Which imaging modality uses high frequency sound waves to create images by detecting echoes from internal organs?

• A. Ultrasound
• B. X-ray
• C. MRI
• D. CT scan

Answer: (A)

Ultrasound imaging uses high-frequency sound waves emitted by a transducer and creates images by detecting echoes that bounce back from internal structures. The echoes vary as waves encounter different tissues, so the machine maps the timing and strength of these reflections into real-time pictures. This method is especially good for soft tissues and organs, and it doesn’t use ionizing radiation, making it safe for pregnancy and pediatric patients; Doppler modes also let us assess blood flow.

X-ray and CT rely on ionizing radiation and differences in tissue density to create images, while MRI uses magnetic fields and radiofrequency energy to image proton properties. These approaches do not depend on echoes from internal organs in the same way ultrasound does.