Abstract
Purpose :
To assess the prevalence of segmentation errors and motion artifacts in optical coherence tomography angiography (OCT-A) in different retinal diseases.
Methods :
In a retrospective analysis, multimodal retinal imaging including OCT-A was performed in one eye of 57 healthy controls (50.96 ± 22.4 years) and 138 patients (66.6 ± 14.3 years) affected by different chorioretinal diseases (early/ intermediate age-related macular degeneration (AMD, n=26), neovascular AMD (nAMD, n=22), geographic atrophy due to AMD (GA, n=6), glaucoma (n=28), central serous chorioretinopathy (CSC, n=14), epiretinal membrane (EM, n=26) and retinopathia pigmentosa (RP, n=16)). Central 3x3 mm2 OCT-A imaging was performed with active eye-tracking (AngioVue, Optovue). Best-corrected visual acuity (BCVA) and signal strength index (SSI) were recorded. Images were independently evaluated by two graders using the OCT-A motion artifact score (MAS, Score I - IV) as well as a newly introduced segmentation accuracy score (SAS, Score I – II B).
Results :
Mean SSI was 63.94 ± 9.2 showing a negative correlation with increasing age (p<0.001). In the healthy cohort, mean MAS was 1.45 ± 0.8 and segmentation was accurate (SAS I) in all eyes. In eyes with retinal pathologies, mean MAS was 2.07 ± 0.9 (p<0.001). Lowest MAS was observed in GA (2.67 ± 0.5) and RP (2.44 ± 0.7). In 35.5% of all patients, segmentation was accurate. 64.5% showed segmentation errors in more than 5% of all single b-scans in one (SAS II A, n=49) or at least two (SAS II B, n=40) segmentation boundaries. Highest percentages of inaccurate segmentation (90.9%) and SAS II B (63.6%) were observed in the nAMD group. The inner plexiform layer was the segmentation boundary most prone to inaccurate segmentation in all pathologies compared to inner limiting membrane (ILM) and choriocapillaris segmentation. Incorrect ILM segmentation was only seen in patients with EM.
Conclusions :
Prior to both qualitative and quantitative analysis, OCT-A images must be carefully reviewed after recording as motion artifacts and segmentation errors in current OCT-A are frequent particularly in pathologically altered maculae.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.