Head orientation-independent optical coherence tomography with a robotically-aligned scanner

Abstract

Purpose : Standard-of-care optical coherence tomography (OCT) systems are manually-aligned tabletop instruments that require strict patient cooperation and careful head stabilization with chinrests. These requirements limit imaging of pediatric patients, who are frequently unwilling or unable to cooperate, and of bedbound or hospitalized patients, who cannot use a tabletop OCT system. Compensation for variation in both position and orientation of the patient’s head is necessary for successful imaging under such circumstances.

Methods : We extend our previous robotically-aligned OCT (RAOCT) scanner to support face tracking without assumptions on head orientation (Fig. 1). Two scanner-integrated depth cameras replaced previous fixed-mount cameras, and we generated an artificial frontal face view for subject tracking from their composite face surface maps. Our control software then maneuvered the robot to position the scanner’s pupil pivot at the subject’s pupil and to match the subject’s head orientation. We evaluated this approach through IRB-approved imaging of human subjects in varied head orientations. Subjects were either freestanding or seated upright facing the system and were asked to orient their head with non-zero pitch and yaw. An operator then triggered the system to perform semi-automatic alignment and imaging of the desired eye, after which the system returned to its starting configuration. We conducted imaging in this fashion for multiple positions and head orientations for each subject.

Results : The RAOCT system successfully obtained motion-stabilized OCT images in widely varying subject positions and head orientations (Fig. 2a). For each subject, OCT volumes obtained with different positions and orientations captured the target retinal anatomy (Fig. 2b). The time to first images after initiation of alignment was routinely under 30 seconds.

Conclusions : Robotically-aligned OCT with scanner-integrated head tracking enables reliable imaging of subjects with arbitrary head orientations. This approach promises to facilitate imaging of pediatric and hospitalized patients.

This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.

 

Robotically-aligned OCT scanner with integrated face tracking cameras (left) aligned with an elevated head orientation (right).

 

Representative retinal B-scans for one subject with the head tilted up (left) and the head turned right (right) both by approximately 30 degrees, demonstrating imaging across diverse head orientations.