I. Sarris

Systematic review of methodology used in ultrasound studies aimed at creating charts of fetal size.

Please cite this paper as: Ioannou C, Talbot K, Ohuma E, Sarris I, Villar J, Conde‐Agudelo A, Papageorghiou A. Systematic review of methodology used in ultrasound studies aimed at creating charts of fetal size. BJOG 2012;119:1425–1439.

A review of fetal volumetry: the need for standardization and definitions in measurement methodology

Volume charts of fetal organs and structures vary considerably among studies. This review identified 42 studies reporting normal volumes, namely for fetal brain (n = 3), cerebellum (n = 4), liver (n = 6), femur (n = 2), lungs (n = 15), kidneys (n = 3) and first‐trimester embryo (n = 9). The differences among median volumes were expressed both in percentage form and as standard deviation scores. Wide discrepancies in reported normal volumes make it extremely difficult to diagnose pathological organ growth reliably. Given its magnitude, this variation is likely to be due to inconsistencies in volumetric methodology, rather than population differences. Complicating factors include the absence of clearly defined anatomical landmarks for measurement; inadequate assessment and reporting of method repeatability; the inherent difficulty in validating fetal measurements in vivo against a reference standard; and a multitude of mutually incompatible three‐dimensional (3D) imaging formats and software measuring tools. An attempt to standardize these factors would improve intra‐ and inter‐researcher agreement concerning reported volumetric measures, would allow generalization of reference data across different populations and different ultrasound systems, and would allow quality assurance in 3D fetal biometry. Failure to ensure a quality control process may hamper the wide use of 3D ultrasound. Copyright

Surface area measurement using rendered three‐dimensional ultrasound imaging: an in‐vitro phantom study

Cranial sutures and fontanelles can be reliably demonstrated using three‐dimensional (3D) ultrasound with rendering. Our objective was to assess the repeatability and validity of fontanelle surface area measurement on rendered 3D images.

A longitudinal study of normal fetal femur volume

Fetal femur volume (FV) is a useful marker of skeletal growth. Our objective was to create a normal FV chart in a cohort of healthy pregnant women and to assess FV repeatability.

OP26.08: Automated standard plane selection from fetal abdominal ultrasound volumes using a machine learning algorithm

parameters and cortical maturation landmarks able to predict postnatal outcome in fetuses with borderline (VMBL) or moderate ventriculomegaly (MDVM). Methods: We retrospectively studied 34 fetuses with F-MRI diagnosis of VMBL or VMMD not resolved during pregnancy. Ultrasound (US) and/or F-MRI monitoring was performed for all fetuses, of which 6 fetuses with adverse postnatal outcome and 28 with favorable postnatal outcome. The sulcation, the superficial cortical gyration and the interopercular (IO) angles were visualized and correlated to the gestational age. The interopercular distance (IOD) antero-posterior (AP) and craniocaudal (CC) were measured and correlated to the normal value of corresponding gestational age. Results: In the group of fetuses with adverse postnatal outcome we observed: 2/6 fetuses with sulcation delay, 3/6 with superficial cortical gyration delay, 6/6 with enlarged IOD AP, 6/6 with increased IOD CC and 3/6 with IO angles delay. In the group of fetuses with favorable postnatal outcome we observed: 1/28 fetuses with sulcation delay, 2/28 with superficial cortical gyration delay, 2/28 with enlarged IOD AP, 1/28 with enlarged IOD CC and 3/28 with IO angles delay. Conclusions: Delayed development of sulcation, superficial cortical gyrarion, IO angles and increased biometric parameters of Sylvian fissure maturation IOD AP and IOD CC suggest a possible association with poor prognosis. F-MRI is able to detect these parameter objectively to provide a more appropriate counseling to pregnant women even at an early stage of pregnancy.

