Abstract
Purpose: :
We compared the type and incidence of artifacts in spectral domain (SDOCT; Topcon: 3D-OCT1000) and time domain (TDOCT; Carl Zeiss Meditec: Stratus) OCT images in normal eyes and those with macular disease.
Methods: :
Replicate OCT scans on each eye with each OCT instrument were performed on 73 subjects in a university retina clinic. Subjects diagnoses of AMD =30, DME=16, Vein occlusions =5, no acute disease (normal fellow eyes) =10, other =12. Scans on each machine were performed by experienced operators reading center certified for TDOCT. Decentration (DC), an operator dependent artifact and boundary line (BL) errors, usually an operator independent artifact were primarily assessed. Decentration of the macula by more than 50% outside the central subfield and boundary line errors > 10% of retinal thickness in 5 or more contiguous B scans were considered artifacts causing significantly inaccurate retinal thickness measurements in the central subfield on the SDOCT. With TDOCT, decentration of the center of the macula by more than 10 Ascans from Ascan 64 and BL errors > 10% of the retinal thickness were considered significant. Artifacts such as scan registration error and poor signal strength were also noted.
Results: :
276 scans on SDOCT and 262 scans on TDOCT were evaluated. Significant artifacts were seen in 49 (17.7%) scans taken on the SDOCT machine- DC 22(7.9%), BL errors 18(6.5%), combination of DC and BL errors 1(<1%), others 9(3.2%). On the TDOCT, artifacts were seen in 37(14.1%) scans with DC in 2(<1%), BL errors in 27(10.3%), and others in 8(3%).
Conclusions: :
Operator-dependent artifacts were seen commonly in both OCT types. Non operator-dependent artifacts were comparatively lower in the SDOCT. Additional operator training is likely to reduce the incidence of erroneous central subfield measurements for clinical trials.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)