Abstract
Purpose: :
To investigate artifacts of OCT–scans and of software analysis for retinal cross section scans in a specialized retina clinic setting.
Methods: :
A total of 205 vertical cross–hair OCT–Scans of retinal Stratus OCTs were randomly chosen from the database. All scans had been performed by one experienced technician. There were 75 (37%) normal findings, the remaining scans showed various types of retinal pathology: macular edema (57), diseases of the vitreoretinal interface such as macular pucker (31), macular holes (21), 16 age–related macular degeneration, and 5 central serous choroidopathy. All scanning artifacts were analyzed. Retinal thickness of all scans was measured automatically at the center of the macula using two different software algorithms: the instrument's built–in "Stratus OCT Viewer V 4.01" and the stand–alone application "Datamedical OCTview V 3.5". Errors of the software to correctly identify the retinal surface and the outer highly–reflective layer were assigned into three categories: none, minor error (no influence on measurements) and major error.
Results: :
A total of 7.3 % of all OCT–scans showed scanning artifacts: 5 motion artifacts, 9 scans with low signal intensity and 1 de–centered scan. Scanning artifacts significantly increased the frequency of software–errors (each p=0.012). Presence of retinal pathology also increased the number of errors (p=0.004 for Stratus OCT viewer and p=0.01 for Datamedical). Software analysis yielded a total of 20 major and 2 minor errors for the Stratus OCT and 32 major and 64 minor errors for the Datamedical viewer (p<0.001). The minor errors mostly represented surface irregularities caused by less smoothing.
Conclusions: :
Scanning artifacts were associated with a significantly higher frequency of software errors. The Datamedical OCT viewer is more susceptible for minor artifacts, however, in contrast to the Stratus OCT viewer manual corrections are possible. As artifacts of scans and software occur frequently the interpretation of OCT scans requires special attention on artifacts.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • retina