# Assessing Semiregional Cerebral Oxygen Consumption (CMRO2) in Preterm Neonates: A Quantitative MRI Cohort Study With Exploratory Analysis of Respiratory Support

## TL;DR

This study introduces a new MRI method to measure brain oxygen use in preterm infants and finds that noninvasive respiratory support may improve brain oxygenation.

## Contribution

A novel multimodal MRI technique is introduced for noninvasive assessment of cerebral oxygen consumption in preterm infants.

## Key findings

- CBF and CMRO2 were positively correlated with noninvasive respiratory support and negatively with room air exposure.
- Semiregional brain analysis revealed distinct impacts on different brain structures.
- The novel MRI method produced CBF and CMRO2 values consistent with existing literature.

## Abstract

Developing a noninvasive method for measuring oxygen consumption at both regional and whole‐brain levels in preterm infants is crucial for assessing brain development and neuronal injury in this vulnerable population. This study presents a multi‐modal MRI technique and analysis pipeline that produces whole‐brain semiregional maps—with the potential to be fully regional—which we employ in a cohort study to investigate how the duration of various respiratory supports in very preterm infants affects CBF and the cerebral metabolic rate of oxygen (CMRO2). Infants (n = 19) born < 32 weeks gestational age were recruited in the neonatal intensive care unit. Infants were scanned at term‐equivalent age using a 3 T MRI sequence comprising T1‐weighted, T2‐weighted, arterial spin labeling (ASL), and SWI. Days on three different categories of respiratory support, based on levels of invasiveness, were recorded. Using multiple linear regression, CBF and CMRO2 were analyzed against days on: respiratory support, days in room air, and the proportion of days on respiratory support; GA and PMA were used as confounding factors. Average CBF and CMRO2 of cortical grey matter was 14.3 ± 4.25 mL/100 g/min and 29.49 ± 29.49 μmol/100 g/min, respectively. CMRO2 and CBF were positively correlated with days on noninvasive respiratory support and negatively correlated with days in room air. Using our novel method, CBF and CMRO2 values aligned closely with literature values. Our exploratory findings suggest that the type of respiratory support may influence cerebral oxygenation during the neonatal period in infants born very preterm, with greater oxygen delivery and consumption associated with noninvasive respiratory support. Our semiregional brain analysis further highlights that different brain structures are impacted in distinct ways. This study presents a novel multimodal MRI approach to measure cerebral blood flow (CBF) and oxygen metabolism (CMRO2) in preterm infants. Exploratory findings suggest noninvasive respiratory support is associated with higher CBF and CMRO2, highlighting its potential impact on neonatal brain oxygenation and development.

This study presents a novel multimodal MRI approach to measure cerebral blood flow (CBF) and oxygen metabolism (CMRO2) in preterm infants. Exploratory findings suggest noninvasive respiratory support is associated with higher CBF and CMRO2, highlighting its potential impact on neonatal brain oxygenation and development.