18th World Congress on Ultrasound in Obstetrics and Gynecology Oral communication abstracts After vaginal delivery without avulsion changes were much less pronounced. Conclusions: It seems that changes in hiatal dimensions after childbirth are largely mediated by levator trauma. Traumatic hyperdistension seems to be relatively uncommon, with hiatal dimensions showing only relatively minor changes after vaginal delivery-unless there was overt trauma in the form of avulsion injury. This implies that excessive hiatal distensibility without trauma is likely congenital or acquired during pregnancy. OC004 Fetal cardiac output determination by four-dimensional fetal echocardiography using spatiotemporal image correlation (STIC) and VOCAL TM N. Hamill 1 , R. Romero 2 , S. A. Myers 3 , J. P. Kusanovic 2 , P. Mittal 1 , A. Carletti 2 , T. Chaiworapongsa 1 , E. Vaisbuch 2 , J. Espinoza 2 , F. Gotsch 2 , W. Lee 4 , L. Goncalves 2 , S. Hassan 1 1 Department of Obstetrics and Gynecology, Wayne State University, Detroit, MI, United States, 2 Perinatology Research Branch, NICHD, NIH, DHHS, Detroit, MI, United States, 3 Case-Metrohealth, Cleveland, OH, United States, 4 William Beaumont Hosptial, Royal Oak, MI, United States Objectives: The objective of this study was to determine fetal cardiac output (CO) using STIC and Virtual Organ Computed-aided Analysis (VOCAL TM ) from datasets acquired with four-dimensional (4D) ultrasound. Methods: This cross-sectional study included volume-datasets from fetuses between 19 and 39 weeks. Inclusion criteria were uncomplicated pregnancy with term delivery and birthweight adequate for gestational age (GA). Cardiac datasets, obtained with STIC, were reviewed and VOCAL TM was used to obtain volume estimates the left (LV) and right (RV) ventricles. Volumes were collected in both systole and diastole. Left and right ventricular stroke volumes were calculated and used to compute CO in ml/min. CO was also expressed as a function of estimated fetal weight (EFW) in ml/min/kg. Results were grouped according to gestational age quartiles (19–24, 25–28, 29–32, 33–39 weeks). Intra- and interobserver variability were assessed by 2 operators in 10 normal fetuses. Results: 102 fetuses were evaluated between 19 and 39 weeks (Mean: 28.5 weeks); 1) LV and RV CO (ml/min) increased with gestational age (GA) (LV CO: Spearman rho (r s ) = 0.8, P < 0.001; RV CO: r s = 0.8, P < 0.001); 2) however, the CO expressed as a function of EFW (ml/min/kg) did not change with advancing GA (LV CO: r s =-0.06, P = 0.5; RV CO: r s =-0.03, P = 0.8); and 3) intra- and interobserver coefficients of variation were 2.3% and 4.0%, respectively. Gestational age (weeks) Left Ventricle (LV) CO (ml/min) LV CO (ml/min/kg) Right Ventricle (RV) CO (ml/min) RV CO (ml/min/kg) 19–24 (n = 26) 47 +/- 12 98 +/- 21 46 +/- 11 96 +/- 19 25–28 (n = 26) 81 +/- 22 89 +/- 25 97 +/- 16 96 +/- 16 29–32 (n = 25) 133 +/- 28 89 +/- 17 126 +/- 35 84 +/- 22 33–39 (n = 25) 210 +/- 39 85 +/- 16 236 +/- 41 95 +/- 14 Conclusions: 1) Fetal cardiac output can be reproducibly estimated with 4D ultrasound using STIC and VOCAL TM ; 2) the left and right ventricular cardiac output (ml/min) increased with gestational age; however, such a change disappeared when cardiac output was adjusted for estimated fetal weight (ml/min/kg); and 3) the reference values reported herein can be used to assess cardiac function in pathologic conditions and study cardiovascular function of the human fetus. OC005 Ultrasound bioeffects: Quantification of cellular damage in animal fetal liver after use of Doppler pulse to measure ductus venosus B. Pellicer 1 , S. Herraiz 2 , T. S. Russell 3 , A. Montllor 4 , V. Felipo 5 , C. Simon 6 , A. Pellicer 7 1 Obstetrics and Gynecology Department, Prenatal Diagnosis Unit, Dr Peset Hospital, Valencia, Spain, 2 Fundacion IVI, Instituto Universitario IVI, University of Valencia, Valencia, Spain, 3 Instituto Universitario IVI, University of Valencia, Valencia, Spain, 4 Obstetrics and Gynecology Department, Dr Peset Hopsital, Valencia, Spain, 5 Neurobiology laboratory, Centro de Investigacion Principe Felipe, Valencia, Spain, 6 Stem cell Bank, Centro de Investigacion Principe Felipe, Valencia, Spain, 7 Obstetrics and Gynecology Department and Fundacion, Dr Peset Hospital and CIPF, Valencia, Spain Background: Doppler pulse is widely used despite little training in its safety. Screening markers have led earlier in gestation and higher frequencies to evaluate the embryos’ hemodynamics (ductus venosus, tricuspid regurgitation). Fetal cells are more sensitive to sound waves than adult cells. Animal studies have demonstrated that high doses delay neural migration and result in intestinal cellular damage in embryos. Objectives: This study aims to evaluate whether third trimester exposure of the ductus venosus (DV) to Doppler pulse waves augments apoptotic events in the rat fetal liver. Materials and Methods: On day 17 of pregnancy, the anterior abdominal surface of anaesthetised pregnant Wistar rats was shaved and exposed to ultrasound. An 13 MHz linear array transducer (13 MHz probe GE Medical Systems’ VIVID 7 PRO BT04) was manually swept over right uterine horn focusing on for 10 minutes on each of the ductus venosus of foetuses (n = 17). The pulse repetitive frequency was 5.8 kHz. Foetuses from the left horn were the non-exposed control group (n = 20). After 5 – 6 hours the uteri was removed and fetal livers were collected and ran on western blots for cleaved caspase-3 and normalized to β-actin. Results: Significant increase of apoptosis in experimental liv- ers: apoptotic events increased between 6 and 8 times that of unexposed controls. (P = 0.0030 and 0.0076 respec- tively). Conclusions: Rat fetal livers submitted to Doppler pulse waves show increased cellular damage compared to controls. The length and weight of the rat embryos from day 18 are approximately the size of a human embryo of 8–9 weeks. These data demonstrate the need to quantify the maximum exposure time for safely work within the field of diagnostic prenatal screening and animal models should be used to investigate the effects of exposure at differing gestational ages of development. OC006 Should uterine artery Doppler be taken into account in interpreting low PAPP-A values in the first-trimester screening for chromosomal defects? A. Galindo 1 , I. Herraiz 2 , E. A. Lopez 3 , J. Arbues 1 , A. Gra ˜ neras 1 , E. G ´ omez 2 , P. Manosalvas 2 1 Department of Obstetrics and Gynecology, Ultrasound and Fetal Pathophysiology Unit, Hospital Universitario ‘12 de Octubre’, Madrid, Spain, 2 Department of Obstetrics and Gynecology, Hospital Universitario ‘12 de Octubre’, Madrid, Spain, 3 Department of Clinical Biochemistry, Hospital Universitario ‘12 de Octubre’, Madrid, Spain Objectives: Maternal serum levels of pregnancy-associated plasma protein A (PAPP-A) are associated to both increased risk of aneuploidies and impaired trophoblast invasion. On the other hand, high resistences in uterine arteries (UtA) demonstrated 244 Ultrasound in Obstetrics & Gynecology 2008; 32: 243–307 View publication stats View publication stats