Repeatability of Vascular Density Measurement of the Three Retinal Plexus Layers Using OCT Angiography in Pathologic Eyes (OCTA Vascular Density Repeatability of Three Plexus Layers)

Figures & data

Figure 1 Optical coherence tomography (OCT) and OCT angiography (OCTA) images of the retinal vascular capillary plexus layers and macular zones on the ETDRS map. (A–C) Cross-sectional B-scan OCT images showing segmentation of the various retinal plexus layer including automated-segmentation of (A) the superficial capillary plexus (SCP; red and green lines outline the border) and (B) deep capillary plexus (DCP; red and green lines outline the border), (C) custom-segmented intermediate capillary plexus (cICP; red and green lines outline the border), and (D) custom-segmented deep capillary plexus (cDCP; two red lines outline the border). (E) An example of a 6x6 mm OCTA image of the DCP showing flow detected on an en face ETDRS map which includes the inner 1 mm circle (“fovea”), inner 3 mm ring and outer 6 mm ring. (F) An example of 3x3 mm OCTA image of the SCP showing flow detected on an enface ETDRS map of the macula, the inner 1 mm circle (ie, “fovea”) and inner 3 mm ring. (Overall ETDRS refers to the total 3 mm circle for the 3x3 mm scan and 6 mm circle for the 6x6 mm scan).

Table 1 Demographics and Clinical Characteristics of the Good Image Cohorts for Each Scan Size and Total Cohort. P-value Shown Compares the Total Cohort to the Good Image Cohort

	3x3 mm OCTA (n=54 Eyes)	6x6 mm OCTA (n=47 Eyes)	Total Cohort (n=86 Eyes)
Patients	34	32	45
Mean Age (years, range)	58.2 (19.6–86.7)	55.8 (19.6–86.7)	59.8 (19.6–86.7)
Female (%)	20 (59%)	23 (72%)	25 (56%)
Pathology (eyes)
Normal	8	7	13
Vasculopathy   Diabetes   Vascular occlusion   Other	31 21 7 3	25 16 7 2	54 36 12 6
Optic neuropathy   Papilledema   Optic atrophy	15 10 5	15 10 5	21 10 11
Mean visual acuity [logMAR±SD, (range)]  Normal  Vasculopathy without CME  Vasculopathy with CME  Optic Neuropathy	0.22±0.26 (0–1.3) (n=54) (P=0.33) 0.08±0.09 (0–0.2) (n=8) (P=0.47) 0.23±0.23 (0–1.0) (n=15) (P=0.24) 0.35±0.33 (0–1.3) (n=16) (P=0.93) 0.16±0.21 (0–0.6) (n=15) (P=0.86)	0.20±0.22 (0–1.0) (n=47) (P=0.15) 0.11±0.23 (0–0.3) (n=7) (P=0.93) 0.26±0.25 (0–1.3) (n=13) (P=0.41) 0.24±0.16 (0–0.55) (n=12) (P=0.20) 0.15±0.19 (0–0.6) (n=15) (P=0.99)	0.27±0.27 (0–1.3) (n=88) 0.11±0.10 (0–0.3) (n=13) 0.35±0.32 (0–1.3) (n=25) 0.34±0.27 (0–1.3) (n=29) 0.16±0.20 (0–0.6) (n=21)
Mean central macular thickness (µm)  Normal  Vasculopathy without CME  Vasculopathy with CME	286.41±57.06 (n=39) (P=0.81) 251.71±23.27 (n=8) (P=0.89) 280.67±43 (n=15) (P=0.36) 311.47±69.77 (n=16) (P=0.72)	278.63±42.85 (n=32) (P=0.39) 254.83±23.24 (n=7) (P=0.88) 282.00±50 (n=13) (P=0.44) 292.92±34 (n=12) (P=0.65)	289.26±63.23 (n=68) 253.20±21.51 (n=10) 298.72±66.6 (n=22) 302.96±72.33 (n=25)

Abbreviations: CME, cystoid macular edema; OCTA, optical coherence tomography angiography.

