Quality Issues in Interpretation of Optical Coherence Tomograms in Macular Diseases

Abstract

Artifacts causing erroneous reported centerpoint thickness are common. Identifying clues that indicate suboptimal quality of optical coherence tomography (OCT) images are important to avoid erroneous interpretation of OCT data in clinical trials.

Imaging of Diabetic Retinopathy and Diabetic Macular Edema

“…Artifacts that create erroneous thickness reports occur in around 15% of OCT scans in eyes with DME (in both TD-and SD-OCT) [12][13][14]. The main artifacts seen are boundary (segmentation) line errors and decentration.…”

“…In some cases, this may make the assessment whether the macular measurement grid is appropriately centered on the fovea difficult. The net effect of these artifacts is inaccuracy in the instrument-generated retinal thickness measurements [12]. Clinicians should be knowledgeable about such problems to determine the reliability of an individual's retinal thickness measurements.…”

“…Among the causes for boundary line errors are low signal/noise ratio of the scan or markedly distorted macular anatomy due to cysts, subretinal fluid, intraretinal hemorrhage, or epiretinal membranes. When recognized, manual correction of the erroneous measurements is often possible [12,14].…”

Stratus OCT Quality Control in Two Multi-Centre Multiple Sclerosis Clinical Trials

“…Many of the issues encountered in Trial 1 we believe could have been avoided had our reading centre been involved at the beginning of the MS clinical trial. Signal strength and the presence of artifacts have been shown to affect RNFL thickness measurements using Stratus OCT. [15][16][17]30,31 In summary, the quantitative data and examples in Figures 1 to 4 demonstrate the utility of an OCT reading centre in MS clinical trials using OCT technology to monitor MS patients with RNFL or macula volume changes. To optimise data quality, it seems essential for an OCT reading centre to be involved from the earliest planning stages of the trial to ensure technicians are properly certified for OCT testing.…”

Optical Coherence Tomography Findings in Diabetic Macular Edema

“…All these artifacts have been recognized to cause breakdown in the performance of the segmentation software and thus leading to incorrect automated retinal thickness measurements (Ho et al, 2009;Ray et al, 2005;Sadda et al, 2006). Several studies have pointed out that segmentation breakdown may also be possible in high quality scans if there are pathological features such as full-thickness macular hole, pigment epithelial detachment, subretinal fluid, retinal fibrosis and hard exudates (Domalpally et al, 2009;Ho et al, 2009;Krebs et al, 2009;Sadda et al, 2006). The presence of media opacities (cataract, vitreous hemorrhage, ect.)…”