Added Value of Supersonic Shear Imaging in the Diagnosis of White Matter Damage in Preterm Infants

Overview

Preterm birth and perinatal events related can interrupt microscopic maturation of the developing white matter leading to diffuse injury and subsequent neurocognitive impairments. Brain maturation can be studied using diffusion tensor imaging but is difficult to assess early after birth, repeatedly and at the bedside. Supersonic Shear wave Imaging (SSI) could be of interest in this clinical setting. This technique, already investigated in adults (breast, thyroid or liver fibrosis staging), has not been yet evaluated in neonates. Objective: To describe the feasibility and reproducibility of quantitative elasticity mapping in preterm infants and to correlate to gestational age. Methods: SSI is a quantitative stiffness imaging technique based on the combination of a remote palpation induced into tissues by the radiation force a focused ultrasonic beam and an ultrafast ultrasound imaging sequence. Such ultrafast frame rates permit to track in real time the displacements induced by the propagation of the resulting shear waves. For each pixel, the shear wave speed can be estimated locally and enables quantitative mapping of the local shear elasticity (characterizing the stiffness in kPa). In this study, we will use a new generation of ultrafast ultrasound scanners (Aixplorer®, Supersonic Imagine, Aix en Provence, France) with a linear L10-2 probe (256 elements, 6 MHz) in neonates born between 25 and 40 weeks' gestation (n=100). Three separate acquisitions will be obtained for each area of interest both on right and left sides and stiffness was measured using a unique ROI of 2.5 cm².

White matter damage occurs in 20% of preterm infants in industrialized countries. These lesions are difficult to evaluate by standard ultrasound. The quantitative elastography is a new medical imaging technique and potentially a diagnostic tool in brain lesions in preterm infants. Shear wave Imaging (SSI) could be of interest in this clinical setting. This technique, already investigated in adults (breast, thyroid or liver fibrosis staging), has not been yet evaluated in neonates.