F. Fontanella

Fetal megacystis: prediction of spontaneous resolution and outcome

To investigate the natural history of fetal megacystis from diagnosis in utero to postnatal outcome, and to identify prognostic indicators of spontaneous resolution and postnatal outcome after resolution.

Antenatal staging of congenital lower urinary tract obstruction

To propose a staging system for congenital lower urinary tract obstruction (LUTO) capable of predicting the severity of the condition and its prognosis.

Fetal megacystis: a lot more than LUTO

Fetal megacystis presents a challenge in terms of counseling and management because of its varied etiology and evolution. The aim of this study was to present a comprehensive overview of the underlying etiologies and structural anomalies associated with fetal megacystis.

Antenatal Workup of Early Megacystis and Selection of Candidates for Fetal Therapy

Objective: To investigate the best criteria for discriminating fetuses with isolated posterior urethral valves from those theoretically not eligible for fetal treatment because of complex megacystis, high chance of spontaneous resolution, and urethral atresia. Methods: A retrospective national study was conducted in fetuses with megacystis detected before 17 weeks’ gestation (early megacystis). Results: In total, 142 cases with fetal megacystis were included in the study: 52 with lower urinary tract obstruction, 29 with normal micturition at birth, and 61 with miscellaneous syndromal associations, chromosomal and multiple structural abnormalities (complex megacystis). Only a nuchal translucency > 95th centile, and not a longitudinal bladder diameter ≤15 mm (p = 0.24), significantly increased the risk of complex megacystis (p < 0.01). Cases with a high chance of spontaneous resolution were identified by using the cut-off of 12 mm, as demonstrated in a previous study, and the finding of an associated umbilical cord cyst carried a high-risk of urethral atresia (odds ratio: 15; p = 0.026), an unfavorable condition for antenatal treatment. An algorithm encompassing these three criteria demonstrated good accuracy in selecting fetuses theoretically eligible for fetal treatment (specificity 73%; sensitivity 92%). Conclusions: Cases theoretically eligible for early fetal therapy are those with normal nuchal translucency, a longitudinal bladder diameter > 12 mm, and without ultrasound evidence of umbilical cord cysts.

Prenatal diagnosis of LUTO: how to improve diagnostic accuracy

To propose a clinical score for the optimal antenatal diagnosis of fetal lower urinary tract obstruction (LUTO) in the second and third trimesters of pregnancy, as an alternative to the commonly used ultrasound triad of megacystis, keyhole sign and hydronephrosis.

Grading the fetal echogenic bowel (EB): correlation between quantitative computerissed gray-scale analysis and subjective qualitative evaluation

Results: The coefficients of variation in mature fetuses were greater than 30% for placentas in-vivo, greater than 35 for placentas in-vitro, greater than 29% for liver tissue and greater than 33% for lung tissue. In mature fetuses strain index (SI) for fetal lung was greater than 0,9, for placentas in vivo greater than 1,0, for placentas in vitro, greater than 1,5, for liver tissue greater than 0,7. We found significant difference in SI in normal pregnancies comparing with pre-eclamptic pregnancies and diabetic pregnancies. We did not find significant difference between lung volumes in all investigated patients. Conclusions: The coefficient of variation values and strain stiffness for placentas in vivo and in vitro, and fetal lungs and liver increase during pregnancy in normal and pre-eclamptic patients with increasing gestational age and decrease in diabetic patients. Lung volumes increase during pregnancy in normal, pre-eclamptic and diabetic patients.

OC18.05: Echogenicity of the fetal bowel using histogram gray‐scale analyser: a comparison between normal fetuses and fetuses with echogenic bowel (EB)

Objectives: To evaluate fetal breathing movements using ultrasound-based tracking technique in fetuses with intrauterine growth restriction (IUGR) and appropriate-for-gestational-age (AGA). Methods: A prospective study was performed in 10 IUGR (estimated fetal weight <3rd centile) and 7 AGA fetuses, using ultrasound-based computer-aided tracking technique of fetal breathing movement analysis in a tertiary referral centre. For each breath, total, inspiration and expiration durations were measured. Breaths per minute and breath to breath variability were calculated. Breath to breath variability was defined as the mean absolute difference of breath to breath duration. All breathing data were collected before antenatal corticosteroid administration. The fetal breathing movement data were extracted from ultrasound video recordings by tracing the movement of the boundary defined by the fetal thorax spanning multiple frames. Single fetal respiration cycle was observed as the consecutive local minima points of the fetal breathing movement signal (boundary displacement). Results: A total of 1044 breathing movements were analysed in 17 fetuses. Mean number of breathing movement per fetus was 61.5 (range 28–123). Mean gestational age at scan was similar between IUGR and AGA groups (33.5 vs. 33.9, respectively, p=0.807). Mean breath, inspiration and expiration durations were lower and variability was higher in IUGR group but the differences did not reach statistical significance (see table 1). Conclusions: Our study suggests that ultrasound-based computer-aided tracking technique can be used to analyse fetal breathing parameters. Further studies are needed to assess the clinical use of this technique.

