EP22.09: Handheld ultrasound device: transverse section of uterus as a plane of choice for postpartum period

Abstract

Objectives: The aim of the study was to compare associations between blood flow volumes measured by the PixelFlux-Technique with measurements from time-averaged maximum velocity (TAmax). Methods: We conducted a prospective cohort study in 47 women with single pregnancies in week 24. Blood flow volume (ml/minute) in the uterine arteries was first calculated as 0.5*TAmax * cross section area of the vessel (cm 2 ) * 60. CSA was calculated as π * (diameter/2) 2 assuming that the uterine vessels were circular. Thereafter the blood flow was calculated using the PixelFlux method. PixelFlux is a new method based on pixelwise calculation of spatially angle-corrected velocities and areas of all pixels inside a vessel. Velocity is coded by colour, and by comparing the colour of each pixel in the cross-sectional area with the preset colour bar, it is possible to measure blood flow velocities directly. Then, all pixels' flow volumes inside a vessels section are added to calculate the flow volume of the vessel during a heart cycle. Figure 1 illustrates a uterine artery in the systole and the diastole. All the calculations and measurements are done automatically by the PixelFlux program. Results: The mean flow calculated from PixelFlux was 811ml/minute vs. 777ml calculated from TAmax. The mean difference was 24 ml/minute (95% CI -45; 94 ml/minute) and we did not observe any significant difference between the two methods due to the fact that the CI intervals were crossing zero. The intra class correlation coefficient was 0.83 (95% CI 0.72-0.90) and limits of agreement were -441 ml/minute to 489 ml/minute. Conclusions: The PixelFlux method might be an easy and promising tool in calculating blood flow volumes in the uterine arteries directly.Supporting information can be found in the online version of this abstract Objectives: Microcephaly is one of the most common fetal structural abnormalities, and prenatal microcephaly is considered a group I malformation of cortical development diagnosed according to ultrasonographic (US) skull measurements. The purpose of this study is too evaluate the agreement between fetal head US and MRI biometric measurements of suspected microcephalic fetuses. Methods: This institutional review board-approved retrospective study with waived informed consent included 180 pregnant women and was conducted at our medical centre from March 2011 to April 2013. Biparietal and occipitofrontal diameter results of fetal head US normograms were compared to normograms for MRI. We used Pearson and Spearman rho non-parametric correlation coefficients to assess the association between two quantitative variables, paired t-test for paired quantitative variables, and McNemar test for paired qualitative variables. Results: The average biparietal diameter but not the average occipitofrontal diameter percentiles in fetal head US differed significantly from the MRI results (P < 0.0001). When looking at the accepted microcephaly threshold, both biparietal diameter and occipitofrontal diameter percentiles differed significant...