217: Longitudinal assessment of placental tissue homogeneity in normal pregnancies using a novel ultrasound tool

Abstract

Pathologic studies suggest a change in placental tissue structure in complicated pregnancies. Intensity Analysis (IA) is a novel noninvasive technology that measures tissue homogeneity by analyzing the statistical value of the acquired echo signal amplitude within a certain region of interest (ROI). The measurement is compared to an estimated variance of normal or reference tissue. Normalized Local Variance [NLV], is quantified and displayed in color maps, representing distribution of intensities within the ROI. As IA-NLV increases, homogeneity of tissue decreases. To our knowledge, IA of placental tissue has not been measured longitudinally in normal pregnancies. Our objective was to longitudinally evaluate IA of placental tissue in normal pregnancies. Normal pregnant women with singletons were consented for serial US exams starting between 12 0/7 and 13 6/7 weeks. US was performed every 2 weeks until 16 weeks, then every 4 weeks until delivery. IA of placenta was longitudinally measured on sagittal section of the placenta at level of cord insertion. The average of 3 measurements per US examination was used for analysis. Women with BMI > 30 Kg/m2 at enrollment or who developed any maternal or fetal complication were excluded. Linear and polynomial models assessed for best fit of data. 54 women were included in this analysis. 8 US were performed per pregnancy. The change in longitudinal NLV of the IA throughout gestation is shown in Figure 1. Cubic polynomial model represented the best fit of NLV with gestational age. NLV increased with advancing gestation. Non-invasive assessment of placental tissue structure with IA is feasible. Our data show reduction in homogeneity of placental tissue with advancing gestation in normal pregnancies. This NLV nomogram can be used as a reference to assess placental tissue homogeneity in complicated pregnancies.