P28.03: Reference curves for fetal urinary bladder and renal pelvis volumes in the second and third trimester of pregnancy

Objectives: Anorectal malformation are usually under diagnosed. The main goal of this study was to establish prenatal ultrasound references value for perineal muscular complex, anogenital distance for future perspective of antenatal diagnosis improvement. Methods: The perineal muscular complex was visualised and measured in the longitudinal axis. When it couldn’t be seen easily, a three-dimensional ultrasonography with tomography ultrasonography imaging was used and perineal muscular complex appeared on tangential axis. Tomography ultrasonography imaging or triplane application were used to show rectum, anal canal and skin perineum part and measure was performed in the skin perineum part. Then anogenital distance was measured. Anorectal angle was measured as the angle formed between the rectum and the anal canal, and the results were expressed in degrees. All data processing was performed using SPSS 20. Results: A total of 259 fetuses were examined by ultrasound. Maternal age ranged from 19 to 44 years (mean, 30.6 y; SD±5.6). Gestational age at measurement ranged from 19 to 41 weeks (mean, 31 weeks; SD±6). Normal fetal perineal muscular complex diameter ranged from 5 to 23 mm (mean 12.82 mm; SD, ±5.6mm). The measurement of anogenital distance ranged from 4.7 to 40 mm (mean, 16.8; SD±7.4). Anorectal angle mean was 111.89◦ ranging from 100.83◦ and 118.96◦. There was a significant positive relationship between perineal muscular complex diameter, anogenital distance, anorectal angle and gestational age (p<0.005). Conclusions: Establishment and application of normogram for measurements could be the first step to improve our antenatal diagnosis and post-natal surgical management.

Antenatal diagnosis of lower urinary tract obstructions (LUTO): a prediction model to improve the diagnostic accuracy

F. Fontanella6, L. Duin6, P. Adama Van Scheltema3, T.E. Cohen-Overbeek2, E. Pajkrt1, M.N. Bekker5,7, C. Willekes4, C. Bax8, V. Gracchi9, D. Oepkes10, C.M. Bilardo6 1Obstetrics, Academic Medical Centre, Amsterdam, Netherlands; 2Obstetrics and Gynecology, Erasmus University Medical Centre, Rotterdam, Netherlands; 3Prenatal Diagnosis and Therapy, LUMC, Leiden, Netherlands; 4Obstetrics and Gynecology, MUMC, Maastricht, Netherlands; 5UMCU, Utrecht, Netherlands; 6University Medical Centre Groningen, Groningen, Netherlands; 7Radboud UMC, Nijmegen, Netherlands; 8VU University Medical Centre Amsterdam, Amsterdam, Netherlands; 9Department of Pediatrics, University Medical Centre Groningen, Groningen, Netherlands; 10Leiden University Medical Centre, Leiden, Netherlands

Prenatal Evidence of Persistent Notochord and Absent Sacrum Caused by a Mutation in the T (Brachyury) Gene

Caudal regression syndrome (CRS) is a rare congenital disorder characterized by developmental abnormalities of caudal spinal segments. To date, the etiology of CRS is unclear; sporadic cases are strongly associated with maternal diabetes, while familiar recurrence is infrequent. We describe in detail the prenatal clinical and sonographic findings of a recently described hereditary caudal regression syndrome, in four fetuses reported to be homozygous for a mutation in the T (brachyury) gene. The syndrome occurred in three consanguineous, but unrelated families, originating from the same geographical area. All affected fetuses had persistence of the notochord in association with abnormal vertebral ossification, sacral agenesis, and bilateral clubfoot. These findings suggest that, in case of prenatal diagnosis of sacral agenesis, an advanced ultrasound examination should assess the vertebral ossification and the rare persistence of the notochord, in order to rule the involvement of the T gene.