Shedding light on the neonatal brain: probing cerebral hemodynamics by diffuse optical spectroscopic methods

Parisa Farzam,Katherine Hagan,Erin M Buckley,Maria Angela Franceschini,Stefan A Carp,Pei-Yi Lin,Terrie Eleanor Inder,P Ellen Grant

doi:10.1038/s41598-017-15995-1

Abstract

Investigating the cerebral physiology of healthy term newborns’ brains is important for better understanding perinatal brain injuries, of which the most common etiologies are hypoxia and ischemia. Hence, cerebral blood flow and cerebral oxygenation are important biomarkers of brain health. In this study, we employed a hybrid diffuse optical system consisting of diffuse correlation spectroscopy (DCS) and frequency-domain near infrared spectroscopy (FDNIRS) to measure hemoglobin concentration, oxygen saturation, and indices of cerebral blood flow and metabolism. We measured 30 term infants to assess the optical and physiological characteristics of the healthy neonatal brain in the frontal, temporal, and parietal lobes. We observed higher metabolism in the right hemisphere compared to the left and a positive correlation between gestational age and the level of cerebral hemoglobin concentration, blood volume, and oxygen saturation. Moreover, we observed higher cerebral blood flow and lower oxygen saturation in females compared to males. The delayed maturation in males and the sexual dimorphism in cerebral hemodynamics may explain why males are more vulnerable to perinatal brain injuries than females.

Highlights

Investigating the cerebral physiology of healthy term newborns’ brains is important for better understanding perinatal brain injuries, of which the most common etiologies are hypoxia and ischemia
We applied a hybrid device consisting of a frequency-domain near-infrared spectroscopy (FDNIRS) for measurement of hemoglobin concentration and oxygen saturation[9] in tandem with diffuse correlation spectroscopy (DCS) for measurement of an index of cerebral blood flow (CBFi)[10,11,12]
Flow and oxygen saturation can provide information regarding an index of cerebral metabolic rate of oxygen (CMRO2i)[20,21], an important marker of brain health since the brain is metabolically one of the most active organs in the body and its energy supply is based on aerobic metabolism, indicating the importance of oxidative metabolism in the brain and its monitoring[22,23,24,25,26,27,28,29,30,31]

Summary

Introduction

Investigating the cerebral physiology of healthy term newborns’ brains is important for better understanding perinatal brain injuries, of which the most common etiologies are hypoxia and ischemia. We employed a hybrid diffuse optical system consisting of diffuse correlation spectroscopy (DCS) and frequency-domain near infrared spectroscopy (FDNIRS) to measure hemoglobin concentration, oxygen saturation, and indices of cerebral blood flow and metabolism. We applied a hybrid device consisting of a frequency-domain near-infrared spectroscopy (FDNIRS) for measurement of hemoglobin concentration and oxygen saturation[9] in tandem with diffuse correlation spectroscopy (DCS) for measurement of an index of cerebral blood flow (CBFi)[10,11,12]. We have observed that in healthy neonates, girls tend to have lower oxygen saturation and higher blood flow than boys These findings may be part of the reason for which newborn males are more vulnerable to white matter injury, hypoxic-ischemic encephalopathy, and cerebral palsy than newborn females[35,36,37]

Methods

Results

Conclusion