Axial resolution in ultrasound refers to the ability to discern two separate objects that are longitudinally adjacent to each other in the ultrasound image. Axial resolution is generally around four times better than lateral resolution.
Axial resolution is defined by the equation: axial resolution = ½ ⨉ spatial pulse length. The spatial pulse length is determined by the wavelength of the beam and the number of pulses.
Therefore, to achieve a higher axial resolution using the shortest spatial pulse length possible and fewer number of pulses is advised. However, by using a shorter spatial pulse length the penetration of the beam will be affected.
- 1. Jerrold T. Bushberg, John M. Boone. The Essential Physics of Medical Imaging. (2011) ISBN: 9780781780575