Purpose:
To determine the effect of spectral domain optical coherence tomography (SDOCT) B-scan density on the qualitative assessment of structural changes in patients with neovascular age-related macular degeneration (AMD).
Methods:
Data were collected from 59 eyes, newly diagnosed with neovascular AMD, that underwent volume OCT imaging with 3D OCT-1000 (Topcon, Japan) using the 512 x 128 horizontal raster protocol. Raw OCT data were imported into the Doheny Image Reading Center (DIRC) OCT viewing and grading software, termed "3D-OCTOR." For each case, 3D-OCTOR was used to generate different B-scan subset densities: 1/16 (8 B-scans), 1/8 (16 B-scans), 1/4 (32 B-scans), 1/2 (64 B-scans). At each B-scan density, scans were assessed independently for the presence of intraretinal cystoid spaces, subretinal fluid (SRF), diffuse retinal thickening (DRT), subretinal tissue (SRT), and pigment epithelium detachment (PED). The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were then calculated and used to compare the efficacy of different B-scan densities in detecting each feature.
Results:
The sensitivity of detecting cysts, SRF, DRT, SRT, and PED all increased in a step wise fashion from 1/16 B-scan density readings to 1/2 B-scan density readings (Table). The largest increase in sensitivity was noted in the detection of SRT which was 64.7% (CI 50.1-77.6) in the 1/16 B-scan density group and 90.2% (CI 78.6-96.7) in the 1/2 B-scan density group. The smallest increase in sensitivity was noted in the detection of PED which was 86.4% (CI 75.0-94.0) in 1/16 B-scan density group to 96.6% (CI 88.3-99.6) in the 1/2 B-scan density group.
Conclusions:
When evaluating patients with neovascular AMD, increasing the B-scan density improves the sensitivity of spectral domain OCT for the detection of characteristic features of exudation often used to guide treatment decisions. Determination of the optimal B-scan density for the qualitative assessment of neovascular AMD may be of value for the design of SDOCT scanning protocols in clinical trials, as well as in clinical practice.
Keywords: age-related macular degeneration • imaging/image analysis: clinical • retina