High-frequency ultrasound in the evaluation of cerebral intraventricular haemorrhage in preterm rabbit pups.

Cerebral intraventricular haemorrhage (IVH) is the most common cause of severe neurologic impairment following preterm birth in human infants. Ideally, an animal model for cerebral IVH should allow for reliable noninvasive evaluation of haemorrhagic extension and of subsequent development of posthaemorrhagic ventricular dilatation (PHVD). The aim of this study was to evaluate the use of high-frequency ultrasound (HFU) in premature rabbit pups with cerebral IVH induced by IP glycerol injection. Serial examinations using HFU enabled an accurate description of haemorrhagic extension and measurement of progressive PHVD over 72 h. The coefficient of variation for inter- and intraobserver variability in two measurements of ventricular size was less than 8.8% and 9.3%, respectively. Repeated ultrasound-guided intraventricular injection and sampling could be performed in vivo excluding requirement of stereotactic procedures and sedation. Application of HFU is a powerful tool for the evaluation of mechanisms involved in cerebral IVH and PHVD in the preterm rabbit pup model.