# Feasibility and Validity of Ultra‐Low‐Field MRI for Measurement of Regional Infant Brain Volumes in Structures Associated With Antenatal Maternal Anemia

## TL;DR

This study shows that ultra-low-field MRI can accurately measure infant brain volumes linked to maternal anemia, making it a viable tool in low-resource settings.

## Contribution

This is the first study to validate ultra-low-field MRI against high-field MRI for infant brain regions associated with antenatal maternal anemia.

## Key findings

- Strong agreement between 3T and 64mT MRI for intracranial volume and brain regions like the caudate nucleus, putamen, and corpus callosum.
- Improved correspondence between MRI systems was observed in older infants, especially for basal ganglia structures.
- Findings support the use of ULF MRI for pediatric neuroimaging in low- and middle-income countries.

## Abstract

The availability of ultra‐low‐field (ULF) magnetic resonance imaging (MRI) has the potential to improve neuroimaging accessibility in low‐resource settings. However, the utility of ULF MRI in detecting child brain changes associated with anemia is unknown. The aim of this study was to assess the comparability of 3T high‐field (HF) and 64mT ULF volumes in infants for brain regions associated with antenatal maternal anemia. This neuroimaging substudy is nested within Khula South Africa, a population‐based birth cohort. Pregnant women were enrolled antenatally and postnatally, and mother–child dyads (n = 394) were followed prospectively at approximately 3, 6, 12, and 18 months. A subgroup of infants was scanned on 3T and 64mT MRI systems across study visits and images were segmented using MiniMORPH. Correlations and concordance coefficients were used to cross‐validate HF and ULF infant brain volumes for the caudate nucleus, putamen, and corpus callosum. Seventy‐eight children (53.85% male) had paired HF (mean [SD] age = 9.64 [5.26] months) and ULF (mean [SD] age = 9.47 [5.32] months) datasets. Results indicated strong agreement between systems for intracranial volume (ICV; r = 0.96, ρ
ccc = 0.95) and brain regions of interest in anemia including the caudate nucleus (r = 0.89, ρ
ccc = 0.86), putamen (r = 0.97, ρ
ccc = 0.96) and corpus callosum (r = 0.87, ρ
ccc = 0.79). This cross‐validation study demonstrates excellent correspondence between 3T and 64mT volumes for infant brain regions implicated in antenatal maternal anemia. Findings validate the use of ULF MRI for pediatric neuroimaging on anemia in Africa.

This cross‐validation study is the first to compare high‐field (HF; 3T) and ultra‐low‐field (ULF; 64mT) volume estimates for infant brain regions previously found to be associated with antenatal maternal anemia within the first 2 years of life.Key findings of this research demonstrate linear associations and strong agreement between HF and ULF volume estimates for the caudate nucleus, putamen, and corpus callosum in infants between 3 and 18 months of age. Improved correspondence between HF and ULF MRI was observed in older infants, particularly for basal ganglia structures.These novel findings validate the use of ULF MRI for pediatric neuroimaging work on antenatal maternal anemia and other prevalent health priorities in low‐ and middle‐income countries (LMICs).

This cross‐validation study is the first to compare high‐field (HF; 3T) and ultra‐low‐field (ULF; 64mT) volume estimates for infant brain regions previously found to be associated with antenatal maternal anemia within the first 2 years of life.

Key findings of this research demonstrate linear associations and strong agreement between HF and ULF volume estimates for the caudate nucleus, putamen, and corpus callosum in infants between 3 and 18 months of age. Improved correspondence between HF and ULF MRI was observed in older infants, particularly for basal ganglia structures.

These novel findings validate the use of ULF MRI for pediatric neuroimaging work on antenatal maternal anemia and other prevalent health priorities in low‐ and middle‐income countries (LMICs).

This cross‐validation study assessed the comparability of high‐field (HF; 3T) and ultra‐low‐field (ULF; 64mT) volumes in infants for brain regions associated with antenatal maternal anemia. Key findings demonstrated strong agreement between HF and ULF volume estimates for the caudate nucleus, putamen, and corpus callosum in infants between 3 and 18 months of age.