Dense B-Scan Optical Coherence Tomography Angiography

Purpose To describe a novel imaging technique, which we call "dense B-scan optical coherence tomography angiography" (DB OCTA), in which thin dense raster scans are used to produce highly resolved structural B-scans with superimposed flow signal that provide precise correlation between retinal microstructure and blood flow. Design Observational case series. Methods Normal eyes and eyes with macular findings of interest were imaged with DB OCTA in which 150-400 OCT B-scans were acquired within a narrow area (from a single line to 1 degree) with a width of 10-30 degrees. B-scans containing 5-7 consecutive frames were processed for OCTA signal and then combined and visualized post-acquisition by application of a Gaussian filter across neighboring scans. The result was a single, smoothed, high-resolution image that contained both structural and flow information. Tracked follow-up DB OCTA was used to detect subtle changes in pathology over time. Results Two hundred and thirty-seven eyes from 205 subjects aged 18-100 years (mean 72.88 ± 14.74 years) with a diverse range of macular findings were imaged with DB OCTA. Highly resolved scans showing precise localization of flow signal were readily obtained, even in patients with poor visual acuity and/or poor fixation. We present clinical examples that demonstrate the utility of DB OCTA for visualizing the associations between retinal microstructure and blood flow. Conclusions DB OCTA enables precise correlation between retinal microstructure and blood flow. The ability to obtain accurately aligned follow-up DB OCTA studies has the potential to refine the understanding and clinical management of a wide range of macular diseases.