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

Abstract

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 (Adv Clin Exp Med 2015, 24, 3, 537-543).

Imaging and Imaging-Based Management of Pediatric Thyroid Nodules

“…Despite the increasing number of studies assessing the diagnostic value of elastography in adults, only a few of them focus on children with thyroid nodules, mainly due to specific problems concerning the use of the technique in the pediatric population, since the compressive nature of elastography induces discomfort in children [26]. Furthermore, the rarity of pediatric thyroid nodules in general causes a shortage in the study population needed to truly determine the importance of US elastography [34]. Notably, in a study by Rago et al, elastography could increase the accuracy of US in thyroid nodule differentiation regardless of the nodule size [35].…”

Ultrasound Elastography of the Neonatal Brain: Preliminary Study

“…In adults, clinical applications of elastography have included evaluation of nodules and masses in the breast and thyroid to predict malignancy, as harder lesions are more likely to be malignant . In pediatric patients, more accurate lesion and tissue natures in organs, including the liver, kidney, thyroid, and lymph nodes, can be derived by elastography . Among many organs, elastography of the liver is the most developed application in the pediatric population and is widely used to show liver fibrosis in nonalcoholic fatty liver disease or biliary atresia …”

“…5,6 In pediatric patients, more accurate lesion and tissue natures in organs, including the liver, kidney, thyroid, and lymph nodes, can be derived by elastography. 7,8 Among many organs, elastography of the liver is the most developed application in the pediatric population and is widely used to show liver fibrosis in nonalcoholic fatty liver disease 9 or biliary atresia. 10 For neonates, cranial sonography is one of the most effective tools available to diagnose brain disease.…”

Sonographic Evaluation of Pediatric Thyroid Nodules

“…A newly developed adjunct modality in the field of thyroid imaging is US elastography, which can be used to determine the stiffness or elasticity of the interrogated tissue, with increased stiffness represented by a larger value in kilopascals or shear wave velocity (Fig 22). Static US elastography analyzes tissue displacement caused by external compression to provide a real-time color map superimposed on a B-mode US image (61). US elastography was introduced to lessen the subjectivity of the clinical diagnosis of nodule firmness, which is associated with an increased risk of malignancy (62).…”

“…The use of US elastography in the pediatric population presents its own unique problems. The compressive nature of the technique induces discomfort when US elastography is used in children (61). Furthermore, the rarity of pediatric thyroid nodules in general causes a shortage in the study population needed to truly determine the importance of US elastography.…”