The ability to distinguish similar structures with varying gray scale is termed

• A. Axial resolution
• B. Lateral resolution
• C. Temporal resolution
• D. Contrast resolution

Answer: (D)

Contrast resolution is about how well an imaging system can distinguish two adjacent structures that have similar brightness by differences in gray scale. When the system can display more gray levels and preserve subtle intensity differences, you can separate tissues that look alike because their echoes differ only slightly. This capability is what lets you pick out fine variations in tissue composition or pathology that a poorer gray-scale range would blur.

This is different from axial and lateral resolution, which describe the ability to separate two objects that are close in space along the beam direction or across the beam, and from temporal resolution, which concerns how quickly images or frames can be acquired to track motion.