Table 2 Repeatability of Vascular Density Measurement for the Total Cohort (A, All Enrolled Eyes) and for the Good Image Cohort (B, Subset of Eyes with OCTA Signal Strength ≥6) for the 3x3 mm and 6x6 mm OCTA Scans

A. Repeatability of Vascular Density Measurement for all Enrolled Eyes
3x3 mm (n=86)	CV, Mean (SD)%				ICC (95% CI)
	SCP	DCP	cDCP	cICP	SCP	DCP	cDCP	cICP
ETDRS	6.0 (5.5)	9.2 (2.6)	13.6 (27.0)	9.0 (9.5)	0.853 (0.751–0.902)	0.665 (0.529–0.768)	0.419 (0.229–0.579)	0.662 (0.522–0.767)
6x6 mm (n=86)	CV, Mean (SD)%				ICC (95% CI)
	SCP	DCP	cDCP	cICP	SCP	DCP	cDCP	cICP
ETDRS	6.4 (15.4)	7.5 (15.7)	12.3 (25.6)	6.4 (10.9)	0.651 (0.511–0.758)	0.697 (0.570–0.792)	0.744 (0.633–0.826)	0.820 (0.736–0.878)
B. Repeatability of Vascular Density Measurement for Eyes with OCTA Signal Strength ≥6
3x3 mm (n=54)	CV, Mean (SD)%				ICC (95% CI)
	SCP	DCP	cDCP	cICP	SCP	DCP	cDCP	cICP
ETDRS	3.6 (2.7)	3.3 (3.1)	9.8 (19.9)	6.8 (6.2)	0.918 (0.862–0.952)	0.637 (0.448–0.772)	0.759 (0.617–0.854)	0.772 (0.603–0.873)
Fovea	10.0 (8.9)	6.3 (9.1)	12.7 (10.5)	7.9 (7.0)	0.897 (0.829–0.939)	0.892 (0.820–0.936)	0.720 (0.561–0.827)	0.843 (0.719–0.914)
3 mm inner ring	3.6 (2.6)	3.5 (3.5)	6.7 (6.6)	6.9 (6.2)	0.921 (0.867–0.954)	0.877 (0.796–0.927)	0.699 (0.531–0.851)	0.772 (0.609–0.871)
FAZ size	12 (31)				0.935 (0.891–0.962)
6x6 mm (n=47)	CV, Mean (SD)%				ICC (95% CI)
	SCP	DCP	cDCP	cICP	SCP	DCP	cDCP	cICP
ETDRS	3.2 (2.7)	3.6 (3.0)	4.8 (5.6)	5.6 (5.4)	0.929 (0.875–0.960)	0.697 (0.514–0.819)	0.609 (0.380–0.767)	0.689 (0.489–0.820)
Fovea	10.3 (8.7)	7.9 (10.0)	14.3 (15.6)	10.4 (12.9)	0.863 (0.800–0.933)	0.752 (0.595–0.854)	0.416 (0.149–0.626)	0.508 (0.241–0.702)
3 mm inner ring	3.7 (2.8)	2.6 (2.2)	5.1 (7.0)	6.4 (6.6)	0.929 (0.876–0.960)	0.927 (0.873–0.959)	0.529 (0.288–0.707)	0.549 (0.295–0.730)
6 mm outer ring	6.4 (20.3)	4.2 (3.7)	7.9 (20.6)	5.4 (5.4)	0.666 (0.471–0.799)	0.703 (0.523–0.823)	0.405 (0.136–618)	0.737 (0.559–0.850)
FAZ size	9.6 (15)				0.921 (0.862–0.956)

Abbreviations: CV, coefficient of variation; ICC, intraclass coefficient; SCP, superficial capillary plexus; DCP, deep capillary plexus; cDCP, custom-segmented deep capillary plexus; FAZ, foveal avascular zone; cICP, custom-segmented intermediate capillary plexus; ETDRS, early treatment of diabetic retinopathy study macular region 6 mm diameter centered in fovea.

