The _____ in an array is the number of active elements.

The _____ in an array is the number of active elements.

• A. Bandwidth
• B. Elevational resolution
• C. Focal zones
• D. Aperture

Answer: (D)

In an ultrasound array, aperture is the number of active elements that participate in transmitting and receiving the pulse. This group of active elements defines the effective aperture, which determines how wide or narrow the beam is and how well lateral details are resolved. Activating more elements creates a narrower beam and better lateral resolution, while using fewer elements broadens the beam and can degrade resolution. The other terms refer to different aspects: bandwidth is the range of frequencies the system can use, elevational resolution concerns the slice thickness in the elevational direction, and focal zones describe the depth region where the beam is most focused. Since the question asks for the term that describes the number of active elements, the correct term is aperture.

In an ultrasound array, aperture is the number of active elements that participate in transmitting and receiving the pulse. This group of active elements defines the effective aperture, which determines how wide or narrow the beam is and how well lateral details are resolved. Activating more elements creates a narrower beam and better lateral resolution, while using fewer elements broadens the beam and can degrade resolution. The other terms refer to different aspects: bandwidth is the range of frequencies the system can use, elevational resolution concerns the slice thickness in the elevational direction, and focal zones describe the depth region where the beam is most focused. Since the question asks for the term that describes the number of active elements, the correct term is aperture.