Table 1.
Quantitative OCTA Studies of Capillary Abnormalities in Diabetic Retinopathy
| Reference | Eyes/pts DM Eyes/pts HC | DR Severity (no. of eyes) | Vessel Density Lower in DR vs Control | Trend with DR Severity | FAZ Larger in DR vs Control | Projection Artifact Removal | Segmentation, Density Type, Methods | Device |
|---|---|---|---|---|---|---|---|---|
| (Agemy et al., 2015). | 55 of 34 21 of 12 |
11 mild NPDR, 9 moderate NPDR, 9 severe NPDR, 26 PDR | SCP and DCP (P<0.05) | (P<0.05) | NA | Not performed | Skeletonized vessel density | RTVue, SD-OCTA (840 nm) |
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| (Al-Sheikh et al., 2016). | 28 of 18 40 of 22 |
10 mild NPDR, 10 moderate NPDR, 2 severe NPDR, 6 PDR, (13 had DME) | SCP (P<0.001), DCP (P=0.028) | NA | SCP (P=0.003), DCP (P<0.001) | Not performed | Vessel density, DCP segmented to included only the inner nuclear layer | Topcon SS-OCTA (1050 nm) |
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| (Bhanushali, et al., 2016). | 209 of 122 60 of 31 |
35 mild NPDR, 95 moderate NPDR, 57 severe NPDR, 22 PDR, Controls were younger with higher female percentage | SCP and DCP (P<0.001) | None | SCP and DCP (P=0.001) | Not performed | Fractal = distance b/t large and small vessels, Vessel density; Gender and age difference not corrected for | RTVue SD-OCTA (840 nm) |
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| (de Carlo, et al., 2015). | 61 of 39 28 of 22 |
61 NoDR | NA | NA | Full thickness “DM NoDR” vs “Control” (P=0.04) | Not performed | FAZ area, FAZ remodeling, Non-perfusion | RTVue SD-OCTA (840 nm) |
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| (Di, et al., 2016). | 113 of 65 85 of 62 |
53 NoDR, 45 NPDR, 15 PDR | NA | NA | Full thickness “DM NoDR” vs “Control” (P=0.04) | Not performed | FAZ: area, vertical radius (VR), and horizontal radius (HR) | RTVue SD-OCTA (840 nm) |
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| (Freiberg, et al., 2015a). | 29 of 15 25 of 22 |
18 NPDR, 4 pre-PDR, 13 PDR | NA | NA | MFD SCP (P=0.008), DCP (P<0.001) | Not performed | Maximum FAZ diameter (MFD) | RTVue SD-OCTA (840 nm) |
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| (Hwang, et al., 2016a). | 12 of 12 12 of 12 |
2 mild NPDR, 1 moderate NPDR, 9 PDR | NA | Total avascular area detects DR with 100% specificity (AROC = 1) | FAZ area detects DR with 50% specificity (AROC = 0.77) | Not performed | Automated avascular quantification, Area under receiver operating curve (AROC), 6×6 | RTVue SD-OCTA (840 nm) |
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| (Hwang, et al., 2016b). | 47 of 29 29 of 15 |
11 mild to moderate NPDR, 13 severe NPDR, 23 PDR | 100% sensitivity and specificity detect DR with PR-OCTA of all 3 plexuses | NA | NA | PR-OCTA | Sensitivity and Specificity of detecting DR better with PR-OCTA, Custom segmentation | RTVue SD-OCTA (840 nm) |
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| (Ishibazawa et al., 2015). | 47 of 25 0 controls |
11 mild NPDR, 13 moderate NPDR, 12 severe NPDR, 11 PDR | SCP ischemia was greater than DCP ischemia (P=0.018) | NA | NA | Not performed | Manually traced ischemic area | RTVue SD-OCTA (840 nm) |
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| (Kim et al., 2016). | 84 of 50 14 of 8 |
32 mild NPDR, 16 severe NPDR, 36 PDR | Less parameters significantly different between sup-groups in DCP compared to SCP. | Parameters: VD, SD, FD, VDI correlated with DR severity – most were (p<0.05) | NA | Not performed | Vessel density (VD), Skeletonized vessel density (SD), Fractal dimension (FD), Vessel diameter index (VDI) | Cirrus SD-OCTA (840 nm) |
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| (Lin, et al., 2016). | 51 of 33 0 controls |
