Ultrasound Elastography--Review of Techniques and Its Clinical Applications in Pediatrics--Part 1.

Sonoelastography is a novel technique that uses ultrasound waves to assess the elasticity of tissues noninvasively. It provides an ultrasound-based method to detect and display the relative stiffness of tissue. The main principle of sonoelastography is the measurement of tissue distortion in response to external compression. Changes in elasticity and tissue deformation elicited by compression are measured, processed and then shown in real time presentation with color-coded elastograms. One of the most important applications of sonoelastography is the evaluation of liver diseases, mainly liver fibrosis assessment and staging. Although in terms of definite diagnosis the liver biopsy still remains the golden standard, elastography seems to be a very inexpensive, repeatable and noninvasive method to evaluate most of liver conditions. The technique is also applicable in detection and differential diagnosis of focal lesions. It provides better imaging information and therefore more accurate evaluation of the lesions nature, e.g. in liver, lymphatic nodes or thyroid gland. Most of the applications mentioned above are well known and have been described in details in adults. Similarly, most of sonoelastographic studies are based on groups of adults. The purpose of this review article is to bring this technology closer to pediatric clinicians and to summarize some of its current clinical applications that are being pursued. In this part we focus on utility of elastography in liver assessment in pediatric patients.