Temporal Changes in Brain Light Scattering and Its Independent Variables Within 2 Days of Life

Area of Science:

• Neonatal Physiology
• Biomedical Optics
• Neuroimaging

Background:

• Reduced scattering coefficient (μs"), measured by time-resolved near-infrared spectroscopy (TR-NIRS), correlates with brain water diffusion, indicating potential as a bedside marker for cerebral microstructure.
• However, the physiological factors influencing μs" and its early changes after birth are not well understood.

Purpose of the Study:

• To investigate the clinical associations with cerebral μs" in healthy term newborn infants within the first 48 hours of life.
• To explore the early postnatal changes in μs" and its relationship with clinical variables.

Main Methods:

• Utilized time-resolved near-infrared spectroscopy (TR-NIRS) to measure cerebral μs" in 18 healthy term newborn infants at 6 and 36 hours postnatally.
• Employed generalized estimating equations to analyze associations between μs" and 14 clinical variables.

Main Results:

• Median μs" was 7.395 cm⁻¹ at 6 hours and 7.112 cm⁻¹ at 36 hours, with no significant difference between time points (p = 0.327).
• Male sex was associated with significantly higher μs" (regression coefficient = 0.895, p = 0.007).
• Caesarean delivery was associated with significantly lower μs" (regression coefficient = -0.969, p = 0.012), with a transient effect that diminished between 6 and 36 hours postnatally (difference = 0.057, p = 0.016).

Conclusions:

• Delivery mode transiently influences cerebral scattering properties in newborns.
• Sex is a stable determinant of cerebral scattering in the early postnatal period.
• TR-NIRS shows promise as an acute-phase cerebral monitoring tool in neonates, warranting further investigation.