In color Doppler imaging with linear arrays, which shape best describes the color Doppler portion of the image?

In color Doppler imaging with linear arrays, which shape best describes the color Doppler portion of the image?

• A. Rectangular
• B. Parallelogram
• C. Circular
• D. Elliptical

Answer: (B)

Color Doppler data are gathered along the parallel scan lines produced by a linear array. The region where velocity information is computed and displayed is defined by a block of those lines across a depth range, and when this block is mapped to the screen the edges follow the angled, line-based geometry rather than aligning with the screen’s horizontal and vertical axes. That slanted boundary on the top and bottom while the sides remain effectively parallel creates a four-sided figure with opposite sides parallel—a parallelogram. The other shapes would imply boundaries aligned strictly with the screen axes (rectangular) or boundaries defined by a radial symmetry (circular/elliptical), which isn’t how the color Doppler gating from a linear array is laid out.

Color Doppler data are gathered along the parallel scan lines produced by a linear array. The region where velocity information is computed and displayed is defined by a block of those lines across a depth range, and when this block is mapped to the screen the edges follow the angled, line-based geometry rather than aligning with the screen’s horizontal and vertical axes. That slanted boundary on the top and bottom while the sides remain effectively parallel creates a four-sided figure with opposite sides parallel—a parallelogram. The other shapes would imply boundaries aligned strictly with the screen axes (rectangular) or boundaries defined by a radial symmetry (circular/elliptical), which isn’t how the color Doppler gating from a linear array is laid out.