What is axial resolution in ultrasound?

Axial resolution in ultrasound refers to the ability of the imaging system to distinguish between two structures that are close together in the direction of the ultrasound beam. This is primarily dependent on the spatial pulse length of the ultrasound waves. A shorter pulse length leads to better axial resolution, allowing for clearer differentiation of closely spaced structures.

The length of the ultrasound beam effectively determines how well the system can resolve details along the axis of the beam. Therefore, it is directly related to the ability to distinguish the echogenic features that lie along the direction of the sound wave propagation.

Other concepts like the width of the ultrasound slice and measurements that pertain to the image quality in the lateral dimension do not define axial resolution, and factors such as transmittance percentage relate more to the efficiency of the system rather than spatial resolution capabilities.