Detecting abnormal placental microvascular flow in maternal and fetal diseases based on flow-compensated and...

Area of Science:

• Medical Imaging
• Biophysics
• Obstetrics

Background:

• Intravoxel Incoherent Motion (IVIM) imaging is utilized for assessing placental microcirculatory function.
• Conventional IVIM parameters may not fully capture complex placental flow dynamics.

Purpose of the Study:

• To introduce and evaluate novel placental microcirculatory flow markers (f_b and v_b) derived from a joint analysis of flow-compensated (FC) and non-compensated (NC) diffusion MRI.
• To assess the diagnostic performance of these new markers in differentiating between normal pregnancies, gestational diabetes mellitus (GDM), and fetal growth restriction (FGR).

Main Methods:

• A joint FC-NC IVIM model was employed to estimate ballistic microcirculatory flow fraction (f_b) and velocity (v_b).
• Diffusion MRI scans were performed on pregnant individuals with GDM (n=15), FGR (n=12), and age-matched controls (n=19 for GDM, n=15 for FGR).
• Conventional IVIM indices and the new markers were compared across groups for the whole placenta and its maternal/fetal sides. A linear support vector machine (SVM) was used for classification.

Main Results:

• Significantly lower whole-placenta v_b was observed in both GDM (p=0.017) and FGR (p=0.043) compared to controls, with more pronounced differences on the fetal side.
• f_b and f_FC showed group differences on the fetal side, and D_FC differed in the whole placenta for GDM patients.
• v_b achieved the highest diagnostic accuracy (70.6% for GDM, 63.0% for FGR), with the combination of f_b and v_b improving accuracy to 73.5% (GDM) and 66.7% (FGR).

Conclusions:

• The ballistic microcirculatory flow velocity (v_b) demonstrates superior performance in diagnosing GDM and FGR.
• The joint FC-NC IVIM method holds significant potential for enhanced placental examinations and diagnosis of pregnancy-related disorders.