Imaging artifacts can impact your interpretation of disease progression—but to what degree? A recent study helps to answer this question with a review of SD-OCT raw B-scans to determine whether artifacts impacted the original interpretation of progression, based on auto-segmented change maps.

The retrospective review included glaucoma and glaucoma suspect eyes, imaged with SD-OCT during a one-month period. All cases had multiple sets of RNFL and macular images. The review also assessed co-prevalence of artifacts in the RNFL and macula, and the association of clinical factors with the likelihood of artifacts.

The study included 190 eyes with 760 sets of OCT RNFL and macular scans. Half of the eyes had artifacts either in the circumpapillary RNFL or in the macula. The most common artifacts were epiretinal membrane and vitreomacular traction.

Among the study eyes, true progression was present on about 40% of the scans. Among the 96 eyes that had artifacts, 23 artifacts masked true progression, 35 led to a false positive and 38 had no effect on the interpretation of progression. The researchers found that the presence of true progression on the RNFL scan was significantly associated with the true progression on the macular scan. Artifacts on the RNFL scan were also significantly associated with artifacts on the macular scan. Other factors significantly associated with the presence of artifacts on RNFL scans were severe glaucoma, hypertension and age.

“Artifacts lead to false positive and false negative interpretations of progression when using only the autosegmentation change maps,” the researchers pointed out. They added that careful examination of the raw B-scan images of both the RNFL and macula are important for identifying artifacts and true glaucoma progression.

Li A, Thompson AC, Asrani S. Impact of artifacts from optical coherence tomography retinal nerve fiber layer and macula scans on detection of glaucoma progression. Am J Ophthalmology. August 17, 2020. [Epub ahead of print].