Low-Field Combined Diffusion-Relaxation MRI for Mapping Placenta Structure and Function

Abstract

Purpose: Demonstrating quantitative multi-parametric mapping in the placenta with combined $T{2}^{\ast }$-diffusion MRI at low-field (0.55T).

Methods: We present 57 placental MRI scans performed on a commercially available 0.55T scanner. We acquired the images using a combined $T{2}^{\ast }$-diffusion technique scan that simultaneously acquires multiple diffusion preparations and echo times. We processed the data to produce quantitative $T{2}^{\ast }$ and diffusivity maps using a combined $T{2}^{\ast }$-ADC model. We compared the derived quantitative parameters across gestation in healthy controls and a cohort of clinical cases.

Results: Quantitative parameter maps closely resemble those from previous experiments at higher field strength, with similar trends in $T{2}^{\ast }$ and ADC against gestational age observed.

Conclusion: Combined $T{2}^{\ast }$-diffusion placental MRI is reliably achievable at 0.55T. The advantages of lower field strength - such as cost, ease of deployment, increased accessibility and patient comfort due to the wider bore, and increased $T{2}^{\ast }$ for larger dynamic ranges - can support the widespread roll out of placental MRI as an adjunct to ultrasound during pregnancy.