The Ossicle and Ultrasound

Of all the materials in the body, water produces by far the least attenuation. This means that water is a very good conductor of ultrasound. Water within the body, such as that within cysts and the bladder, forms "windows" through which underlying images can be easily imaged. However, the lung and bones act as a shield against easy access by ultrasound to some parts of the body. Lung has a much higher attenuation rate than either air or soft tissue. This is because the small pockets of air in the alveoli are very effective in scattering ultrasound energy. (Any interface involving air as one of the components will be an impenetrable barrier for the ultrasound. For this reason, the transducer is carefully coupled to the skin via mineral oil or gel in a manner that will eliminate all air bubbles). Because of this, the normal lung structure is extremely difficult to penetrate with ultrasound. Compared to the soft tissues of the body, bone has a relatively high attenuation rate. Thus, bone shields some parts of the body from access by ultrasound.

An interface between air and some other substance, like tissue or water, strongly scatters ultrasound waves. Which of the following is NOT a consequence of this?

A. Images are sharper with higher ultrasound frequencies.
B. Lungs have high ultrasound attenuation rates.
C. Sound transducers should be carefully coupled to the skin via gel.
D. All of the above are consequences.

Not B or C

I believe the correct answer is A.

Statement A is true, but it has nothing to to with scattering effects. It is because higher frequencies produce more echoes per unit time which increases the image resolution.

B and C ARE consequences of scattering effects as explained in the question.

D is incorrect because A is not a consequence.