10–14 October 2010, Prague, Czech Republic Short oral presentation abstracts artery bifurcation view and 3VT. Files were then reviewed by an expert examiner for quality of acquisition and correct identification of required structures. Results: 62 gravidae with singleton pregnancies between 20–32 weeks’ gestation were recruited for the study. After an initial learning curve of 10 exams trainees succeeded in identifying 95% of structures. STIC volumes were significantly better than cine-loop for displaying the required planes correctly. Conclusions: After an initial learning curve and under expert guidance, STIC is an excellent tool for trainees to master fetal echocardiography. OP22.06 Consistency of area measurements of the atrioventricular valve and the interventricular septum using STIC L. C. Rolo, P. M. Nowak , E. Araujo Junior, L. Nardozza, A. Moron S˜ ao Paulo Federal University, S ˜ ao Paulo, Brazil Objectives: The main objective of this study was to determine the intra-observer variability of the area measurements of the right atrioventricular valve and the interventricular septum using the technology of STIC (spatio-temporal image correlation). Methods: An observational cross-sectional study was performed involving 40 pregnant women between 18 and 33 weeks+6 of gestation. The area measurements of the right atrioventricular valve and the interventricular septum were performed using a Voluson 730 system. The offline analysis was performed using Voluson 4DView software. The tridimensional heart volume was acquired in the four chamber view with the apex in an anterior position. An offline analysis was performed later by a single observer (LCR) who obtained two area measurements of each atrioventricular valve and two area measurements of the interventricular septum (data were blinded). These measurements were performed manually in render mode. The intraclass correlation coefficient (ICC) and Bland-Altman graph were used to evaluate the intra-observer reliability. Results: There were no significant differences between intra-observer variability to the area measurements of the right atrioventricular valve and the interventricular septum using STIC. To the right atrioventricular valve, the ICC was 0.993 (IC 95% [0.987; 0.996]) with the mean difference of 0.987 cm 2 (P < 0.001). The Bland- Altman graph showed a mean difference of 0.01 (95% IC ±0.04 and SD: ±0.02) and the majority of the values was within the confidence interval (P < 0.05). To the interventricular septum, the ICC was 0.994 (IC 95% [0.988; 0.997]) and the mean difference of 0.991 cm 2 (P < 0.001). The Bland-Altman graph showed a mean difference of 0.01 (95% IC ±0.12 and SD: ±0.06) and the majority of the values was within the confidence interval (P < 0.05). Conclusions: Area measurements of the right atrioventricular valve and the interventricular septum using STIC from the 18 th to 33 th +6 week gestation were highly consistent. OP22.07 Nomogram of fetal atrioventricular valves area measured with STIC L. C. Rolo, P. M. Nowak , L. Nardozza, E. Araujo Junior, K. K. Haratz, A. Moron S˜ ao Paulo Federal University, S ˜ ao Paulo, Brazil Objectives: To establish normative data for the right atrioventricular valve area (RAVA) and left atrioventricular valve area (LAVA) between 18 and 33+6 weeks gestation using STIC (Spatio-Temporal Image Correlation). Methods: An observational cross-sectional study was performed involving 69 pregnant women between 18 and 33 weeks+6 gestation. The RAVA and LAVA measures were performed using a Voluson 730 ultrasound scanner (730 Expert version, GE), equipped with a 4–8-MHz transabdominal probe. The tridimensional heart volume was acquired in the four chamber view with the apex in an anterior position. Each valve area was drawn manually in render mode and the offline analysis was performed using Voluson 4DView software. To analyze the correlation between RAVA and gestational age (GA) and LAVA and GA, regression models were constructed and adjustments were made using the determination coefficient (r2), with 95% confidence interval. Results: There was a high correlation between measurements of the RAVA and GA (r = 0.80) and measurements of the LAVA and GA (r = 0.79). With the adjustments made, the best curve that demonstrated this correlation was an exponential curve: RAVA = exp (0.114 × GA + 0.026), r 2 = 0.69. There was a high correlation between LAVA and GA too (r = 0.79). The exponential model that best described the correlation was: LAVA = exp (0.119 × GA + 0.025), r 2 = 0.68. Mean RAVA increased from 0.20 cm 2 at 18 weeks to 0.95 cm 2 at 33+6 weeks. Mean LAVA increased too from 0.21 cm 2 at 18 weeks to 1.24 cm 2 at 33+6 weeks. Conclusions: The area measurements of fetal atrioventricular valves can be performed using STIC, and its values increase from 18 th to the 33 th +6 week of gestation. The atrioventricular valves area also showed a high correlation with GA. OP22.08 A quantitative study of the spatial angles among cardiac chambers and great vessels in the normal fetuses by spatiotemporal image correlation B. W. Zhao 1 , Z. Xie 2 1 Sir Run Run Shaw Hospital, Zhejiang University College of Medicine & Sir Run Run Shaw Institute of Clinical Medicine of Zhejiang University, Hangzhou, China; 2 Department of Diagnostic Ultrasound, Shaoxing Obstetrics and Gynecology Hospital, Shaoxing, China Objectives: To establish the reference ranges of the spatial angles among cardiac chambers and great vessels measured by spatiotemporal image correlation (STIC) in second and third trimester fetuses. Methods: Volume images of 352 normal fetuses from 20 to 38 weeks of gestation were recruited in the study. An off-line analysis of acquired volume datasets was carried out with multiplanar mode. Parameters measured included angles between: (1) the 4-chamber view and the left ventricular long axis view; (2) the left ventricular long axis view and main pulmonary artery; and (3) the ductal arch and aortic arch. The relationships between above-mentioned angles and gestational age were assessed by correlation and regression analysis. Results: The angle between the 4-chamber view and the left ventricular long axis view (range: 55.7 ◦ –35.7 ◦ , mean: 45.7 ◦ ± 5.12 ◦ ) was not correlated with gestational age (r = 0.03; P = 0.51). In contrast, the angle between the left ventricular long axis view and main pulmonary artery, and the angle between the ductal arch and aortic arch was correlated with gestational age (P < 0.001), and the correlation coefficients were −0.53 and 0.57 respectively. The best-fit exponential curve regression equation of the angle between the left ventricular long axis view and main pulmonary artery was: Y = 154−4.24X + 0.05X, and the angle between the ductal arch and aortic arch was: Y =−20.8 + 2.65X−0.37X. Conclusions: The angles among cardiac chambers and great arteries of fetuses from 20 to 38 weeks of gestation can be quantitatively measured by using STIC. The reference ranges provide a reliable quantitative standard to estimate the spatial relationships of the cardiac large arteries of fetuses, which may be clinically useful in prenatal screening congenital heart disease. Ultrasound in Obstetrics & Gynecology 2010; 36 (Suppl. 1): 52–167 117