Clinical Implications of Suspended Scattering Particles in Motion Observed by Optical Coherence Tomography Angiography

Jaemoon Ahn,Seong-Woo Kim,Sangheon Han,So Min Ahn,Jaeryung Oh

doi:10.1038/s41598-019-55606-9

Abstract

The objective of this study was to investigate the relationship between suspended scattering particles in motion (SSPiM) in optical coherence tomography angiography (OCTA) and treatment response in diabetic macular edema (DME). We retrospectively reviewed the medical records of patients diagnosed with DME who had undergone intravitreal injection. The optical density ratio (ODR) of the intraretinal cyst and the numbers of hyperreflective foci from OCT images and SSPiM from OCTA images were compared, and their association with treatment response was analyzed. Forty-five eyes from 45 patients were included in this study. Twenty-four patients were treated with anti-vascular endothelial growth factor, and 21 patients were treated with a steroid. Binary logistic regression model showed that SSPiM in OCTA images was associated with hyperreflective foci numbers (P = 0.038) and mean ODR of the intraretinal cyst (P = 0.006). Linear regression model showed that SSPiM in the inner nuclear layer was related to treatment response (P = 0.006). SSPiM on OCTA images is related to the poor structural response to treatment in DME.

Highlights

Because optical coherence tomography angiography (OCTA) does not use dye, it is comparatively simple and does not selectively mark blood vessels, unlike other angiography techniques
The purpose of the current study is to investigate the relationship between suspended scattering particles in motion (SSPiM) and treatment response in Diabetic macular edema (DME)
Differences According to the Presence or Absence of SSPiM in OCTA Images

Summary

Introduction

Because OCTA does not use dye, it is comparatively simple and does not selectively mark blood vessels, unlike other angiography techniques. There is the possibility of various artifacts in OCTA images, as have been reported in previous studies[10,11,12,13]. Kashani et al recently reported a novel artifact-like feature called suspended scattering particles in motion (SSPiM)[14]. This likely represents actual flow of suspended particles in intraretinal fluid, not an artifact. The authors suggested that more severe blood-retinal barrier (BRB) breakdown resulted in greater particle outflow, leading to SSPiM. We suspect that a difference in BRB breakdown will affect treatment response and be of clinical relevance. Breakdown of the inner BRB increases serum exudation from the retinal vessel.

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Conclusion