Diffusion-Derived Vessel Density Computed From a Simplified Intravoxel Incoherent Motion Imaging Protocol in Pregnancies Complicated by Early Preeclampsia: A Novel Biomarker of Placental Dysfunction.

Abstract

Early preeclampsia is associated with significant placental hypoperfusion. We explore the diagnostic value of placental diffusion-derived vessel density (DDVD), a biomarker derived from diffusion-weighted magnetic resonance imaging, which measures in vivo vessel microperfusion, in the differential diagnosis of normal and early preeclampsia pregnancies. This was a prospective study involving 29 controls and 17 singleton pregnancies affected by early preeclampsia. Nineteen pregnancies from 28 to 34 weeks of gestational age were included from the normal group for a comparison with the early preeclampsia group. Using a 3.0 T magnetic resonance imaging scanner, diffusion-weighted images were obtained with the diffusion weighting b values of 0, 20, and 40 s/mm2. DDVDmean was the mean of DDVDb0b20 and DDVDb0b40, while DDVDb0b20 and DDVDb0b40 refer to the diffusion-derived vessel density values computed from b=0 and 20 s/mm2 images, and from b=0 and 40 s/mm2 images, respectively. The correlation between DDVDmean and gestational age was examined using a linear regression model. The area under the curve of the DDVDmean for early preeclampsia pregnancies detection was calculated by the receiver operating characteristic analysis. As gestational age increased, DDVDmean linearly decreased. DDVDmean was significantly decreased in the early preeclampsia pregnancies compared with the normal pregnancies (52.72±46.73 versus 213.34±93.50 au/pixel; P<0.001). The area under the curve (DDVDmean) for discriminating between normal and early preeclampsia pregnancies regardless of fetal growth restriction was 0.954, and the area under the curve was 1.000 when early preeclampsia pregnancies without fetal growth restriction were excluded. DDVDmean, an in vivo vessel microperfusion measure, allowed total separation of normal and early preeclampsia pregnancies.