Table 3 Repeatability of Macular Vascular Density Measurement Obtained Using OCTA for Eyes with and without CME or Retinal Vasculopathy. (A) 3x3 mm OCTA Scans. (B) 6x6 mm OCTA Scans

A. Repeatability of Macular Vascular Density Measurement for 3x3 mm OCTA Scans
3x3 mm Scan	CME (n=16)		No CME (n=38)		Vasculopathy without CME (n=15)
	CV, Mean (SD)%	ICC (95% CI)	CV, Mean (SD)%	ICC (95% CI)	CV, Mean (SD)%	ICC (95% CI)
SCP
ETDRS	4.5 (3.3)	0.883 (0.687–0.959)	3.3 (2.4)	0.902 (0.820–0.948)	3.4 (2.6)	0.909 (0.752–0.969)
Fovea	11.5 (7.2)	0.885 (0.702–0.958)	9.4 (9.5)	0.908 (0.831–0.951)	10.2 (9.6)	0.914 (0.764–0.970)
3 mm inner ring	4.1 (2.8)	0.903 (0.737–0.966)	3.3 (2.5)	0.899 (0.815–0.946)	3.4 (2.6)	0.912 (0.758–0.969)
DCP
ETDRS	4.0 (4.1)	0.188 (−0.323–0.615)	3.0 (2.6)	0.806 (0.657–0.894)	3.2 (2.7)	0.858 (0.630–0.950)
Fovea	9.9 (15.7)	0.747 (0.414–0.904)	4.8 (2.9)	0.953 (0.912–0.976)	6.2 (3.4)	0.940 (0.832–0.980)
3 mm inner ring	4.5 (4.6)	0.804 (0.511–0.930)	3.1 (2.9)	0.783 (0.620–0.881)	3.2 (3.1)	0.843 (0.595–0.944)
cDCP
ETDRS	13.4 (35.6)	0.342 (−0.187–0.717)	8.2 (7.4)	0.877 (0.776–0.934)	6.8 (5.1)	0.933 (0.814–0.977)
Fovea	10.7 (7.2)	0.840 (0.600–0.941)	13.5 (11.7)	0.613 (0.369–0.779)	14.5 (12.7)	0.581 (0.118–0.837)
3 mm inner ring	4.3 (3.9)	0.836 (0.580–0.942)	7.6 (7.2)	0.666 (0.443–0.811)	6.4 (4.9)	0.772 (0.446–0.917)
cICP
ETDRS	5.7 (3.2)	0.746 (0.316–0.920)	7.2 (7.1)	0.777 (0.525–0.895)	5.7 (5.9)	0.857 (0.488–0.969)
Fovea	3.6 (3.8)	0.944 (0.825–0.983)	9.6 (7.3)	0.800 (0.608–0.901)	9.8 (5.3)	0.883 (0.516–0.976)
3 mm inner ring	6.1 (3.5)	0.749 (0.322–0.921)	7.3 (7.1)	0.771 (0.537–0.889)	6.3 (6.4)	0.827 (0.399–0.962)
FAZ size	24.2 (48.2)	0.958 (0.885–0.985)	7.5 (20.4)	0.884 (0.787–0.938)	15.2 (31.2)	0.800 (0.502–0.928)

