Point shear wave elastography (pSWE) using Acoustic Radiation Force Impulse (ARFI) imaging: a feasibility study and norm values for renal parenchymal stiffness in healthy children and adolescents.

Abstract

To evaluate the applicability of point shear wave elastography (pSWE) for measuring renal parenchymal stiffnessin healthy children and adolescents and to establish norm values for shear wave speed (SWS) using two ARFI methodsand ultrasound probes. We prospectively investigated 264 children (43.9% males). pSWE(Virtual TouchTM Quantification and Virtual TouchTM Imaging Quantification (VTQ and VTIQ; Siemens, Germany)) wasperformed in the renal cortex of 528 healthy kidneys using a 1-6 MHz convex and a 4-9 MHz linear ultrasound probe inventrolateral and dorsal examinations. Feasibility and reproducibility of pSWE measurements were evaluated. SWS valueswere analysed with regard to age, body dimensions, kidney volume and measuring depth. pSWE measurementswere successful in >95% of subjects using the low and in <60% using the high-frequency probe. Mean SWS values (m/s)differed by method and probe: 2.10±0.43 (VTQ1-6MHz, convex, ventrolateral), 2.30±0.37 (VTQ1-6MHz, convex, dorsal), 1.58±0.44 (VTQ4-9MHz, linear, dorsal) and 1.96±0.27 (VTIQ4-9MHz, linear, dorsal). SWS was positively correlated withage, weight and body height, but independent of sex, BMI, or kidney volume and depth. pSWE (VTQ) is afeasible method to evaluate renal parenchymal stiffness in children of all ages. SWS values are age and weight dependentand differ significantly between high- and low-frequency probes. High-frequency probes and VTIQ should only be used inchildren <10 years.