17 NoDR to mild NPDR, 21 moderate to severe NPDR, 13 PDR | NA | Full Thickness: PI decrease with DR severity (p<0.001 to 0.862) | NA | Not performed | Perfusion index (PI) = % coverage of vessels (vessel density) | Cirrus SD-OCTA (840 nm) |
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| (Salz, et al., 2016). | 43 of 30 11 of 6 |
13 NoDR, 11 mild NPDR, 6 moderate NPDR, 5 severe NPDR, 8 PDR | More MAs in DCP than SCP. Full Thickness PIA: Higher in DM vs Control (P<0.001), PDR vs NoDR (P<0.05), and PDR vs NPDR (P<0.05) | NA | DM vs Control (P<0.001), PDR vs NoDR (P<0.05), and PDR vs NPDR (P<0.05) | Not performed | FAZ area, Perifoveal intercapillary area (PIA) | Prototype SS-OCTA (1060 nm) |
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| (Samara et al., 2016). | 84 of 55 34 of 27 |
32 mild NPDR, 31 moderate to severe NPDR, 21 PDR, (No DME) | SCP (P<0.001), DCP (P<0.001) | VLD, VAD, FAZ correlated with VA for SCP & DCP (p<0.001) | SCP (p<0.01), DCP (P<0.001) | Not performed | FAZ area, Vessel area density (VAD), Vessel length density (VLD) | RTVue SD-OCTA (840 nm) |
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| (Schottenhamml, et al., 2016). | 21 of 21 5 of 5 |
7 NoDR, 9 NPDR, 5 PDR | NA | Full Thickness: General intercapillary area increased with DR severity | Less difference between groups when FAZ was included in analysis | Not performed | Mean largest 10 and 20 intercapillary areas; Vesselness filter; No statistics | Prototype SS-OCTA (1050 nm) |
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| (Takase, et al., 2015). | 44 eyes 19 eyes |
24 NoDR, 17 mild NPDR, 3 moderate NPDR | NA | NA | All DM vs controls: SCP (P<0.01), DCP (P<0.01), NoDR vs Control (P<0.01) | Not performed | Manually traced FAZ area | RTVue SD-OCTA (840 nm) |
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| (Zahid et al., 2016). | 13 of 8 56 of 29 |
5 mild NPDR, 8 PDR (No DME), Controls were younger | SCP (P<0.05), DCP (P<0.05), plus fractal | NA | NA | Not performed | Fractal dimensional analysis, Vessel density; Age difference not corrected for | RTVue SD-OCTA (840 nm) |
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| (Zhang, et al., 2016b). | 13 of 13 13 of 13 |
13 mild NPDR, Controls were younger | Segmented angiograms distinguish better, SCP: EAA (P<0.001) and TAA (P=0.007); DCP: EAA (P<0.001) and TAA (P=0.022) |
NA | NA | PR-OCTA | Total (TAA) and Extrafoveal avascular area (EAA), Vesselness filter; Age difference not corrected for | RTVue SD-OCTA (840 nm) |
Definitions: AROC = Area under receiver operating curve; DCP = Deep capillary plexus; DM = Diabetes mellitus; DME = Diabetic macular edema; DR = Diabetic retinopathy; EAA = Extrafoveal avascular area; FAZ = Foveal avascular zone; FD= Fractal dimension; HC = Healthy controls; HR = Horizontal radius of the foveal avascular zone; MA = Microaneurysm; MCP = Middle capillary plexus; MFD = Maximum foveal avascular zone diameter; NA = Not applicable (parameter not measured in the study); NoDR = Diabetes mellitus without diabetic retinopathy; NPDR = Non-proliferative diabetic retinopathy; PDR = Proliferative diabetic retinopathy; PI = Perfusion index (vessel density); PIA = Perifoveal intercapillary area; PR-OCTA = Projection-resolved optical coherence tomography angiography; Pts = Patients; SCP = Superficial capillary plexus; SD = Skeletonized vessel density; SD-OCTA = Spectral-domain optical coherence tomography angiography; Sig. = statistically significant; SS-OCTA = Swept-source optical coherence tomography angiography; TAA = Total avascular area; VA = Visual acuity; VAD = Vessel area density; VD = Vessel density; VDI = Vessel diameter index; VLD = Vessel length density; Vesselness filter = Enhances vessels by correcting for fluctuations in structural OCT signal intensity and by suppressing background noise; VR = Vertical radius of the foveal avascular zone.