Which property does wavelength influence most directly in axial resolution?

Which property does wavelength influence most directly in axial resolution?

• A. Lateral resolution
• B. Frame rate
• C. Axial resolution
• D. Acoustic impedance

Answer: (C)

Axial resolution is governed by the spatial pulse length, which is the length of the ultrasound pulse along the beam. Spatial pulse length depends on the wavelength and how many cycles are in the pulse. Shorter wavelengths produce a shorter pulse length, so two reflectors that are close together along the beam can be distinguished more clearly. That direct link between wavelength and how finely we can separate points along the beam is why wavelength influences axial resolution most strongly. Lateral resolution, by contrast, relies on the beam width and focusing across the image, not the wavelength in the same direct way. Frame rate is about how fast you can acquire lines, tied to pulse repetition frequency and depth. Acoustic impedance affects reflection strength at boundaries, not how closely two points along the beam can be resolved.

Axial resolution is governed by the spatial pulse length, which is the length of the ultrasound pulse along the beam. Spatial pulse length depends on the wavelength and how many cycles are in the pulse. Shorter wavelengths produce a shorter pulse length, so two reflectors that are close together along the beam can be distinguished more clearly. That direct link between wavelength and how finely we can separate points along the beam is why wavelength influences axial resolution most strongly.

Lateral resolution, by contrast, relies on the beam width and focusing across the image, not the wavelength in the same direct way. Frame rate is about how fast you can acquire lines, tied to pulse repetition frequency and depth. Acoustic impedance affects reflection strength at boundaries, not how closely two points along the beam can be resolved.