Which statement is true about typical ultrasound resolutions?

Which statement is true about typical ultrasound resolutions?

• A. Axial resolution is generally better than lateral.
• B. Lateral resolution is generally better than axial.
• C. They are always equal.
• D. Resolution is independent of frequency.

Answer: (A)

In ultrasound imaging, you’re looking at two main types of sharpness: axial resolution (along the beam) and lateral resolution (across the beam). Axial resolution is set by the spatial pulse length, which depends on the wavelength and how many cycles are in the pulse. Using higher frequency shortens the pulse and improves axial resolution, so you can separate structures that are close together along the beam direction. Lateral resolution relies on the width of the ultrasound beam across the image; the beam is typically narrow at the focal point but widens with depth, so lateral resolution tends to worsen as you image deeper, except right at the focus where it’s best. Because axial resolution is usually finer (smaller distance) than lateral resolution across most depths, the statement that axial resolution is generally better than lateral is true. The other options don’t fit: lateral isn’t always better, they aren’t always equal, and resolution does depend on frequency.

In ultrasound imaging, you’re looking at two main types of sharpness: axial resolution (along the beam) and lateral resolution (across the beam). Axial resolution is set by the spatial pulse length, which depends on the wavelength and how many cycles are in the pulse. Using higher frequency shortens the pulse and improves axial resolution, so you can separate structures that are close together along the beam direction. Lateral resolution relies on the width of the ultrasound beam across the image; the beam is typically narrow at the focal point but widens with depth, so lateral resolution tends to worsen as you image deeper, except right at the focus where it’s best. Because axial resolution is usually finer (smaller distance) than lateral resolution across most depths, the statement that axial resolution is generally better than lateral is true. The other options don’t fit: lateral isn’t always better, they aren’t always equal, and resolution does depend on frequency.