Knowra Ultrasonography Ultrasonography Ultrasonography uses high-frequency sound waves and their echoes to create images of structures inside the body, often in real time and without ionizing radiation.
Acoustic impedance : A measure of how strongly a material resists the propagation of sound, determined by its density and sound speed. Impedance differences at tissue boundaries create the echoes used to form images.
Obstetric ultrasonography : Ultrasound imaging used to assess pregnancy, the fetus, and related structures. It is a common application for monitoring fetal development without ionizing radiation.
Computed tomography : An imaging method that uses X-rays and computational reconstruction to create cross-sectional images. CT penetrates bone and air-filled regions more reliably, but uses ionizing radiation.
Ultrasound : Sound waves with frequencies above the upper limit of typical human hearing, about 20 kilohertz. Medical imaging uses a high-frequency portion of this broader sound-wave range.
Ultrasound speckle : A granular interference pattern in ultrasound images produced by echoes from many small scatterers. Speckle can obscure boundaries and complicate measurement, despite carrying tissue information.
Piezoelectric effect : The generation of electric charge by certain materials under mechanical stress, and mechanical vibration when an electric field is applied. Piezoelectric elements in transducers convert electrical pulses into sound and returning echoes into electrical signals.
Echocardiography : Ultrasound imaging of the heart and its motion, valves, and blood flow. It applies real-time imaging and Doppler methods to cardiac structure and function.
Magnetic resonance imaging : An imaging method that uses magnetic fields and radiofrequency signals to create detailed images of the body. MRI offers strong soft-tissue contrast without ultrasound’s dependence on acoustic access.
Sound wave : A traveling mechanical disturbance that carries energy through a medium. Ultrasound imaging depends on sound traveling through tissue and reflecting at boundaries.
Ultrasound elastography : An ultrasound technique that estimates tissue stiffness from tissue deformation or shear-wave behavior. It extends imaging beyond anatomy, but measurements and interpretation vary across methods.
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