P28.02: Automated fetal biometry image landmark detection for confirming correct image planes: abdominal circumference

dimensional sagital view of the fetal front was performed to make the 3D reconstruction. Only one examiner obtained the anterior bâ by rendered mode. Correlation between gestational age (GA) and bâ was obtained by Pearson’s coefficient (r). Results: There was a weak linear correlation between GA and bâ (r = 0.05), however, between 18 and 24 weeks the bâ has ranged from 15.01 to 47.59 degrees. Percentiles from 5 to 95 are shown in table 1. The mean, median, SD, maximum and minimum values for each gestational age were calculated. Conclusions: Although no clear correlation between gestational age and angle values above the bregma, there are minimum and maximum values within the range 18–24 completed weeks of gestation. Such values may perhaps be adopted during the second trimester scan, seeking for early diagnosis of craniosynostosis. However, further studies are needed for more conclusive data.

P29.13: A simple method for calculation of the fetal femur volume in 3D ultrasound

C. Ioannou1, I. Sarris1, M. Yaqub2, R. Napolitano1, H. Nicholl3, J. A. Noble2, M. K. Javaid4, A. T. Papageorghiou1,5 1Nuffield Department of Obstetrics & Gynaecology, University of Oxford, Oxford, United Kingdom; 2Institute of Biomedical Engineering, University of Oxford, Oxford, United Kingdom; 3Department of Radiology, John Radcliffe Hospital, Oxford, United Kingdom; 4Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom; 5Oxford Maternal and Perinatal Health Institute, Green Templeton College, University of Oxford, Oxford, United Kingdom

OP20.09: The intra‐ and inter‐ observer variability in fetal measurements by ultrasound

to end-diastolic blood flow velocities (S/D) in the umbilical artery was measured in each patient. The patients were divided into 3 groups: the normal group with S/D ratios of less than 95thpercentile (n = 134), elevated S/D ratio group of 95thor more percentile (n = 60), and those with absent/reversed end diastolic flow (n = 62). Maternal characteristics and neonatal outcomes of these groups were comparatively analyzed. Results: The gestational age (GA) at the time of diagnosis of SGA, the mean GA at delivery, and the mean birth weight showed statistically significant difference among three groups (P < 0.001). Also, poor perinatal outcome was significantly increased in infants with abnormal S/D ratio (13.4% vs. 31.7% vs. 67.4%, P < 0.001). Multivariate logistic regression analysis revealed umbilical artery Doppler study as a significant independent factor for prediction of poor perinatal outcome (odds ratio: 3.7, 95% confidence interval 1.4–9.5, P = 0.007). Conclusions: Antenatal umbilical artery Doppler velocimetry is shown as a significantly efficient marker in predicting perinatal outcome in preterm SGA infants. We observed that poor umbilical artery Doppler index in preterm SGA pregnancies is associated with increased incidence of adverse perinatal outcome, and that umbilical artery Doppler index is an independent factor of prediction for perinatal outcome, irrespective of gestational age.

OP23.02: A pilot study of automated anatomical landmark detection for quality control purposes in the context of multicentre studies: abdominal circumference

Methods: Using 2D ultrasound, a duplicate set of standard fetal measurements (HC, AC, FL) were taken by an experienced operator. Following this 3D volumes from different predefined angles were also captured. These included predefined ‘‘suboptimal’’ volumes to assess whether these can lead to correct plane reconstruction. These were manipulated offline to recreate optimal 2D planes in order to assess (1) feasibility of reconstructing 2D planes; (2) accuracy and reproducibility of measurements; and (3) time taken to complete a full scan. Measurement differences were expressed as z scores. BlandAltman plots with limits of agreement were used for comparisons. Means and variances of measurements were compared using t-test and Levene’s test. Length of time to obtain 2D and 3D measurements were compared with Wilcoxon test. Results: Real time 2D measurements and 3D volumes were acquired in 65 fetuses at 14–41 weeks. Reconstructing 2D planes was not feasible in 7% for HC, 9% for AC and 11% for FL. Mean measurements between 2D and 3D were not statistically different (mean difference = − 0.05 z scores, 95% CI = − 0.13–0.04). However, the variance was statistically higher for 3D (P < 0.05). The median time required to perform a full fetal biometry scan (including offline analysis) was significantly higher for 3D than for 2D (3:04 mins vs. 1:57 mins, P < 0.001). Conclusions: Fetal biometry measurements using 3D volumes exhibit good agreement with real time 2D scanning with no significant mean difference. However, 3D-based examination took longer, not all volumes could be reconstructed and there was a higher variance.