How does a plaque ulceration appear on color Doppler imaging compared with grayscale?

• A. It often appears smoother on color Doppler than on grayscale
• B. It appears the same on both
• C. It appears rougher on color Doppler
• D. Color Doppler cannot visualize plaque

Answer: (A)

Color Doppler tends to smooth out fine surface details because the color encoding is superimposed on the grayscale image and uses lower spatial resolution. Grayscale (b-mode) shows the actual plaque surface with high detail, so irregularities and crater-like ulcerations appear more pronounced. With color Doppler, subtle surface irregularities are less conspicuous, so the ulceration can look smoother, unless there is flow entering the ulcer crater, which would show as a color jet within the defect indicating communication with the lumen. This combination makes the plaque appear smoother on color Doppler than on grayscale.