Evaluation of artifacts associated with macular spectral-domain optical coherence tomography

To characterize the types and frequencies of image artifacts associated with macular scanning using 2 common spectral-domain optical coherence tomography (SD OCT) instruments and to evaluate the impact of artifacts on foveal thickness measurements.

Retrospective, observational chart review.

For the Cirrus HD-OCT (Carl Zeiss Meditec, Dublin, CA), scans of 98 eyes from 58 patients were included in the study. For the Spectralis HRA+OCT (Heidelberg Engineering, Heidelberg, Germany), scans of 88 eyes from 54 patients were included.

Macular volume scans of healthy and diseased eyes were evaluated systematically for image artifacts within each scan overall and within the center 1-mm area. The frequency of each artifact type was compared for scans stratified by diagnosis category. Artifacts in the center 1-mm area were graded for severity and were corrected manually using each instrument's software. Artifacts that resulted in errors of more than 50 microm or more than 10% of retinal thickness or that caused a misdiagnosis of macular edema or retinal thinning were defined as clinically significant and were analyzed further.

Overall frequency of image artifacts by artifact type, relative frequency of artifacts in scans stratified by posterior segment disease diagnosis, and retinal thickness measurements of the center 1-mm subfield before and after artifact corrections.

For Cirrus, 84.7% of scans had artifacts and 32.7% had at least 1 artifact in the center 1-mm area of the scan. For Spectralis, 90.9% of scans had at least 1 artifact, and 37.5% had at least 1 artifact in the center 1-mm area. Certain artifact types were observed more frequently with specific disease states. Clinically significant artifacts involving the center 1-mm area were seen in 5.1% of Cirrus and 8.0% of Spectralis scans.

Image artifacts in SD OCT volume scanning are common and frequently involve segmentation errors. Artifacts are relatively less common in the center 1-mm area of scans, but may affect retinal thickness measurements in a clinically significant manner. Careful review of scans for artifacts is important when using SD OCT images and retinal thickness measurements in patient care or clinical trials.