What is associated with a weakly attenuating structure?

Comprehensive and Detailed Explanation From Exact Extract:

A weakly attenuating structure allows ultrasound waves to pass through with minimal loss of energy. Because of this, structures located posterior to the weakly attenuating region appear brighter than expected — this is known as distal (posterior) enhancement. This artifact is most commonly observed when scanning fluid-filled structures such as cysts, the bladder, or the gallbladder.

Official sonography instrumentation reference states:

“When sound waves encounter a structure that attenuates sound minimally (low attenuation), more sound energy reaches deeper tissues. This results in increased echo amplitude from structures located distal to the weak attenuating structure, creating the appearance of distal enhancement.”

Therefore, the correct answer is D: Distal enhancement.

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