Measurement of Vessel Density Using Optical Coherence Tomography-angiography in Normal Subjects: Difference by Analysis Area

Jong Chan Im

doi:10.3341/jkos.2019.60.4.355

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Im: Measurement of Vessel Density Using Optical Coherence Tomography-angiography in Normal Subjects: Difference by Analysis Area

Original Article

Journal of the Korean Ophthalmological Society 2019; 60(4): 355-361.

Published online: 17 April 2019

DOI: https://doi.org/10.3341/jkos.2019.60.4.355

Measurement of Vessel Density Using Optical Coherence Tomography-angiography in Normal Subjects: Difference by Analysis Area

Jong Chan Im, MD

Department of Ophthalmology, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, Korea.

Address reprint requests to Jong Chan Im, MD. Department of Ophthalmology, Samsung Changwon Hospital, #158 Paryong-ro, Masanhoewon-gu, Changwon 51353, Korea. Tel: 82-55-233-5400, Fax: 82-55-233-8357, ijc81@hanmail.net

Received 6 September 2018 Revised 27 October 2018 Accepted 18 March 2019

The Korean Ophthalmological Society

(open-access):

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Purpose

To evaluate the vessel density of macula according to analysis area in health subjects using optical coherence tomography angiography (OCTA).

Methods

We retrospectively analyzed 30 eyes of 20 healthy people who underwent OCTA. We measured vessel density (VD) according to analysis area and foveal avascular zone (FAZ) size of superficial capillary plexus (SCP) and deep capillary plexus (DCP). The analysis areas were classified as 3 × 3 mm scan area (Box), Box area excluding FAZ (Box-FAZ), fovea centered 3 mm circle area (Circle), Circle area excluding FAZ (Circle-FAZ) and area between fovea centered 1 mm circle and 3 mm circle (Ring).

Results

The SCP VDs were Box 34.00 ± 3.97, Box-FAZ 35.37 ± 4.09, Circle 31.70 ± 4.56, Circle-FAZ 33.34 ± 4.72, and Ring 35.22 ± 5.09. The DCP VDs were Box 30.04 ± 3.51, Circle 29.49 ± 3.57, Box-FAZ 31.59 ± 3.65, Circle-FAZ 31.46 ± 3.72, and Ring 32.60 ± 4.00. There was a significant difference according to analysis area from both SCP and DCP (p < 0.001 and p < 0.001, respectively). Comparison of the vessel density between SCP and DCP in the same analysis area were different in all areas (p < 0.001, p = 0.001, p < 0.001, p = 0.005, p = 0.001, respectively).

Conclusions

This study shows different results according to analysis area when measuring VD using OCTA. Therefore, when comparing studies related to VD, it is necessary to pay attention to the analysis area in the interpretation of the results.

Keywords: Analysis area, Foveal avascular zone, Healthy subjects, Optical coherence tomography angiography, Vessel density

Figures and Tables

Figure 1

Optical coherence tomography angiography analysis areas. (A) Manual drawing of the foveal avascular zone (FAZ) area (gray) and boundary (white dot line). (B) Fovea centered 3 × 3 mm scan (Box). (C) Box area excluding FAZ (Box-FAZ). (D) Fovea centered 3 mm circle area (Circle). (E) Circle area excluding FAZ (Circle-FAZ). (F) Area between foveal centered 1 mm circle and 3 mm circle (Ring).

Figure 2

Zones divided by distance from the fovea. (A) Fovea centered 1 mm circle area (zone A). (B) Area between fovea centered 1 mm circle and 3 mm circle (zone B). (C) 3 × 3 mm scan area excluding foveal centered 3 mm circle (zone C).

Table 1

Baseline characteristics of the study participants

Values are presented as mean ± standard deviation unless otherwise indicated.

BCVA = best corrected visual acuity; logMAR = logarithm of the minimum angle of resolution; IOP = intraocular pressure; SE = spherical equivalent; CSFT = central subfield foveal thickness; SCP = superficial capillary plexus; FAZ = foveal avascular zone; DCP = deep capillary plexus.

Table 2

Comparison of the vessel density in the superficial capillary plexus and deep capillary plexus according to analysis area

Values are presented as mean ± standard deviation unless otherwise indicated.

SCP = superficial capillary plexus; VD = vessel density; DCP = deep capillary plexus; FAZ = foveal avascular zone.

^*p-values derived from paired t-test; ^†p-values derived from repeated measures analysis of variance.

Table 3

Comparison of the vessel density in superficial capillary plexus and deep capillary plexus according to zones

Values are presented as mean ± standard deviation unless otherwise indicated.

SCP = superficial capillary plexus; VD = vessel density; DCP = deep capillary plexus.

^*p-values derived from paired t-test; ^†p-values derived from repeated measures analysis of variance.

Notes

^{Conflicts of Interest} The authors have no conflicts to disclose.

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