inexpensive 3D-VR system for daily practice offering comparable depth perception and interaction. Methods: A desktop application was developed running on a.
9–12 September 2012, Copenhagen, Denmark
in each image plane. Planes with scores higher than an empirically determined threshold value were selected as standard planes by the AM. Two evaluation criteria were used to evaluate the performance of the AM: Positive Predictive Value = True Positive Planes/(True Positive Planes + False Positive Planes), and Sensitivity = True Positive Planes/(True Positive Planes + False Negative Planes). Results: The automated method showed accurate prediction of the manually labelled planes with an average sensitivity of 91.29% and a positive predictive value of 76.29%. Through closer inspection, all false positive planes selected by the automated method contained both the SB and UV in the correct position but had not been selected by the expert because of stricter criteria imposed. Conclusions: Our results show that machine learning can be used to automatically select a correct AC plane from a fetal 3D volume, and is an early first step in the direction of automated fetalsonography. Such an automated method has the potential for reducing the time needed to complete an ultrasound examination or to perform offline examinations. Further work will be needed to evaluate this and to extend it to other areas of fetal biometry.
OP26.09 A desktop 3D virtual reality system developed for virtual embyoscopy in routine daily ultrasound practice N. Exalto1 , A. H. Koning2 , P. J. van der Spek2 , E. Steegers1 1
Obstetrics and Gynaecology, Erasmus MC, Rotterdam, Rotterdam, Netherlands; 2 Bioinformatics, Erasmus MC, Rotterdam, Rotterdam, Netherlands Objectives: Virtual Embryoscopy was developed using 3D ultrasound (3D US) datasets. A stereoscopic CAVE-like virtual reality (VR) projection system (Barco I-Space) was used to examine the datasets as a hologram. Dedicated V-Scope volume rendering software was developed for creating the hologram, which offers intuitive interaction, allowing rotation, magnification, cutting with a clip plane and length- and volume measurements. However, fully immersive VR systems are too expensive to allow implementation in daily clinical practise. The aim of this study was to develop a small and inexpensive 3D-VR system for daily practice offering comparable depth perception and interaction. Methods: A desktop application was developed running on a personal computer and a 3D stereoscopic monitor with passive polarizing glasses for depth perception. A 3D-tracking system and a six degrees-of-freedom mouse are used for interaction with the hologram, including measuring. The V-Scope software was adapted to run on this desktop set-up. Results: We tested the prototype in our ultrasound department for use in routine clinical 3D ultrasound. Cartesian volumes are stored on a central server and immediately become available as a hologram without further intervention. Interaction, tool use and measuring are intuitive and easy to learn. Conclusions: With the development of affordable desktop 3D-VR equipment an innovative new way of looking at 3D ultrasound volumes as a hologram becomes available for routine use in daily clinical practice.
OP26.10 Effect of deviation from the mid-sagittal plane on the measurement of fetal nuchal translucency (NT) using Volume NTTM program H. Cho1 , J. Kwon1 , Y. Kim1 , G. Son1 , Y. Park1 , K. Lee2 , S. Kim2 1
Division of Maternal and Fetal Medicine, Department of Obstetrics and Gynecology, Institute of Women’s Life Medical Science, Yonsei University College of Medicine, Yonsei University Health System, Seoul, Republic of Korea; 2 Samsung Medison Research and Development Center, Seoul, Republic of Korea
Ultrasound in Obstetrics & Gynecology 2012; 40 (Suppl. 1): 55–170
Short oral presentation abstracts
Objectives: To investigate whether deviation from the mid-sagittal plane affect NT measurements made by a Volume NTTM program. Methods: Total seventy-two pregnant women were enrolled into this study and evaluated for effect of angle deviation from midsagittal plane. NT measurements were performed using Volume NTTM program of Medison Accuvix V20 Prestige. For angle deviation study, fetal head was rotated at 10 degrees interval and 3D volume was obtained. Then Volume NTTM program was used to measure angle of deviation from mid-sagittal plane and NT value was calculated for each angles of deviation. To find if there are differences of NT values according to angle of deviation, mean difference was compared with paired t test and intraclass correlation coeffieicents (ICC) of 2D value and NT value was calculated. Results: Median maternal age was 32 years (26–42 years) and median gestational age was 12+0 weeks (11+0–13+6 weeks). Median CRL was 55.2 mm (39.0–77.9 mm) and median BMI was 20.8 kg/m2 (16.4–27.0 kg/m2 ). Mean fetal NT was 1.31 mm (±0.44 mm) using 2D, 1.32 mm (±0.46 mm) by a deviation of 0–10 degrees, 1.29 mm (±0.44 mm) by a deviation of 11–20 degrees, 1.28 mm (±0.44 mm) by a deviation of 21–30 degrees, 1.24 mm (±0.44 mm) by a deviation of 31–40 degrees, and 1.23 mm (±0.42 mm) for 41–50 degrees. Mean difference of NT measurement between 2D and deviation of 31–40 degrees was −0.08 mm (−0.13, −0.02, P < 0.01), −0.10 mm (−0.18, −0.03 P < 0.01) for 41–50 degrees. The ICC for NT measurement were 0.89 (0–10 degrees), 0.89 (11–20 degrees), 0.85 (21–30 degrees), 0.80 (31–40 degrees) and 0.79 (41–50 degrees) for 2D and each angle deviation, respectively. Conclusions: When measuring NT with Volume NTTM program, increasing deviation away from the mid-sagittal plane results in progressive underestimation of the fetal NT thickness. Volume NTTM program showed better correlation with 2D NT values when measured with fetal head deviation less than 30 degrees.
OP27: CIRCULATORY DYNAMICS IN CARDIOVASCULAR PATHOLOGIES OP27.01 Is the circulatory dynamics of fetuses with gastroschisis different from normal? G. Martillotti1 , I. Boucoiran1 , L. Morin1 , J. Fouron2 1
Obstetrics and Gynecology, CHU Sainte-Justine, Universit´e de Montreal, Montr´eal, QC, Canada; 2 Fetal Cardiology Unit, Pediatric Cardiology Service, Department of Pediatrics, CHU Sainte-Justine, Universit´e de Montreal, Montr´eal, QC, Canada
Objectives: Extra abdominal herniation of splanchnic territory seen in fetuses with gastroschisis (GS) could lead to a redistribution of fetal circulation. This study compares circulatory variables of fetuses with GS with normal references values. Methods: Doppler echocardiographic recordings of 51 fetuses with isolated GS from 19 to 35 weeks were retrospectively reviewed. Forty-eight examinations were performed in the second trimester and 17 in the third. Eleven patients had two examinations. Left (QLV) and right (QAV) ventricular outputs, pulsatility indices in the umbilical (UAPI), middle cerebral arteries (MCAPI) and ductus venosus (DVPI) and aortic isthmus flow velocity index (IFI) were compared to reference values controled for gestational ages. Results: UAPI (P = 0.02) were higher and QLV lower (P = 0.009) than the 50th percentile of normals during both the second and third trimester, while QAV were higher only during the second trimester (P < .001) and DVPI only during the third trimester (P = 0.05). Conclusions: Significant hemodynamic disturbances are observed in fetuses with GS. Further studies are needed to assess the mechanism and the prognostic value of those disturbances.
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