Question

Diagnostic ultrasound is limited in its diagnostic application to the adult brain because:

A: The speed of sound in the brain is much faster than that in soft tissue resulting in a range artifact.
B: Nearly all of the sound is transmitted at the interface between bone and soft tissue with no reflection to create an image.
C: Diffraction of the sound beam occurs because of the irregular surface of the brain resulting in little transmission of sound through the cranial interface.
D: Bending of the sound beam due to refraction results in a multipath artifact that distorts the image making it non diagnostic at high frequencies.
E: The great acoustic impedance mismatch between the cranium and soft tissue causes most of the sound to be reflected at that interface.

Answer 1

Diagnostic ultrasound is not effective for adult brain imaging due to the significant acoustic impedance mismatch between the cranium and soft tissue, resulting in most of the sound being reflected.

Step-by-step explanation:

The question you've asked pertains to the limitations of diagnostic ultrasound when it comes to imaging the adult brain. The correct answer is E: The great acoustic impedance mismatch between the cranium and soft tissue causes most of the sound to be reflected at that interface. Unlike in other areas of the body where ultrasound can penetrate, the dense bone of the skull reflects most of the ultrasound waves. This reflection results in very little of the ultrasound actually passing through the bone to image the brain tissue, making ultrasound less useful for brain imaging compared to other imaging modalities such as CT or MRI that can penetrate bone.