Luminal and Stromal Areas of Choroid Determined by Binarization Method of Optical Coherence Tomographic Images

Comparison of Choroidal Vascularity Markers on Optical Coherence Tomography Using Two-Image Binarization Techniques

“…All statistical analyses were performed using statistical software (SPSS version 20.0; IBM Corp. Armonk, NY, USA) and statistical significance was evaluated at 5% level. 19 (C, F, I) OCT images after binarization using technique proposed by Sonoda et al 18 (A-C) One subject in which choroidal vascularity index (CVI) is similar to luminal/ choroidal ratio (L/C ratio). (D-F) One subject in which CVI is smaller than L/C ratio.…”

“…Binarization was performed separately using techniques proposed by Sonoda et al 18 and Agrawal et al 19 Detailed algorithms for both techniques were described previously. Both techniques were carried out with ImageJ (version 1.47; provided in the public domain by the National Institutes of Health, Bethesda, MD, USA; https://imagej.nih.…”

“…18,19 This has led to the creation of a novel structural marker for choroidal vascularity, which is the ratio of vascular (or luminal) area to total choroidal area. It was termed ''choroidal vascularity index (CVI)'' by Agrawal et al 19 or ''luminal/choroidal area ratio (L/C ratio)'' by Sonoda et al 18 This new marker of choroidal vascularity has been investigated in normal physiologic conditions 18,[20][21][22][23] and also validated as a useful tool in various ocular diseases. 19,[24][25][26][27][28][29][30][31][32][33][34][35][36] Differences exist in the image binarization algorithms for the calculation of CVI and L/C ratio.…”

“…In the technique proposed by Sonoda et al, 18 choroidal segmentation was performed before binarization by manual plotting of the total choroidal area (TCA) extending from RPE/ Bruch's membrane complex to the choroid-sclera interface. Subsequently, average brightness of the choroidal luminal area (LA) was calculated as the mean reflectivity of three randomly selected choroidal vessels with lumens larger than 100 lm.…”

“…This was followed by choroidal segmentation by manual plotting of choroidal inner and outer border, which highlighted the TCA. The final steps of choroidal LA selection was the same as technique of Sonoda et al 18 Size of LA and TCA were calculated by the software and CVI was computed by dividing LA by TCA.…”