Which statement best describes axial resolution in imaging transducers?

• A. Unrelated to transducer type
• B. Worsened by higher bandwidth
• C. Improved axial resolution
• D. Only affected by lateral resolution

Answer: (C)

Axial resolution measures how well you can distinguish two reflectors that lie along the path of the sound beam. It hinges on the spatial pulse length, which is essentially how long the pulse is in tissue. A shorter spatial pulse length lets the system separate two closely spaced interfaces along the beam direction, so axial resolution improves. Shorter pulses come from a higher center frequency and fewer cycles per pulse, and wider bandwidth also helps by allowing a briefer pulse in time. That’s why the statement describing axial resolution as improved is the best fit. Conversely, saying it’s worsened by higher bandwidth isn’t correct, and axial resolution isn’t independent of the transducer type, nor is it solely determined by lateral resolution, which relates to beam width across the image.