Ultrasonography is another term[aka: sonography] used to describe the practice of using ultrasound technology for diagnostic imaging. It is synonymous with sonography and signifies the process of capturing ultrasound images, regardless of the body part or condition being examined. Ultrasonography is widely utilized in various medical imaging specialties, including obstetrics and gynecology, cardiology, radiology, urology, and many others. It has proven to be particularly valuable in obstetric imaging, allowing healthcare providers to monitor the growth and development of a fetus during pregnancy.
Ultrasonography uses the reflections of high-frequency sound waves to construct an image of a body organ. These ultrasonic waves are generated by a quartz crystal and are reflected at the interface between different tissues. The transmission and reflection of these high-frequency waves are displayed with different types of ultrasound modes.
See also sonogram, sonography, ultrasound imaging.

(US) Ultrasound is very high frequency sound above about 20,000 Hertz. Any frequency above the capabilities of the human ear is referred to as ultrasound.
Diagnostic ultrasound imaging uses much higher frequencies, in the order of megahertz. The frequencies present in usual sonograms can be anywhere between 2 and 13 MHz. The sound beam produce a single focused arc-shaped sound wave from the sum of all the individual pulses emitted by the transducer.

See also Medical Imaging.

Ultrasound biomicroscopy utilizes high frequency (10 - 50 MHz) diagnostic ultrasound to examine living tissue at a microscopic level and allows to image the skin with extremely high resolution to a depth of 2-3 centimeters. Ultrasound biomicroscopy images provide detailed anatomical information that can lead to better and more accurate treatments and avoid a biopsy.
Ultrasound biomicroscopy improves also the spatial resolution of US images of the anterior segment of the eye. US biomicroscopy of the eye operates in the 50 MHz range with a possible axial resolution on the order of 30 μm. In this frequency range, tissue penetration of only approximately 5 mm is attainable. Both continuous wave Doppler and high-frequency pulsed Doppler can be used.

See also Ultrasound Imaging Procedures, A-Scan, B-Scan and C-Scan.

An echo is defined as the repetition of a sound by reflection of sound waves from a surface.
Echo types used in ultrasound imaging:
Specular echoes are created from relatively large, regularly shaped objects with smooth surfaces. Specular echoes are relatively intense and angle dependent.
Scattered echoes are created from relatively small, weakly reflective, irregularly shaped objects. Scattered echoes are less angle dependant and less intense.

See also Specular Echo, and Scattered Echo.

Ultrasound elastography is a specialized imaging technique that provides information about tissue elasticity or stiffness. It is used to assess the mechanical properties of tissues, helping to differentiate between normal and abnormal tissue conditions.
The basic principle behind ultrasound elastography involves the application of mechanical stress to the tissue and measuring its resulting deformation. This is typically achieved by using either external compression or shear waves generated by the ultrasound transducer.
There are two main types of ultrasound elastography:
Both strain elastography and shear wave elastography offer valuable insights into tissue characteristics and can assist in the diagnosis and characterization of various conditions. In clinical practice, ultrasound elastography is particularly useful for evaluating liver fibrosis, breast lesions, thyroid nodules, prostate abnormalities, and musculoskeletal conditions. By providing additional information about tissue stiffness, ultrasound elastography enhances the diagnostic capabilities of traditional ultrasound imaging. It allows for non-invasive assessment, improves the accuracy of tissue characterization, and aids in treatment planning and monitoring of various medical conditions.
See also Ultrasound Accessories and Supplies, Sonographer and Ultrasound Technology.