Which change improves lateral resolution by narrowing the beam width?

Which change improves lateral resolution by narrowing the beam width?

• A. Increasing frame rate
• B. Increasing transducer aperture size
• C. Decreasing scan depth
• D. Increasing power

Answer: (B)

Lateral resolution improves when the ultrasound beam is narrower across the image plane, because a tighter beam can distinguish objects that are next to each other side-to-side. Increasing the transducer aperture size does this by allowing more elements to participate in transmitting and receiving. A larger aperture enhances focusing, producing a narrower beam at a given depth. With a thinner beam, echoes come from a smaller lateral region, so two adjacent structures appear more separated, improving lateral resolution. Other changes don’t directly narrow the beam. Increasing frame rate changes temporal resolution (how fast frames are displayed) but not the physical width of the beam. Decreasing scan depth or increasing power don’t narrow the beam width; they affect other aspects like the image range or penetration, not lateral resolution via beam narrowing.

Lateral resolution improves when the ultrasound beam is narrower across the image plane, because a tighter beam can distinguish objects that are next to each other side-to-side.

Increasing the transducer aperture size does this by allowing more elements to participate in transmitting and receiving. A larger aperture enhances focusing, producing a narrower beam at a given depth. With a thinner beam, echoes come from a smaller lateral region, so two adjacent structures appear more separated, improving lateral resolution.

Other changes don’t directly narrow the beam. Increasing frame rate changes temporal resolution (how fast frames are displayed) but not the physical width of the beam. Decreasing scan depth or increasing power don’t narrow the beam width; they affect other aspects like the image range or penetration, not lateral resolution via beam narrowing.