Which statement best describes a typical disadvantage of a small-footprint ultrasound transducer?

Which statement best describes a typical disadvantage of a small-footprint ultrasound transducer?

• A. Resolution is degraded at large distances.
• B. It cannot be focused in the elevation direction.
• C. The field of view in the far field is only 1/4 the diameter of the transducer.
• D. The near-field lateral resolution is poor.

Answer: (A)

Small-footprint probes trade depth penetration for a more compact, maneuverable design. Because the aperture is small, the ultrasound beam diffracts and spreads more quickly as it travels. That beam widening directly reduces lateral resolution at greater depths, so the image becomes less sharp the farther you look. This is the typical drawback of a tiny footprint: good detail near the transducer, but degraded resolution at large distances. The other options describe limitations that aren’t inherent or universal for all small-footprint transducers—for example, focusing in elevation can be achieved with the right array design, the far-field field of view isn’t fixed to a simple fraction of the diameter, and near-field lateral resolution isn’t necessarily poor.

Small-footprint probes trade depth penetration for a more compact, maneuverable design. Because the aperture is small, the ultrasound beam diffracts and spreads more quickly as it travels. That beam widening directly reduces lateral resolution at greater depths, so the image becomes less sharp the farther you look. This is the typical drawback of a tiny footprint: good detail near the transducer, but degraded resolution at large distances. The other options describe limitations that aren’t inherent or universal for all small-footprint transducers—for example, focusing in elevation can be achieved with the right array design, the far-field field of view isn’t fixed to a simple fraction of the diameter, and near-field lateral resolution isn’t necessarily poor.