Another name for axial resolution is?

• A. Transverse resolution
• B. Azimuthal resolution
• C. Angular resolution
• D. Range resolution

Answer: (D)

Axial resolution is about distinguishing two reflectors that lie along the path of the ultrasound beam, in the depth direction. It depends on how long the pulse is in tissue—the spatial pulse length (SPL). Shorter SPL means the echoes from two closely spaced objects can be separated more clearly. Range resolution is the distance along the beam axis that can be distinguished, and it is essentially the same concept as axial resolution. In other words, axial (range) resolution describes depth-based separation, while transverse (lateral) and angular terms describe separation across the beam or changes in beam direction. Since axial resolution concerns depth separation, the best term for it is range resolution.