OP05.08: Novel placental evaluation using multimodal MRI

Perfusion MRI (Intravoxel Incoherent Motion (IVIM)) has been shown to be useful in assessing placental function [1]. We develop a novel three-compartment model that combines IVIM with T2 relaxometry to separate maternal and fetal perfusion. The model distinguishes rapidly moving fetal blood with high pseudo-diffusivity; slowly-moving or static maternal blood with high T2; and otherwise static tissue with low-diffusivity and low T2. Three 2nd trimester pregnancies were imaged at 1.5T. We obtained measurements of IVIM at 7 b-values, and T2 relaxometry at 9 echo times, repeated at 2 b-values (0 and 200s/mm2). Imaging time was 20 minutes. We used a non-rigid registration routine [2], and applied the novel three-compartment model which combines overlapping bi-exponential IVIM and multi-compartment T2 relaxometry components [3], to give the perfusion-fraction (f), pseudo-diffusivity (d*), tissue diffusivity (d) and static fluid volume (v). We also fit the standard IVIM model for comparison. Figure 1 compares histogram distributions of the standard IVIM model (orange) with the three-compartment model (blue). f, d* and d remain comparable between the two models. A significant volume fraction (ν) is seen for static/slowly moving fluid with the new model, which cannot be separated using standard IVIM which we tentatively assign to maternal blood. Supporting information can be found in the online version of this abstract Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.