F Mauad Filho

Reliability and validity of tissue volume measurement by three-dimensional ultrasound: an experimental model

To determine the validity and the intra‐ and interobserver reliability of volume measurements of an endometrium‐like model using a three‐dimensional (3D) ultrasound rotational technique.

Reproducibility of first‐ and second‐trimester uterine artery pulsatility index measured by transvaginal and transabdominal ultrasound

To examine and compare the reproducibility of measurement of first‐ and second‐trimester uterine artery pulsatility index (UtA‐PI) using transabdominal (TAS) and transvaginal (TVS) ultrasound.

P01.08: Fetal umbilical and middle cerebral arteries during the 2nd and 3rd trimester in low risk pregnancies: intra- and inter-observer reliability and agreement

Objectives: To compare the accuracy and repeatability of the volume perfusion index (VPI), -a mathematical model for calculation of flow developed by our team-, with the current available indexes for threedimensional power Doppler quantification (VI,FI and VFI) in an experimental in-vitro study. Methods: A phantom of flow was designed by using a mechanical pump generating a pulsatile flow with known values and by using elastic artificial vessels and blood mimicking fluid. A set of three and four-dimensional power Doppler volumes was obtained at different flow settings. Three dimensional volumes were quantified by using the VOCAL software included in the machine’s software. Fourdimensional flow measurement was evaluated by using a previously validated algorithm. Repeatability was evaluated through the intraclass correlation coefficient (ICC)for single unpaired tests and the Bland-Altmann (B-A) plot. Accuracy was tested by comparing the actual values against the obtained indexes with a polynomial regression model. Results: Phantom design was successful in generating a pulsatilelike flow and volumes could be taken in 92% of cases. ICC (95% CI) was 0.34 (0.23–0.51) for VI; 0.41 (0.3–0.51) for FI and 0.56 (0.43–0.69) for VFI. For VPI, it was 0.69 (0.48–0.79). B-A plot showed an inter-observer variability (%) (95% CI) of 48 (23–76) for VI; 62 (33–68) for FI; 29 (21–48) for VFI and 22 (15–29) for VPI. r-value (95% CI) was 0.45 (0.33–0.49) for VI; 0.53 (0.38–0.6) for FI; 0.62 (0.51–0.79) and 0.83 (0.65–0.9) for VPI (P < 0.01). Conclusions: Volume Perfusion Index exhibits a more robust internal validity than the traditional three-dimensional power Doppler indexes and might reflect more accurately actual changes in flow.

P28.12: Fetal volume in the first gestational trimester by three‐dimensional ultrasonography: intra‐ and inter‐observer reliability and agreement

Objectives: To estimate and compare the spent time and the intra/inter-observer reliability and agreement from methods of measuring fetal head and trunk volume (FV) between 11w0d and 13w6d. Methods: 2 observers measured FV from fetuses with crownrump length (CRL) = 45–84 mm. FV was measured using 30◦ step rotation evaluating unmodified multiplanar view (UMV = just placing the fetal chest on the central point) delineating the fetus in any plane, and standardized multiplanar view (SMV = fetal sagittal plane should in A plan, head to the left, back lying down, with the central point just below fetal heart) delineating the fetus in both A (SMV-A = fetus rotated over its small axis) and C plane (SMV-C = fetus rotated over its long axis). We also evaluate whether reducing step rotation using 15◦ and 9◦ could improve reliability/agreement using only the method with the best results in the first part of the study. We used Kolmogorov-Smirnov; repeated measures ANOVA to assess systematic errors and time spent; intraclass correlation coefficient (ICC) to assess reliability; and limits of agreement (LoA) width to assess agreement. Results: 40 fetuses were examined. No systematic errors were observed. Reliability and agreement were better for SMV-C. Reducing step rotation didn’t improve the results (table 1). Less time was spent using UMV and larger rotation steps. Conclusions: SMV-C using 30◦ was the best method to assess FV.

OP37.04: Applying FMBV technique in three‐dimensional power Doppler indices when evaluating placenta: importance of PRF adjustment

Objectives: Fractional moving blood volume (FMBV) is the only method which can adjust for depth when power Doppler ultrasound (PDU) signals are obtained. The purpose of this study was to investigate the effect of tissue depth on perfusion indices obtained by 3D-PDU and FMBV. Methods: One hundred and eighty women with uncomplicated pregnancies between 24–28 weeks of gestation were examined. FMBV and vascular (VI), flow (FI) and vascular/flow (VFI) indices were studied. FMBV, VI and VFI were simultaneously evaluated in 3 structures located at different depths: cervix (n = 100, mean distance (MD) 23.1 mm, SD 5.1 mm), anterior placentas (n = 100, MD 32.2 mm, SD 5.7 mm) and posterior placentas (n = 80, MD 76.5 mm, SD 12 mm). Statistical analysis included an assessment of the correlation between the FMBV and 3D-PDU vascular indices. Results: The correlations between FMBV and VI and VFI were statistically significant in the cervix (VI: r = 0.83, VFI: r = 0.82; P < 0.001) and anterior placentas (VI: r = 0.72, VFI: r = 0.70; P < 0.001) but not in posterior placentas (VI: r = 0.29, VFI: r = 0.23; P = 0.07). There was no association between FMBV and FI in any structure. No differences in FMBV estimation were observed between anterior and posterior placentas (mean 22.8%, SD 8.5; mean 21.8%, SD 9.6, respectively; P = 0.2), whereas the VI and VFI were significantly reduced in posterior placentas (P < 0.02). Conclusions: 2D and 3D-PDU blood perfusion indices are strongly correlated when examining structures in close proximity to the ultrasound probe; however, when the structures are far from the ultrasound probe, 3D-PDU yields results that do not correlate with FMBV.