Volume Rendering of Angiographic Optical Coherence Tomography Angiography in Fovea Plana and Normal Foveal Pit.

Serena Fragiotta,Alessandro De Paula,Gianluca Scuderi,Andrea Perdicchi,Solmaz Abdolrahimzadeh,Chiara Ciancimino

doi:10.3389/fneur.2021.633492

Serena Fragiotta, Alessandro De Paula + Show 4 more

Open Access

https://doi.org/10.3389/fneur.2021.633492

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Abstract

This paper aims to study adaptative vascular arrangements in idiopathic fovea plana with volume-rendered optical coherence tomography angiography (OCTA). A retrospective review of two cases of idiopathic fovea plana (mean age: 26.5 years) and two age-matched controls imaged with OCTA was conducted using spectral-domain OCTA (RTVue XR Avanti, Optovue, Inc., Fremont, CA) equipped with the AngioVue software. Both en face OCTA slabs and OCTA b scans were processed through Fiji software (http://fiji.sc; software version 2.0.0-rc-68/1.52e), and then extracted as image sequences for volume rendering reconstructions using the ImageVis3D volume rendering system (3.1.0 release). Eyes with idiopathic fovea plana demonstrated a regular superficial vascular plexus connecting to a single vascular monolayer representing the deeper vascular plexuses. At this location, several vertical short path connections were demonstrated, in contraposition with normal eyes where short path connections were infrequently observed. Advances in three-dimensional OCTA reconstruction increase the understanding of vascular connections and arrangement in retinal plexuses and possible anatomical variations that cannot be detected with conventional two-dimensional b scans.

Highlights

Fovea plana is a descriptive term introduced by Marmor et al [1] to characterize the anatomical absence of the foveal pit without functional implications and to introduce a clear distinction with the term foveal hypoplasia which carries a negative functional connotation
Upon optical coherence tomography (OCT) examination foveal hypoplasia was diagnosed as a grade 1 hypoplasia according to the classification of Thomas et al [3] characterized by a very shallow foveal pit and absence of the extrusion of the plexiform layers (Figure 1C)
The introduction of optical coherence tomography angiography (OCTA) improved visualization and understanding of the deeper capillary plexuses, intermediate capillary plexus (ICP) and deep capillary plexus (DCP), which cannot be visualized through conventional fluorescein angiography

Summary

Introduction

Fovea plana is a descriptive term introduced by Marmor et al [1] to characterize the anatomical absence of the foveal pit without functional implications and to introduce a clear distinction with the term foveal hypoplasia which carries a negative functional connotation. Fovea plana has been described as a type of idiopathic foveal hypoplasia that is not linked to congenital abnormalities nor functional defects. It has an incidence that ranges from 1.7 to 3% in Microvascular Changes in Fovea Plana normal children [2] and is described as a bilateral condition, more commonly presenting as grade 1 or grade 2 foveal hypoplasia according to Thomas et al [3] classification by which the lower grades correspond to a better visual prognosis. It can be diagnosed thanks to optical coherence tomography (OCT) scans, where the absence of the foveal pit, or the presence of a very shallow pit, are visualized readily

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