In imaging, lower frequencies permit greater penetration, enabling visualization of which target?

• A. Large organs (liver)
• B. Superficial structures (breast tissue)
• C. Brain and spine MRI
• D. Gadolinium

Answer: (A)

Lower-frequency ultrasound waves travel farther through tissue with less attenuation, so they penetrate deeper and let you visualize deep, large organs. The liver sits deep in the abdomen, making it a classic target seen with these settings. In contrast, higher-frequency probes give crisper detail but don’t reach as deep, which is why superficial structures like breast tissue are better imaged with higher frequencies. Brain and spine imaging isn’t typically done with ultrasound at all; MRI is used there, and gadolinium is a contrast agent, not a tissue target viewed purely by penetration. So the choice reflecting deep, large organs such as the liver is best.