Increasing transducer diameter improves which aspect of imaging in the far field?

Increasing transducer diameter improves which aspect of imaging in the far field?

• A. Axial resolution
• B. Lateral resolution
• C. Temporal resolution
• D. Contrast resolution

Answer: (B)

The key idea is that the transducer size shapes the ultrasound beam. A larger diameter acts like a bigger aperture, producing a narrower, more focused beam in the far field. With a thinner beam, echoes come back from a smaller lateral area, so two objects that are side by side can be distinguished more clearly. That improvement in separating side-by-side features is what we call better lateral resolution. Axial resolution depends on how short the transmitted pulses are (pulse length and bandwidth), not on aperture size. Temporal resolution relates to how fast you can acquire image lines (frame rate) and is not directly set by the transducer diameter. Contrast resolution is about distinguishing different echo intensities amid noise and system settings, not about the beam width.

The key idea is that the transducer size shapes the ultrasound beam. A larger diameter acts like a bigger aperture, producing a narrower, more focused beam in the far field. With a thinner beam, echoes come back from a smaller lateral area, so two objects that are side by side can be distinguished more clearly. That improvement in separating side-by-side features is what we call better lateral resolution.

Axial resolution depends on how short the transmitted pulses are (pulse length and bandwidth), not on aperture size. Temporal resolution relates to how fast you can acquire image lines (frame rate) and is not directly set by the transducer diameter. Contrast resolution is about distinguishing different echo intensities amid noise and system settings, not about the beam width.