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.

2D ultrasound imaging is a widely used technique in medical imaging that provides two-dimensional visual representations of internal structures. A handheld device known as a probe or transducer contains piezoelectric crystals that emit and receive ultrasound waves which penetrate tissues and bounce back as echoes. The echoes are detected and converted into electrical signals. These signals are processed and displayed on a monitor, creating a real-time 2D grayscale image, with different shades of gray representing various tissue densities. The brighter areas on the image correspond to structures that reflect more ultrasound waves, while darker areas represent structures that reflect fewer waves or are attenuated by intervening tissues. The 2D-mode (or B-mode) provides cross-sectional views of the scanned area, showing a single plane or slice of the scanned area at a time.

Key Features and Uses of 2D Ultrasound:

Comparison with 3D and 4D Ultrasound:
See also Ultrasound Technology, Sonographer, Ultrasound Elastography, Obstetric and Gynecologic Ultrasound.

The prostate is a walnut-shaped gland surrounding the beginning of the urethra in front of the rectum and below the bladder. The prostate can become enlarged (particularly in men over age 50) and develop diseases like prostate cancer or inflammation (prostatitis). A large tumor can be felt by a rectal examination. The most effective way of detecting the early signs of prostate cancer is a combination of a prostate-specific antigen (PSA) blood test and a prostate ultrasound examination.
An abnormally high level of PSA can indicate prostate cancer or other prostate diseases such as benign prostatic hypertrophy or prostatitis. The transrectal sonography is an important diagnostic ultrasound procedure in determining whether there is any benign enlargement of the prostate or any abnormal nodules.
The imaging is performed with a rectal probe, yielding high resolution. High resolution 3D ultrasound provides reliable and accurate determination of the size and the location of cancer. Additionally, ultrasound elastography is a technique in development to improve the specificity and sensitivity of cancer detection. Ultrasound is also used to detect whether cancerous tissue is still only within the prostate or whether it has begun to spread out and to guide a diagnostic biopsy or ultrasound therapy.

See also Brachytherapy, and High Intensity Focused Ultrasound.

Shear Waves are waves that travel perpendicular to the direction of the sound beam. During an ultrasound examination, shear waves are generated and transmitted into the body using the ultrasound probe. These waves travel through the tissue and their speed of propagation is influenced by the tissue's stiffness. Softer tissues allow the shear waves to travel faster, while stiffer tissues slow them down.
By analyzing the speed of shear waves, ultrasound systems can provide quantitative measurements of tissue stiffness, known as shear wave elastography. This technique is particularly useful in assessing the stiffness of organs like the liver, breast, thyroid, and muscles.
Shear wave ultrasound elastography has various applications in clinical practice. For example, it can help identify liver fibrosis, a condition characterized by excessive scarring of the liver tissue. By measuring the liver's stiffness using shear waves, clinicians can assess the severity of fibrosis without the need for invasive procedures like liver biopsies.

The term 'sonogram' is often used interchangeably with 'ultrasound,' but it specifically refers to the resulting image or picture produced during a diagnostic ultrasound examination, also known as ultrasonography or sonography. It serves as a visual representation of the echoes detected by the transducer and provides detailed anatomical information about the area being examined. Sonograms are typically displayed on a monitor, printed on film, or stored digitally for further analysis and documentation by medical professionals such as sonographers and radiologists. They serve as invaluable diagnostic tools, aiding in the detection and evaluation of various medical conditions, as well as guiding interventions, ultrasound therapy, and treatment planning.
The term 'ultrasound' itself refers to the technology used during a sonogram, but it also finds several other applications beyond medical imaging. These include echolocation, crack detection, and cleaning, among others.
See also Ultrasound Imaging, Ultrasound Technology, Handheld Ultrasound, Ultrasound Accessories and Supplies, Environmental Protection and Ultrasound Elastography.