Which statement best describes a limitation of M-mode scanning?

Which statement best describes a limitation of M-mode scanning?

• A. Information Is Obtained Along Only One Line Of Sight
• B. Motion Lateral To The Transducer Is Displayed
• C. The Two-Dimensional Shape Of A Structure Is Shown
• D. Color Doppler Is Shown

Answer: (D)

M-mode scanning provides motion information along a single scan line over time. It shows how echoes move only along that one line, so it gives a one-dimensional view of motion rather than a full image of the structure. Because of this, you can’t visualize the two-dimensional shape of a structure, and motion or anatomy that isn’t along the line of sight isn’t represented. In practice, you’d use B-mode imaging to see the shape and Doppler modes to assess flow. So the key limitation described is that information is obtained along only one line of sight.

M-mode scanning provides motion information along a single scan line over time. It shows how echoes move only along that one line, so it gives a one-dimensional view of motion rather than a full image of the structure. Because of this, you can’t visualize the two-dimensional shape of a structure, and motion or anatomy that isn’t along the line of sight isn’t represented. In practice, you’d use B-mode imaging to see the shape and Doppler modes to assess flow. So the key limitation described is that information is obtained along only one line of sight.