What type of imaging method uses echoes of sound waves to visualize structures?

The correct answer is ultrasound. This imaging method employs high-frequency sound waves that are emitted by a transducer, which then travel through the body. When these sound waves encounter different structures or tissues, they are reflected back as echoes. The ultrasound machine then interprets these echoes to create real-time images of the internal structures, such as organs or tissues.

Ultrasound is particularly valuable in medical settings because it is non-invasive, does not utilize ionizing radiation, and provides immediate feedback which can be essential for diagnosis and monitoring. The use of sound waves allows for safe visualization of soft tissues and is commonly used in various applications including prenatal imaging and diagnosing conditions related to the heart, abdomen, and vascular systems.

In contrast, other methods like pneumotachography measure airflow but do not provide visual images, while endoscopy involves direct visualization through a scope inserted into the body, and high-speed cameras capture rapid movements but are not used for deep tissue imaging. Each of these alternatives serves different purposes and provides different types of information.