Abstract
Purpose :
To compare two methods of automatic segmentation in the measurement of vascular density (VD) using optical coherence tomography angiography (OCTA) in eyes with macular edema.
Methods :
Thirty-three eyes of 33 retinal vein occlusion (RVO) patients with macular edema were evaluated. All RVO patients with macular edema before and after treatment were imaged using the RTVue XR Avanti(Optvue). OCTA volumes were acquired on the 3 x 3-mm central macular region. Angiograms of the superficial capillary plexus (SCP) and the deep capillary plexus (DCP) were automatically segmented using the latest ReVue software (Version 2017.1.0.131) which can segment 8 lines. The SCP was imaged between internal limiting membrane and 10 μm above the inner plexus layer (IPL). The DCP with latest method was imaged between 10 μm above inner IPL and 10 μm below the outer plexus layer. In contrast, the DCP with previous method was imaged between 15 μm and 70μm below the IPL. We compared each VD with and without macular edema to evaluate the effect of macular edema. The intraclass correlation coefficient (ICC) was calculated to assess the interexaminer reproducibility for each VD.
Results :
1) The VD of the SCP using the latest segmentation method before treatment was significantly correlated with after treatment (p<0.0001) same as the VD of the DCP (p<0.0001). Moreover, the VD of the DCP using the previous method before treatment was also significantly correlated with after treatment (p<0.0001). 2) t-test : Using previous method, the VD in the DCP was significantly increased after treatment (p<0.0001). However, when using the latest method, the VD in the SCP and DCP was not significantly changed before and after treatment (p=0.0135 and p=0.0721, respectively). 3) The interexaminer reproducibility of the VD in the SCP was almost perfect (ICC=0.8642), but the interexaminer reproducibility of the VD in the DCP using latest method and previous method were both moderate (ICC=0.6584 and ICC=0.7762, respectively).
Conclusions :
The vascular density of the DCP is affected by
edema when using the previous segmentation method. The latest version of the segmentation method can provide accurate measurement of retinal vascular density with little or no influence of macular edema.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.