Question

You are scanning a large abdominal mass that is composed primarily of fat. Which of the following are you most likely to encounter?

A. Posterior acoustic shadowing caused by increased attenuation through the fat
B. Axial misregistration of the mass on the screen caused by the slower propagation speed through fat
C. Lateral misregistration of the mass on the screen because of refraction
D. Total reflection of the sound beam caused bya large acoustic impedance mismatch
E. Diffraction of the sound beam due to a virtual small aperture through the mass

Answer 1

When scanning a large abdominal mass composed primarily of fat, you are most likely to encounter posterior acoustic shadowing caused by increased attenuation through the fat.

Step-by-step explanation:

The reflection and transmission of ultrasound waves at the boundary between different media depend on the difference in acoustic impedance between the two media. Acoustic impedance is determined by the product of the density and the speed of sound in the medium.

In the case of a large abdominal mass composed primarily of fat, the ultrasound waves will encounter posterior acoustic shadowing caused by increased attenuation through the fat. This means that the sound waves will be absorbed and scattered more by the fat tissue, resulting in a shadow behind the mass on the ultrasound image.