Resolution of two structures at different depths along the path of the sound beam is termed:

Resolution of two structures at different depths along the path of the sound beam is termed:

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

Answer: (A)

Axial resolution is the ability to distinguish two structures that lie along the direction of the sound beam, at different depths. This depends on the pulse length: the shorter the spatial pulse length, the closer two interfaces can be and still appear as separate echoes. Shorter pulses come from higher frequency and/or fewer cycles per pulse, which improves axial resolution but may reduce penetration. In practical terms, if two reflectors are closer together along the beam path than about half the spatial pulse length, they won’t be resolved as distinct. By comparison, lateral resolution looks at side-by-side separation across the beam, temporal resolution relates to how quickly frames are acquired, and contrast resolution concerns distinguishing tissues by differences in echogenicity.

Axial resolution is the ability to distinguish two structures that lie along the direction of the sound beam, at different depths. This depends on the pulse length: the shorter the spatial pulse length, the closer two interfaces can be and still appear as separate echoes. Shorter pulses come from higher frequency and/or fewer cycles per pulse, which improves axial resolution but may reduce penetration. In practical terms, if two reflectors are closer together along the beam path than about half the spatial pulse length, they won’t be resolved as distinct. By comparison, lateral resolution looks at side-by-side separation across the beam, temporal resolution relates to how quickly frames are acquired, and contrast resolution concerns distinguishing tissues by differences in echogenicity.