In utero diffusion MRI: challenges, advances, and applications

TL;DR

This paper reviews the challenges and recent advances in in utero diffusion MRI, emphasizing its applications in fetal brain and placental development, and discusses strategies to overcome environmental and technical obstacles.

Contribution

It provides a comprehensive overview of the specific challenges in fetal diffusion MRI and highlights recent methodological advances and applications in fetal brain and placental research.

Findings

Major improvements in acquisition and processing techniques

Successful application in fetal brain connectomics

Insights into placental maturation processes

Abstract

In utero diffusion MRI provides unique opportunities to non-invasively study the microstructure of tissue during fetal development. A wide range of developmental processes, such as the growth of white matter tracts in the brain, the maturation of placental villous trees, or the fibres in the fetal heart remain to be studied and understood in detail. Advances in fetal interventions and surgery furthermore increase the need for ever more precise antenatal diagnosis from fetal MRI. However, the specific properties of the in utero environment, such as fetal and maternal motion, increased field-of-view, tissue interfaces and safety considerations, are significant challenges for most MRI techniques, and particularly for diffusion. Recent years have seen major improvements, driven by the development of bespoke techniques adapted to these specific challenges in both acquisition and processing. Fetal diffusion MRI, an emerging research tool, is now adding valuable novel information for both research and clinical questions. This paper will highlight specific challenges, outline strategies to target them, and discuss two main applications: fetal brain connectomics and placental maturation.