Quantitative evaluation of ocular vascularity and correlation analysis in patients with diabetic retinopathy by SMI and OCTA

Abstract

Abstract Aims To find potential relation between retrobulbar vessels and fundus microvessels and to detect sensitive and effective clinical indicators in predicting the progress of diabetic retinopathy (DR), ocular hemodynamics were measured using superb microvascular imaging (SMI) and ultrawide-field optical coherence tomography angiography (UWF-OCTA). Methods Observational, cross-sectional study evaluating patients with DR with SMI (Aplio i900, Canon Medical) and UWF-OCTA (BM-400K BMizar, Tupai Medical Technology). The peak systolic velocity (PSV), end diastolic velocity (EDV) and resistive index (RI) of central retinal artery (CRA), posterior ciliary artery (PCA) and ophthalmic artery (OA) were measured using SMI. The fundus vascular parameters were evaluated by UWF-OCTA. A correlation analysis was used to determinethe correlation between SMI and UWF-OCTA parameters. Results 139 eyes (29 with no signs of DR (NDR), 36 mild to moderate nonproliferative DR (M-NPDR), 37 severe NPDR (S-NPDR) and 37 PDR) were included. PSV and EDV of retrobulbar vessels decreased from NDR to S-NPDR while increased in PDR. RI of OA showed a decreasing trend in the progression of DR, but other vessels didn’t show the same trend. ROC curve analysis showed that CRAPSV, CRAEDV, PCAEDV, OAPSV and OAEDV had diagnostic value in distinguishing M-NPDR and S-NPDR. From the correlation analysis, a significant association was observed between the SMI parameters of CRA and PCA and UWF-OCTA parameters. CRA hemodynamics were more associated with fundus vascular parameters especially the retina in the NDR group than M-NPDR group. In contrast, PCA consistently correlated with fundus vascular parameters, especially in the choroid, from the NDR to the M-NPDR group. However, OA showed poor correlation with OCTA parameters. Conclusion The velocity of retrobulbar vessels, particularly the CRA may serve as a valuable predictor for assessing the progress of DR. Additionally, SMI may offer substantial significant utility in monitoring disease progression among patients with DR.