Association of Speckle-Based Blood Flow Measurements and Fluorescein Angiography in Infants with Retinopathy of Prematurity

Abstract

PurposeTo determine the correlation between blood flow metrics measured by intravenous fluorescein angiography (IVFA) and blood flow velocity index (BFVi) obtained by laser speckle contrast imaging (LSCI) in infants with retinopathy of prematurity (ROP). DesignProspective comparative pilot study. SubjectsSeven eyes from seven subjects with ROP. MethodsUnilateral LSCI and IVFA data was obtained from each subject in the neonatal intensive care unit (NICU). Five LSCI-based metrics and five IVFA-based metrics were extracted from images to quantify blood flow patterns in the same region of interest. Correlation between LSCI-based and IVFA-based blood flow metrics was compared between two subgroups of ROP severity: moderate ROP (defined as stage ≤2 without Plus disease) and severe ROP (defined as stage ≥3 or Plus disease). Main Outcome MeasuresPearson and Kendall’s Rank correlation coefficients between IVFA and LSCI metrics; Student’s t test p values comparing LSCI metrics between “severe” and “moderate” ROP groups. ResultsPearson’s correlations between IVFA and LSCI included arterial-venous transit time (AVTT) and peak BFVi (r = -0.917, p = 0.004), AVTT and dip BFVi (r = -0.920, p = 0.003), AVTT and mean BFVi (r = -0.927, p = 0.003), and AVTT and volumetric rise index (r = -0.779, p = 0.039). Kendall’s Rank correlation between AVTT and dBFVi was r = -0.619 (p = 0.051). Peak BFVi was higher in severe ROP than in moderate ROP (8.4 ± 0.6 and 4.4 ± 1.8 respectively, p = 0.0045 using 2-sample t-test with pooled variance, and p = 0.0952 using Wilcoxon rank-sum test). ConclusionCorrelation was found between blood flow metrics obtained by IVFA and noninvasive LSCI techniques. We demonstrate the feasibility of obtaining quantitative metrics using LSCI in infants with ROP in this pilot study, but further investigation is needed to evaluate its potential use in clinical assessment of ROP severity.