Hand held OCT probe optimized for supine optical coherence tomography angiography

Abstract

Purpose : We have previously reported on a custom, ultra-light, hand held swept source probe for routine bedside imaging of infants in the intensive care nursery (ICN). This work describes the development of a new, novel, hand held probe with a larger field of view that is capable of hand held optical coherence tomography angiography (HH-OCTA) in supine subjects. HH-OCTA will allow for OCTA imaging of traditionally non-compliant patients such as infants in the ICN.

Methods : A custom hand held probe was developed using a novel design incorporating diverging light on the scanner to accomplish diffraction limited performance over a 9.5x9.5 mm field of view on the retina. This system uses a 200 kHz 1060 nm swept source OCT engine, has 101 dB peak sensitivity, and 12 micron axial resolution. Under a protocol approved by the Duke Institutional review board, OCT volumes and OCTA images were acquired on an undilated, healthy adult volunteer in a supine position. OCT volumes were taken over an approximately 10x10 field of view with 1000 A-scans/B-scan and 128 B-scans/volume. OCTA images were taken of the central macula and peripapillary area over approximately 3x3 mm and 1.5x1.5 mm fields of view respectively. OCTA images were acquired with 300 A-scans/B-scan, 300 B-scans/volume, with 4 repeat scans at each B-scan location. OCTA images were generated in post processing using speckle variance and graph cut based segmentation was used to create projections of the vasculature.

Results : The custom probe, B-scans, and OCTA images of the central macula and peripapillary area of a healthy volunteer are shown in figure 1. HH-OCTA of the central macula shows fine perifoveal capillaries defining the foveal avascular zone. HH-OCTA of the peripapillary area shows larger retinal vessels as well as the peripapillary capillary network emerging radially from the optic nerve head.

Conclusions : We have demonstrated HH-OCTA in a healthy normal adult in a supine position. HH-OCTA was able to show fine vascular features and it will allow for OCTA imaging of traditionally non-compliant patients.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.

 

Figure 1: Top: B-scan excerpts from the same volume showing the central macula (left) and peripapillary area (right) of a healthy adult volunteer. Bottom: Custom hand held probe (left), HH-OCTA from the central macula (middle), and HH-OCTA of the superficial vasculature in the peripapillary area (right).