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.