Assessment of capillary dropout in the superficial retinal capillary plexus by optical coherence tomography angiography in the early stage of diabetic retinopathy

Abstract

BackgroundTo assess capillary dropout in the superficial retinal capillary plexus (SCP) by optical coherence tomography angiography (OCTA) in the early stage of diabetic retinopathy (DR).MethodsThis study was a cross-sectional observational study. Patients that underwent OCTA examinations in our hospital between November 2015 and May 2016 were included in the study. The subjects were divided into two groups: A) normal controls (41 eyes of 41 subjects) and B) the DR patients (49 eyes of 49 patients with mild non-proliferative DR (NPDR)). The retinal thickness and SCP vessel density were analyzed using built-in software in nine sections of the macular area; whole scan area; fovea; parafovea; and sub-sections of the parafovea, superior-hemi, inferior-hemi, temporal, superior, nasal, and inferior. The correlation between vessel density and retinal thickness was also analyzed.ResultsThe SCP density was significantly lower (P < 0.05) in mild NPDR patients than in normal controls in all areas, with the exception of the fovea (P > 0.05). In the parafovea, superior-hemi, inferior-hemi, temporal, and nasal sectors of group B, the SCP density was negatively correlated with the corresponding retinal thickness (P < 0.05). Specifically, as the SCP density decreased, retinal thickness increased.ConclusionsIn the early stage of NPDR, retinal capillary dropout and retinal thickness changes can be clearly captured and analyzed by OCTA. The results confirm a negative correlation between vessel density and retinal thickness in diabetic patients. This noninvasive technique could be applied for DR detection and monitoring. Further study with a larger sample size is warranted.

Association Between Clinical Biomarkers and Optical Coherence Tomography Angiography Parameters in Type 2 Diabetes Mellitus

“…In the early stage of nonproliferative DR, capillary dropout was also identified in the superficial capillary plexus. 9 A decreased vessel density has also been reported in both the superficial and deep capillary plexuses in type 2 diabetes mellitus without DR. 28 In contrast to the 6 × 6-mm 2 scans used in our study, previous studies cited herein have used the central 3 × 3-mm 2 scan for their analysis. Interstudy differences in the retinal segmentation presets among OCT-A imaging systems and the lack of correction for the differences in segmentation boundaries can cause significant errors in OCT-A measurements.…”

“…Most reported a decrease in perifoveal perfusion parameters in the deep retinal layer, 6,7 or in the superficial layer. 8,9 However, Goudot et al 10 found no significant differences, and Rosen et al 11 described greater capillary perfusion in diabetics with no DR compared with controls.…”

Application of optical coherence tomography in clinical diagnosis

“…The high resolution details have been proved to be consistent to those in the anatomic and histological images [29,35,57,58], as an example shown in Figure 4, which makes OCT to be called "optical biopsy". Actually, compared with widely used clinic tomography modalities, the key advantage of OCT is its micrometer resolution which enables the detection of tiny pathological changes and validated the comparable performance of OCT in clinic with some gold diagnosing standards [14,59,60], making OCT a potential clinic alternative in condition of contraindication, tissue removal impossible, avoiding tissue destruction and so on. Take ultrasonic tomography which has similar theory and ability to be used in endoscopy with OCT as example, Mueller-Lisse [61] compared the endoluminal ultrasonography and OCT images of porcine upper urinary tract, and demonstrated the better performance of OCT in distinguishing between urothelium, lamina propria, and muscle layer.…”

“…The vision-affecting-diseases and therapeutic progress change the characters of eye layers [10][11][12][13][14]. The most commonly used markers in ophthalmological OCT diagnosing are retinal thickness, retinal layer structure and choroidal thickness.…”

“…The results showed reduced retinal vascular density and choriocapillar density, and an increase tendency in the choroid vessel density after the dexamethasone implan. Shen [14] compared the superficial vessel distribution of diabetic eyes using a spectral-domain OCTA, and found a lower vessel density while the common OCT showed no obvious difference between the patients and healthy controls.…”