic nerve sheath diameter (ONSD) measurements on five in vivo and five phantom ocular ultrasound images and rated the realism of each image on a 5-point Likert scale. Chi-square analysis was performed to evaluate the subjective “realness” of in vivo and phantom images. Results: Sixty-one participants performed ONSD measurements. Mean Likert scale values were 3.43 (95% confidence interval: 3.31–3.55) for in vivo images and 3.41 (95% confidence interval: 3.28–3.54) for phantom images. There was no statistical difference in subjective “realness” between in vivo and phantom ONSD ultrasound images among EM residents. Ultrasound fellowship-trained EM attending physicians aptly differentiated between in vivo (p<0.01) and phantom (p<0.01) images, as compared with EM residents. Conclusion: Our ocular phantom simulates in vivo posterior ocular anatomy. EM resident physicians found the phantom indistinguishable from in vivo images. Our ONS model provides an inexpensive and realistic educational tool to teach bedside ONSD sonography.

Keywords

• emergency medicine
• ocular ultrasound
• optic nerve sheath diameter
• ultrasound phantom