J Korean Ophthalmol Soc.  2010 Aug;51(8):1084-1091.

Analysis of Various Artifacts Produced by Spectral-Domain Optical Coherence Tomography Based on Macular Pathologies

• Shin YW
• Lee JH
• Jun JY
• Song Y
• Cho HY
• Lee BR

Abstract

PURPOSE
To report the frequency, severity and various types of artifacts associated with spectral-domain optical coherence tomography (SD-OCT) based on macular pathologies.
METHODS
Data was collected retrospectively from 116 eyes of 116 subjects. SD-OCT (3D-1000, Topcon Corp., Japan) imaging was performed in 40 healthy eyes, 45 eyes with intraretinal pathology (IRP) and 31 eyes with subretinal pathology (SRP). The scan protocol was 12x6 mm radial scan. The frequency and types of artifacts were investigated in each scan and were analyzed based on macular disease. Additionally, the effect of artifacts on the measurement of macular thickness was studied.
RESULTS
Errors occurred in 77 eyes (66.38%). Inner retinal boundary misidentification (IRBM) was the most common error (25.86%), with the frequencies of other types of artifacts being 10.34% for off-center fixation, 15.52% for degraded image and 8.6% for outer retinal boundary misidentification (ORBM). The overall error rate of SD-OCT in the retinal pathology group was much higher than that in the normal group. Macular thickness was underestimated in the IRP group because the outer retinal boundary of the IRP group tended to be misidentified toward the inner retina (p<0.01).
CONCLUSIONS
SD-OCT can frequently cause various types of artifacts in patients with macular disease. When interpreting OCT images, the artifacts of SD-OCT should be considered in order to obtain accurate macular thickness and to prevent erroneous clinical decisions.

Keyword

Artifact; Macular disease; Segmentation error; Spectral domain optical coherence tomography

MeSH Terms

Artifacts
Eye
Humans
Retina
Retinaldehyde
Retrospective Studies
Tomography, Optical Coherence
Retinaldehyde

Figure

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  Figure 1. Type of artifacts of Fourier-domain OCT in current study. (A) IRBM, inner retina boundary misidentification. (B) ORBM, outer retinal boundary misidentification. (C) Off center fixation: white arrow, center of OCT; yellow arrow; center of retina. (D) Degraded image, note that Q factor of this image is 30.98, which means signal strength of OCT is low.

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  Figure 2. Examples of artifact scoring. (A) OCT image shows inner retina boundary misidentification of central macula. 1 point is given due to presence of error. Because deviations of horizontal and vertical line are more than two thirds of the central macula respectively, 4 points are added. Therefore, the sum of error scores in this scan is 5 points. (B) OCT image shows outer retina boundary misidentification of the outer macula. One point is given due to presence of error. Only 1 point is added because deviation of the horizontal line is less than one third of the outer macula and deviation of the vertical line is from one third to two thirds of the outer macula. The sum of error score is 2 points.

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  Figure 3. Examples of wrong measured MT. (A) Overestimation of MT due to IRBM. (B) Overestimation of MT due to ORBM. (C) Underestimation of MT due to IRBM. (D) Underestimation of MT due to ORBM. MT=macular thickness; IRBM=inner retina boundary misidentification; ORBM=outer retina boundary misidentification.

Reference

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