How are M-mode displays created during ultrasound imaging?

How are M-mode displays created during ultrasound imaging?

• A. Echo amplitude is mapped to grayscale only
• B. The display uses color Doppler to encode motion
• C. Multiple 3D frames are combined
• D. Photo sensitive paper is moved at a constant speed across a B-mode display, and squiggly depth lines are drawn

Answer: (D)

M-mode displays depict motion by plotting echoes along a single ultrasound line over time. The transducer repeatedly sends along the same axial line, and for each pulse the echoes are recorded as a function of depth. As time passes, these depth profiles are recorded side by side, creating a motion trace. In older systems, this trace was produced by moving photo-sensitive paper at a constant speed across a display and drawing a squiggly line for the depth of reflected echoes, which visually shows how structures move toward or away from the transducer. This is different from turning echoes into a grayscale 2D image, using color Doppler to encode flow, or compiling multiple 3D frames.

M-mode displays depict motion by plotting echoes along a single ultrasound line over time. The transducer repeatedly sends along the same axial line, and for each pulse the echoes are recorded as a function of depth. As time passes, these depth profiles are recorded side by side, creating a motion trace. In older systems, this trace was produced by moving photo-sensitive paper at a constant speed across a display and drawing a squiggly line for the depth of reflected echoes, which visually shows how structures move toward or away from the transducer. This is different from turning echoes into a grayscale 2D image, using color Doppler to encode flow, or compiling multiple 3D frames.