In vivo rotational three-dimensional OCTA analysis of microaneurysms in the human diabetic retina

Enrico Borrelli,Giuseppe Querques,Maria Brambati,Francesco Bandello,Riccardo Sacconi

doi:10.1038/s41598-019-53357-1

Enrico Borrelli, Giuseppe Querques + Show 3 more

Open Access

https://doi.org/10.1038/s41598-019-53357-1

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Journal: Scientific Reports	Publication Date: Nov 14, 2019
Citations: 41	License type: open-access

Affiliation: IRCCS Ospedale San Raffaele

Abstract

The aim of this study was to explore whether rotational three-dimensional (3D) visualization of optical coherence tomography angiography (OCTA) volume data may yield valuable information regarding diabetic retinal microaneurysm (MA) characteristics. In this retrospective, observational study, we collected data from 20 patients (20 eyes) with diabetic retinopathy. Subjects were imaged with the SS-OCTA system (PLEX Elite 9000, Carl Zeiss Meditec Inc., Dublin, CA, USA). The OCTA volume data were processed with a volume projection removal algorithm and then exported to imageJ in order to obtain a 3D visualization of the analyzed MAs. The rotational three-dimensional OCTA images were qualitatively and quantitatively investigated. A total of 52 MAs were included in the analysis. On rotational 3D OCTA images, the number of vessels associated with each MA varied between 1 and 4, and most MAs (59.6%) were associated with 2 vessels. Moreover, in 20 MAs (38.4%) these vessels seem to originate from the SCP, while 26 MAs (50.0%) had associated vessels originating from the DVC, and 6 MAs had associated vessels arising from both the SCP and DVC (11.6%). Most MAs (31/52) had a ‘saccular’ shape. The number of retinal layers occupied by each MA ranged between 1 and 3 and the inner nuclear layer was the retinal layer most frequently occupied by MAs. In conclusion, this study used an algorithm to obtain rotational three-dimensional visualization of retinal MAs. The MAs’ architecture is complex and 3D visualization may clarify the true vascular origin of these lesions, which is often mistaken using en face OCTA images.

Highlights

Microaneurysms (MAs) are dilations of capillaries that usually appear as gross outpouchings of the vessel wall
Using Optical coherence tomography angiography (OCTA), the retinal vasculature may be visualized at different depths in order to display and assess three distinct retinal capillary layers: vessels located in the retinal nerve fiber and ganglion cell layers constitute the superficial retinal capillary plexus (SCP), while the middle capillary plexus and the deep retinal capillary plexus (DCP) are located at the inner and outer borders of the inner nuclear layer, respectively[7,8]
A total of 63 microaneurysms were identified on the 2D OCTA images (22/63 [34.9%] on the SCP en face image and 41/63 [65.1%] on the deep vascular complex (DVC) en face image, respectively)

Summary

Introduction

Microaneurysms (MAs) are dilations of capillaries that usually appear as gross outpouchings of the vessel wall. The flow data within any slab are summed or projected into a two-dimensional en face image[5] This two-dimensional (2D) visualization may offer limited knowledge of the relative frequency of the various types of microaneurysms and their origin, location and orientation within the retina. These shortcomings may be partially addressed with the development of three-dimensional (3D) illustrations, assuming that the acquired OCTA volume enables 3D visualization of the retinal and choroidal microvasculature. These 3D visualizations may be rotated on the 3 axes and this may further reduce limitations by overlapping anatomy and vessel foreshortening, as demonstrated for other imaging modalities (e.g. cerebral angiograms)[17]

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