Relationship of early brain growth pattern measured by ultrasound with neurological outcome at two years of age in very low birth weight infants

Abstract

The purpose of this study is to define the impact of early brain growth trajectory in very low birth weight infants (VLBWI) on neurological prognosis at 2 years, assessed using sequential ultrasound (US) scans. This is a prospective cohort study with consecutive inclusion of VLBWI ≤ 32 weeks gestational age and ≤ 1500 g at birth. Total brain volume (TBV) was assessed using sequential 3D-US from birth to discharge. Prognosis at 2 years (corrected age) was assessed using the Bayley Scales of Infant and Toddler Development Third Edition. TBV showed slower growth with postmenstrual age (PMA) in those VLBWI who had an adverse cognitive prognosis compared to those with good cognitive prognosis (mean difference in TBV between prognostic groups from 4.56 cm³ at 28 weeks to 42.58 cm³ at 43 weeks) as well as in those with adverse language prognosis (mean difference in TBV from 2.21 cm³ at 28 weeks to 26.98 cm³ at 43 weeks) although other variables showed more impact than TBV on language prognosis (gestational age at birth, brain injury at term, and socioeconomic status). No association was found between TBV and motor prognosis. Brain growth rate was also significantly higher in those VLBWI who presented good cognitive scores (18.78 + (0.33 × (PMA-33)) cm³/week) compared to those with adverse cognitive outcome (13.73 + (0.64 × (PMA-33)) cm³/week). Conclusion: Early altered brain growth is associated with poor cognitive prognosis at 2 years of age. Using sequential US monitoring, we can detect early brain growth deviation in patients who will have adverse cognitive outcomes. What is known: • The prediction of neurodevelopmental outcome of VLBWI is mostly based on the presence of brain injury in US and structural magnetic resonance imaging (MRI) at term. • Some studies have related brain volume measured on MRI at term with neurodevelopment outcome. What is new: • VLBWI with adverse cognitive prognosis at two years of age present smaller brain volumes detectable by sequential US during NICU admission. • Brain volume can be estimated from 2D and 3D US and has prognostic value in VLBWI.

Keywords: Brain growth; Brain volume; Neurodevelopment; Preterm; Ultrasonography; Very low birth weight infants.