Marcel Bernucci: Investigation of vascular scattering patterns in retinal and choroidal OCT angiography with a contrast agent

Optical Coherence Tomography Angiography (OCTA) has recently emerged for imaging vasculature in clinical ophthalmology. Yet, apparent OCTA image artifacts, often caused by the high scattering property of red blood cells (RBCs), can be challenging to interpret.

In his presentation, "Investigation of vascular scattering patterns in retinal and choroidal OCT angiography with a contrast agent," Marcel Bernucci, junior specialist in the biomedical engineering lab at University of California, Davis, discusses how his research uses contrast-enhanced OCTA in rats to help explain these apparent artifacts.



"In order to better interpret OCTA, it's important that the origins of any artifacts that may arise when performing such a technique be understood," says Bernucci.

He notes that, "current explanations for OCTA image artifacts in the literature are based on either in vitro experiments or clinical correlations. Thus, a controlled in vivo demonstration of the biophysical origins of OCTA artifacts is needed."



By quantifying enhancement due to an intravascular contrast agent with rheological and scattering properties that are different from red blood cells (RBCs), OCTA image features are ascribed to specific rheological and scattering properties of RBCs. By imaging pigmented and unpigmented rats at a wavelength where scattering dominates image contrast (1300 nm), the impact of melanosome scattering on OCT and OCTA signals can be determined.

Bernucci's research shows the impact of RBC orientation on intravascular scattering patterns and vessel detectability; the role of RBC forward scattering in projection artifacts; and the influence of melanosomes on the OCTA signal from the choroid and sclera.

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