Detecting abnormal placental microvascular flow in maternal and fetal diseases based on flow-compensated and non-compensated intravoxel incoherent motion imaging.

Introduction: Intravoxel Incoherent Motion (IVIM) imaging has been used to assess placental microcirculatory flows. We proposed a joint analysis of flow-compensated (FC) and non-compensated (NC) diffusion MRI to estimate the fraction and velocity of ballistic microcirculatory flow (f _b and v _b ), and evaluated the diagnostic performance of the new markers in maternal and fetal disorders.
Methods: Gestational diabetes mellitus (GDM, n = 15) pregnancies and fetal growth restriction (FGR, n = 12), along with gestational age matched normal controls (n = 19 for GDM and 15 for FGR) underwent FC and NC-encoded IVIM scans at 1.5 T. f _b and v _b obtained from a FC-NC joint model, along with the conventional IVIM indices, were compared between patient groups for whole-placenta and maternal/fetal sides of the placenta. A linear support vector machine (SVM) was used to classify the GDM, FGR and controls.
Results: v _b of whole-placenta were significantly lower in both GDM (p = 0.017) and FGR (p = 0.043), compared with their controls, and the differences were more evident in the fetal side (p = 0.010 for GDM and p = 0.042 for FGR). f _b and f _FC showed group differences in the fetal side and D _FC showed differences in whole-placenta for GDM patients. In the classification task, v _b showed the highest diagnostic accuracy of 70.6% for GDM and 63.0% for FGR, and the combination of f _b and v _b further improved the detection accuracy to 73.5% and 66.7% for GDM and FGR, respectively.
Discussion: v _b showed superior performance in the diagnosis of GDM and FGR, indicating the potential of the joint FC-NC IVIM method for placenta examinations.
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