The role of standardized A-scan echography in improving the accuracy of ultrasound diagnosis of vitreoretinal pathology

Background

Ultrasound remains one of the primary diagnostic methods for vitreoretinal pathology, particularly in eyes with opaque optical media. However, the differential diagnosis of retinal detachment, retinoschisis, posterior vitreous detachment, and vitreous strands is often challenging because of their similar echographic appearance. Therefore, the search for additional quantitative criteria for the assessment of intraocular structures remains an important objective of contemporary ophthalmic echography.

Aim

To evaluate the capabilities of standardized A-scan ultrasonography in the differential diagnosis of retinal detachment, posterior vitreous detachment, retinoschisis, and vitreous strands, and to determine the most informative quantitative acoustic criteria for these pathological conditions.

Methods

A total of 210 patients (210 eyes) with vitreoretinal pathology aged 18 to 71 years (mean age 52.4 ± 11.8 years) were examined. The study included 80 patients (80 eyes) with retinal detachment, 76 patients (76 eyes) with posterior vitreous detachment, 34 patients (34 eyes) with vitreous strands, and 20 patients (20 eyes) with retinoschisis. All patients underwent comprehensive ophthalmic ultrasound including B-scan and standardized A-scan echography using the Retina A1 and Retina QII modes. Signal amplitude, the number of internal signal oscillations, and tissue reflectivity relative to the scleral reference signal were evaluated.

Results

According to B-scan ultrasound, retinal detachment was identified in 76 of 80 patients (95.0%), posterior vitreous detachment in 71 of 76 patients (93.4%), vitreous strands in 31 of 34 patients (91.2%), and retinoschisis in 18 of 20 patients (90.0%). Interpretation of ultrasound findings was challenging in 28 patients (13.3%) because of similar echographic characteristics of the detected pathological structures. Standardized A-scan echography demonstrated Retina A1 values corresponding to “R++” and “R+++” in patients with retinal detachment, while the mean tissue reflectivity difference relative to the sclera was 11.2 ± 2.9 dB. In posterior vitreous detachment, Retina A1 values corresponded to “M+” and “M++,” with a mean reflectivity difference of 18.6 ± 4.3 dB. In vitreous strands, Retina A1 values corresponded to “M++” and “M+++,” and the mean reflectivity difference was 24.8 ± 5.1 dB. In retinoschisis, Retina A1 values corresponded to “R++” and “R+++” in 15 patients (75.0%) and to “M++” in 5 patients (25.0%); the mean reflectivity difference was 20.9±5.8 dB. No statistically significant differences were found between the reflectivity values of retinal detachment and retinoschisis, or between posterior vitreous detachment and vitreous strands (p 0.05). However, significant differences were observed between retinal and vitreous structures (p 0.05).

Conclusion

Standardized A-scan echography combined with conventional B-scan ultrasound improves the diagnostic accuracy of vitreoretinal pathology. The method is particularly useful for differentiating retinal from vitreous pathological structures.