Which imaging modality uses high-frequency sound waves to visualize the heart?

• A. X-ray
• B. MRI
• C. Echocardiography
• D. CT

Answer: (C)

Ultrasound-based imaging of the heart relies on high-frequency sound waves. This approach, echocardiography, uses a transducer placed on the chest to emit sound waves and detect their echoes as they bounce off cardiac structures. The returning signals are transformed into real-time images that show the heart’s chambers, valves, and motion, and Doppler techniques can assess blood flow. Because it avoids ionizing radiation and provides immediate functional information, it’s especially useful for evaluating ejection fraction, valve disease, and congenital abnormalities. Other imaging modalities use different physical principles—X-ray and CT rely on ionizing radiation to create structural silhouettes, while MRI uses magnetic fields and radiofrequency to image soft tissues—so they don’t visualize the heart with sound waves.