What does an A-scan measure?

What does an A-scan measure?

• A. Reflectivity to determine the location of items
• B. Color and texture
• C. Blood flow velocity
• D. Tissue perfusion

Answer: (A)

An A-scan measures how the tissue’s reflectivity changes with depth along a single axial line. It produces a depth profile of backscattered light, showing peaks where there are strong interfaces between different tissue layers. That makes it ideal for locating where boundaries lie inside the sample. It doesn’t capture color or texture, which are visual properties, and it doesn’t directly measure flow velocity or tissue perfusion—that requires Doppler or perfusion-related imaging. So the description “reflectivity to determine the location of interfaces” is what an A-scan provides.

An A-scan measures how the tissue’s reflectivity changes with depth along a single axial line. It produces a depth profile of backscattered light, showing peaks where there are strong interfaces between different tissue layers. That makes it ideal for locating where boundaries lie inside the sample. It doesn’t capture color or texture, which are visual properties, and it doesn’t directly measure flow velocity or tissue perfusion—that requires Doppler or perfusion-related imaging. So the description “reflectivity to determine the location of interfaces” is what an A-scan provides.