Clinical significance of B-scan averaging with SD-OCT.

Averaging multiple scans is a potential advantage of optical coherence tomography. The authors evaluate the qualitative benefits of B-scan averaging on the visualization of outer retinal structures. A retrospective analysis was performed on Cirrus OCT (Carl Zeiss Meditec, Dublin, CA) B-scans from 1 eye of 35 patients referred to the imaging unit who underwent three types of scan acquisitions: no averaging, 4× averaging, and 20× averaging. Masked assessment of quality was made using a qualitative scale of 0 (worst) to 3 according to the ability to identify structure, brightness, and continuity. Quality scores consistently improved with 4× averaging, but improved only slightly further with 20×. Averaging appeared to have a statistically significant beneficial effect for the assessment of the external limiting membrane and outer nuclear layer (P < .05), with no significant benefit for visualization of the retinal pigment epithelium and inner segment/outer segment junction. The benefits of oversampling or averaging B-scans for visualizing outer retinal substructures are apparent even when averaging relatively few frames. These findings may be helpful when designing acquisition protocols in clinical trials and clinical practice. Copyright 2012, SLACK Incorporated.