Which statement best describes what an A-scan provides in OCT?

Which statement best describes what an A-scan provides in OCT?

• A. Two-dimensional en face image
• B. Three-dimensional volume rendering
• C. Depth-resolved reflectivity along a single line
• D. Flow velocity in retinal vessels

Answer: (C)

Depth-resolved reflectivity along a single line is what an A-scan provides. In OCT, light travels into the tissue and the system records the backscattered signal as a function of depth along the optical axis. This yields a one-dimensional profile where each depth point corresponds to how strongly the tissue reflects light at that depth, revealing interfaces and microstructure along that line. If you move the beam laterally and collect many of these depth profiles, you build a cross-sectional image (a B-scan). Stacking multiple B-scans gives a 3D volume, and slicing at a fixed depth produces en face images. Measuring flow velocity requires Doppler or phase information, which goes beyond a single depth scan.

Depth-resolved reflectivity along a single line is what an A-scan provides. In OCT, light travels into the tissue and the system records the backscattered signal as a function of depth along the optical axis. This yields a one-dimensional profile where each depth point corresponds to how strongly the tissue reflects light at that depth, revealing interfaces and microstructure along that line. If you move the beam laterally and collect many of these depth profiles, you build a cross-sectional image (a B-scan). Stacking multiple B-scans gives a 3D volume, and slicing at a fixed depth produces en face images. Measuring flow velocity requires Doppler or phase information, which goes beyond a single depth scan.