B. Repeatability of Macular Vascular Density Measurement for 6x6 mm OCTA Scans
6x6 mm Scan	CME (n=12)		No CME (n=35)		Vasculopathy without CME (n=13)
	CV, Mean (SD)%	ICC (95% CI)	CV, Mean (SD)%	ICC (95% CI)	CV, Mean (SD)%	ICC (95% CI)
SCP
ETDRS	4.4 (2.9)	0.837 (0.503–0.953)	2.8 (2.5)	0.936 (0.877–0.967)	2.8 (1.6)	0.947 (0.836–0.984)
Fovea	16.1 (8.0)	0.723 (0.282–0.911)	8.4 (8.2)	0.937 (0.878–0.968)	9.1 (5.2)	0.939 (0.812–0.981)
3 mm inner ring	4.5 (2.9)	0.859 (0.584–0.957)	3.4 (2.7)	0.923 (0.852–0.960)	4.3 (2.6)	0.914 (0.744–0.973)
6 mm outer ring	16.1 (39.6)	0.257 (−0.345–0.709)	3.1 (2.8)	0.925 (0.857–0.961)	3.3 (2.1)	0.917 (0.752–0.974)
DCP
ETDRS	3.5 (2.1)	0.928 (0.757–0.980)	3.6 (3.3)	0.844 (0.712–0.918)	4.9 (4.1)	0.822 (0.514–0.942
Fovea	15.6 (16.6)	0.399 (−0.198–0.780)	5.3 (4.5)	0.916 (0.841–0.957)	7.1 (5.7)	0.837 (0.551–0.947)
3 mm inner ring	3.6 (2.3)	0.902 (0.697–0.971)	2.3 (2.1)	0.900 (0.810–0.948)	2.9 (2.6)	0.898 (0.699–0.968)
6 mm outer ring	3.7 (2.3)	0.912 (0.709–0.976)	4.5 (4.1)	0.816 (0.665–0.902)	5.6 (3.5)	0.793 (0.452–0.932)
cDCP
ETDRS	7.3 (9.9)	0.574 (−0.430–0.874)	4.1 (3.4)	0.492 (0.183–0.712)	3.8 (3.5)	0.427 (−0.198–0.805)
Fovea	25.6 (22.3)	0.058 (−0.511–0.592)	10.4 (10.4)	0.736 (0.5537–0.857)	12.5 (11.4)	0.499 (−0.046–0.815)
3 mm inner ring	7.6 (12.9)	0.400 (−0.197–0.780)	4.2 (3.0)	0.624 (0.371–0.791	3.4 (2.3)	0.701 (0.269–0.898)
6 mm outer ring	18.3 (39.6)	0.216 (−0.383–0.687)	4.3 (3.6)	0.509 (0.216–0.718)	4.1 (4.1)	0.483 (−0.67–0.808)
cICP
ETDRS	5.9 (6.2)	0.774 (0.376–0.933)	5.5 (5.1)	0.338 (−0.002–0.611)	6.7 (7.0)	0.493 (−0.097–0.850)
Fovea	18.1 (22.2)	0.256 (−0.406–0.730)	7.7 (5.9)	0.735 (0.517–0.863)	12.4 (7.7)	0.147 (−0.231–0.640)
3 mm inner ring	9.6 (10.1)	0.451 (−0.074–0.806)	5.2 (4.6)	0.566 (0.276–0.763)	6.6 (5.3)	0.525 (−0.055–0.861)
6 mm outer ring	6.5 (6.1)	0.769 (0.332–0.937)	5.1 (5.2)	0.416 (0.095–0.663)	7.3 (8.0)	0.430 (−0.135–0.822)
FAZ size	19.1 (25.0)	0.895 (0.677–0.969)	6.5 (7.3)	0.957 (0.916–0.978)	7.8 (8.0)	0.935 (0.792–0.981)

Abbreviations: CV, coefficient of variation; ICC, intraclass coefficient; SCP, superficial capillary plexus; DCP, deep capillary plexus; cDCP, custom-segmented deep capillary plexus; FAZ, foveal avascular zone, cICP, custom-segmented intermediate capillary plexus; CME, cystoid macular edema; ETDRS, early treatment of diabetic retinopathy study macular region 6 mm diameter centered in the fovea.