Ultrasound elastography in children - nice to have for scientific studies or arrived in clinical routine?

Abstract

Ultrasound elastography (USE) is a modality that in addition to fundamental B-mode, Doppler, and contrast-enhanced sonography is suitable to make qualitative and quantitative statements about the stiffness of tissues. Introduced more than 20 years ago in adults, USE becomes now a diagnostic tool also in children. The aim of this paper is to describe current available techniques for USE in children. The significance for routine use in children is shown, and further interesting applications are reported.

Keywords: Acoustic radiation force impulse; Shear wave elastography; Transient elastography; Ultrasound elastography.

Fig. 1

Various methods of ultrasound elastography. All use the measurement of deformation in response to an applied stress or force given by compression or creation of a push pulse (RTE, real-time elastography; TE, transient elastography; ARFI, acoustic radiation force impulse; SWE, shear wave elastography; IQ, image quantification; ROI, region of interest; 2D, two dimensional; GE US, general electric ultrasound; Q, quantification)

Fig. 2

Four-month old male infant with hepatosplenomegaly and cholestasis. Following sonography and elastography biopsy indicated. The result showed Niemann-Pick disease type A associated with liver fibrosis and reduced synthetic capacity of the liver. A B-mode imaging of the liver in the midclavicular line corresponding to hepatomegaly (Sequoia, Siemens, 5C3 probe). B SWE measurement in the right liver lobe. Shear wave speed of 2.82 m/s is significantly increased and has to be assessed in terms of fibrosis (Sequoia, Siemens, 5C1 probe)

Fig. 3

A 15-year-old girl who suffered from nephroblastoma at the age of 12 years. Routine ultrasound control following successful therapy showed a lesion in the right-sided thyroid gland. Histology revealed papillary carcinoma of the thyroid gland, no metastases of the nephroblastoma. A B-mode image demonstrates an inhomogeneous hypoechogenic lesion with unsharp borders in the medial part of the right-sided gland (ZS3, Zonare, L14-5 probe). B Real-time elastography revealed signs of increased stiffness (blue color, black arrow) of the tumor corresponding to suspected malignancy (ZS3, Zonare, L14-5 probe). C B-mode image shows small hyperechogenic bright point with shadowing artefact as a sign of possible calcification (ZS3, Zonare, L20-5 probe)

Fig. 4

Ultrasound elastography in peripheral cervical lymph nodes. A Color Doppler image of a lymph node near the mandible in a 2-year-old male with periapical osteitis caused by caries profunda. There is strong hypervascularization without swelling (Sequoia, Siemens, L14-5 probe). B Same case with SWE showing shear wave velocity < 1 m/s (Sequoia, Siemens, L10-4 probe). C Color Doppler imaging of a new cervical lymph node in a 14-year-old male with history of Burkitt lymphoma. There was no vascularization detectable (Sequoia, Siemens, L14-5 probe). D Same lymph node with SWE showing shear wave velocity of 1.84 m/s corresponding with increased stiffness. Imaging and elastography are suspicious for relapse (Sequoia, Siemens, L10-4 probe)

Fig. 5

A 16-year-old male with stenosing ileitis in Crohn’s disease. Ultrasound in routine follow-up without acute problems or increasing clinical score. A B-mode image revealing increased bowel wall thickness (6.5 mm) (Sequoia, Siemens, L10-4 probe). B Power Doppler imaging without any pathological increase in vascularization (Sequoia, Siemens, L10-4 probe). C SWE with no pathological qualitative distribution in color scale (Sequoia, Siemens, L10-4 probe). D SWE using quantitative evaluation with three regions of interest within the submucosa of the small bowel (median 1.42, 1.66, 1.85 m/s) (Sequoia, Siemens, L10-4 probe) which is lower than published cutoff values for active inflammation [52]

Fig. 6

A 13-year-old boy with testicular adrenal rest tumor in adrenogenital syndrome. A B-mode image demonstrating hypoechogenic inhomogeneous lesion in the lateral aspect of the testes (Sequoia, Siemens, L18-5 probe). B Color Doppler mode showed hypervascularization of the tumor (Sequoia, Siemens, L18-5 probe). C SWE demonstrated increased stiffness within the pseudotumor compared to the surrounding physiological tissue (Sequoia, Siemens, L10-4 probe)