Role of Optical Coherence Tomography Angiography to differentiate Intraretinal microvascular abnormalities and retinal neovascularization in Diabetic Retinopathy.

Nasir Ahmed Memon,Pir Salim Mahar,Abdul Sami Memon

doi:10.12669/pjms.38.1.3891

Abstract

ABSTRACTObjective:To assess proliferative diabetic retinopathy (PDR) and to describe the difference in angiographic representation of new vessels (NVs) and Intra retinal microvascular abnormalities (IRMA) on optical coherence tomography angiography (OCTA).Methods:A cross-sectional observational study was performed at ISRA Postgraduate Institute of Ophthalmology, Karachi, from March 2018 to September 2018. Forty-two eyes of 21 patients with history of diabetes mellitus (DM) were examined. Twenty-eight eyes with a clinical diagnosis of severe non proliferative diabetic retinopathy (NPDR) or proliferative diabetic retinopathy (PDR) according to early treatment diabetic retinopathy study (ETDRS) were included and evaluated using Swept source optical coherence tomography angiography (SS-OCTA). Then face wide field SS-OCTA images and co registered structural optical coherence tomography (OCT) with flow overlay were used to distinguish the features of IRMA and retinal NVs.Results:Forty-two eyes (21 patients) were examined clinically. Fourteen eyes had moderate NPDR, 15 had severe NPDR and 13 eyes had changes consistent with PDR. After clinical diagnosis, we included 28 eyes in our study based on inclusion criteria. These 28 eyes went through SS-OCTA evaluation and we observed 15 cases with PDR and 13 with severe NPDR changes. The OCTA and clinical diagnosis were similar except in 2 eyes, which is critical but not statically significant showing the importance of this noninvasive technology.Conclusions:Widefield OCTA can work as an alternative to fundus fluorescein angiography (FFA) in the diagnosis of diabetic retinopathy (DR). As it is a non-invasive and depth encoded technique so can be used frequently to monitor the retinal changes and their progression.

Highlights

Diabetic retinopathy (DR) is one of the leading complications of diabetes mellitus (DM) with the treatment philosophy based on the severity of the retinal changes
The non-proliferative diabetic retinopathy (NPDR) manifests microvascular changes, including micro aneurysms, intra retinal hemorrhages, venous beading and intra retinal microvascular abnormalities (IRMA), whereas proliferative diabetic retinopathy (PDR) is identified by retinal neovascularization (NV) that develops in response to retinal ischemia
new vessels (NVs) are bunch of fine vessels lying on the surface of the retina, while Intra retinal microvascular abnormalities (IRMA) are defined as collateral vessels arising from the preexisting capillaries and are located entirely within the retina and are difficult to distinguish from early extra retinal neovascularization

Summary

Introduction

Diabetic retinopathy (DR) is one of the leading complications of diabetes mellitus (DM) with the treatment philosophy based on the severity of the retinal changes. Detection of severe NPDR and early PDR is very important in DR treatment as the chance of progression to vision threatening diabetic retinopathy (VTDR) within one year is calculated at 50 percent.[3] Optical coherence tomography (OCT) is a non-invasive technique and has gained popularity over the last two decades for acquiring cross sectional retinal images. It is based on the principle of optical reflectometry, which involves the measurement of light back-scattering through transparent or semi-transparent media such as retina.[4] It is useful for the diagnosis and monitoring of DR, especially diabetic macular edema (DME). Face OCTA can visualize the vascular structure of retina and choroid and is ideal noninvasive tool for diagnosis, management and monitoring of different stages of DR, Age related macular degeneration (ARMD) and other chorioretinal vascular disorders.[7,8]

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