To assess the capacity of high and low doses of the antimitotic drug mitomycin to prevent laryngeal stenosis in an animal model. Methods: A prospective, randomized, double-blind, controlled study was carried out. End-to-end anastomosis was performed in 18 rabbits after tracheal annulus resection to produce inflammation. There were 3 treatment groups: topical saline (isotonic sodium chloride solution) and low-dose (0.2 mg/mL) and high-dose (0.5 mg/ mL) topical mitomycin. Results: A total of 107 procedures were performed: 54 surgical procedures, 35 fibrobronchoscopies, and 18 biopsies. The effect of mitomycin was dose related. In the high-dose mitomycin group, most rabbits progressed to stenosis with a percentage decrease in airway diameter that was significantly greater than in the other 2 groups (P Ͻ.001). The mean (SD) percentage of maximum stenosis in the high-dose group was 51%(22%). In the lowdose and saline groups, it was 18% (13%) and 16% (9%), respectively. No significant differences in tracheal stenosis between the low-dose mitomycin and saline groups were observed. Blinded histopathological analysis also showed no significant differences between the saline group and the low-dose mitomycin group. Compared with the other 2 groups, the high-dose mitomycin group had a significant increase in fibroproliferative tissue (P Ͻ.001). Conclusion: These results suggest that topical mitomycin is not effective for avoiding tracheal stenosis and may provoke the opposite effect if the dose is not carefully selected.

Electronic poster abstracts cases with partial absent ribs, seven cases with spine anomalies and five cases with cardiac anomalies. Karyotype and postnatal autopsy show that three cases are male and two are female. Conclusions: 3D skeletal ultrasound mode imaging compare favourably with 3D spiral CT. Incorporation of 3D skeletal ultrasound mode imaging could provide a diagnostic feature that could assist in the prenatal diagnosis of sirenomelia. P23.11Prenatal diagnosis of small bowel obstruction with ultrasonography and MRI Objectives: To evaluate the value of ultrasonography and magnetic resonance imaging in the diagnosis of fetal small bowel obsrtuction. Methods: 14 fetus with ''double bubble'' sign or dilated small bowel were included in this study. MRI was used to analyze the location of the obstruction and the visibility of the colon and rectum. The final diagnosis was based on postnatal or fetal pathological examination. Results: With ultrasonography, 6 fetus showed classic ''double bubble'' sign, and the other 8 fetus showed vary degrees of dilated small bowel. 10 of them were associated with polyhydramnions, while 4 of them were associated with normal amniotic fluid volume. With MR, the ''double bubble'' sign were confirmed in 7 fetus. Besides, MR precisely determined the site of occlusion, such as superior part, descending part, horizontal part or ascending part. The postatretic bowel were also clearly displayed by MRI. Conclusions: MRI are good complementary tools to prenatal ultrasonography for identifying small bowel obstruction. MRI could assess the location of the obstruction and the postatretic bowel.

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Virtual poster abstractsMethods: 111 women undergoing first trimester screening were prospectively assessed using 3D ultrasound in order to measure PV using the VOCAL software (Voluson E8, GE). The offline analysis was performed by 4D view software and PV was calculated using VOCAL option (85 • ). Placental quotient (PQ) was calculated by dividing PV by the fetal Crown-rump length (CRL). Spearman's correlation coefficient (ρ) between PV and PAPP-A, free BHCG, UtA mPI were calculated. In addition, PQ correlation with PAPP-A, free BHCG, UtA mPI was assessed. P < 0.05 was considered statistically significant. Results: The mean placental volume was 73.8 mm 3 . There was a weak negative correlation between PV and UtA mPI (ρ = 0.22, P = 0.039, CI -0.1--0.52). No correlation between PV and PAPP-A (ρ = 0.19, p = 0.13), free BHCG (ρ = 0.056, p = 0.61). No correlation between PQ and PAPP-A (ρ = 0.25, P = 0.13), free BHCG (ρ = 0.17, P = 0.21), or UtA mPI (ρ = 0.23, P = 0.11) were found.Conclusions: In our study we found a weak negative correlation between placental volume and uterine artery velocimetry. Therefore, we plan to compare placental volume and uterine artery prediction power for PE and IUGR when the outcomes become available.