Laser Speckle Imaging for Retinopathy of Prematurity: A Pilot Study

Abstract

Purpose : Growing evidence suggests an association between laser speckle-based blood flow dynamics and retinopathy of prematurity (ROP) severity and response to treatment. Given the promising clinical utility of this technology, our team initiated a pilot study for laser speckle imaging (LSI) in infants at risk for retinopathy of prematurity to refine methods and procedures for the neonatal intensive care unit (NICU) setting. Pilot study results include the operator learning curve, rate of successful imaging acquisition over time, and the precision and repeatability of LSI data.

Methods : Subjects were premature infants (n=50, gestational age 27+/-3 weeks, birthweight 960+/-440 grams). 518 images over 20 months included a subset of repeat images in a single session, and in separate same-day sessions. Bivariate analyses included image acquisition speed and image quality by study month. Multivariable logistic regression was used to determine if the age of subject or number of imaging sessions was associated with the duration of imaging or the quality of images. Four LSI regions were analyzed after registration for repeatability: full field of view, vessels in the optic disc, and two significant vessels not in the optic disc. Intra-session coefficient of variation (CV) was computed across multiple cardiac cycles in 15 datasets gathered from 6 subjects in one session. Inter-session CV was computed by first averaging all measurements from multiple cardiac cycles within each session, and then computing CV across at least two sessions among 6 different subjects. Measurements were heart-rate adjusted.

Results : Speed of image acquisition was 1.6 +/- 1.2 minutes/image. Total exam duration was 5.1+/- 3.8 minutes per eye. Each month of the pilot study, we increased our speed of image acquisition by 6 seconds on average. The proportion of high-quality images increased from 40% to 70% and continue to show an upward trend of improvement in image quality. Age of the subject and number of imaging sessions did not influence the speed or quality of image acquisition (p=0.69, p=0.59). Operator experience correlated with speed (p<0.001) and quality (p=0.02). Intra-session CV ranged from 2.7-5.1%. Inter-session CV ranged from 9.9-29.9%.

Conclusions : LSI in the NICU setting can be executed with a high proportion of excellent quality images, quick acquisition speed, and high repeatability.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.