Abstract
Purpose :
Pre-term neonates at risk for retinopathy of prematurity (ROP) requires frequent and stressful examination by indirect ophthalmoscopy or RetCam. Plane-wave ultrasound allows visualization and measurement of blood flow through the closed eyelid. In this study we sought to determine the effectiveness of ultrasound Doppler in identifying Stage 3 ROP.
Methods :
Both eyes of 50 preterm neonates (birth weight of ≤1500g or gestational age of ≤30 weeks) were imaged with plane-wave Doppler ultrasound. We acquired 3 scans of each eye with a Verasonics Vantage 128 using an 18 MHz L22-14vXLF linear array probe with 12.8 mm aperture, 18 mm elevation axis focal length. We acquired B-mode data for 1.5 sec at 3,000 images/sec, each image compounded from 6 angled transmits over ±9°. Data were post-processed to produce color-flow images and spectrograms depicting pulsatile flow velocity. Systolic, diastolic and mean velocity and resistance indices in the central retinal artery (CRA), short posterior ciliary artery (SPCA) and central retinal vein (CRV) were determined. ANOVA with post-hoc Dunnett’s test was used to assess the effect of ROP stage on flow parameters. Discriminant analysis was used to evaluate detection of Stage 3 ROP and ROC analysis performed.
Results :
34 eyes were Stage 0 (no ROP), 15 Stage 1, 41 Stage 2 and 10 Stage 3. Birthweight, gestational age and days of life were significantly lower in stage 2 and 3 ROP than non-ROP subjects. There was no difference in blood pressure. Velocities were increased in Stage 3 with respect to controls in the CRA, CRV and SPCA. Resistance indices did not differ significantly by stage but were negatively correlated with post-conception age (R=.23, p<.001). Stepwise linear discriminant analysis selected systolic velocity in the CRV and CRA and resistance in the SPCA, correctly identifying 86% of cases both retrospectively and by cross-validation. The area under the ROC curve was 0.824±.061.
Conclusions :
Plane wave ultrasound allows evaluation of flow in the vessels supplying the eye in a gentle exam. Examination can be carried out through closed eyelids in both eyes in about 10-15 minutes without dilation, lid speculum, bright lights or contact with the eye. Our findings show increased flow velocity in the CRA and CRV and to a lesser extent in the SPCA’s in Stage 3 ROP. There were too few instances of plus disease in this data set to evaluate, but this would be an important focus going forward.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.