Z-scores of fetal bladder size for antenatal differential diagnosis between posterior urethral valves and urethral atresia.

OBJECTIVE: To construct reference values for fetal urinary bladder distension in pregnancy and use Z-scores as a diagnostic tool to differentiate posterior urethral valves (PUV) from urethral atresia (UA). METHODS: This was a prospective cross-sectional study in healthy singleton pregnancies aimed at constructing nomograms of fetal urinary bladder diameter and volume between 15 and 35 weeks' gestation. Z-scores of longitudinal bladder diameter (LBD) were calculated and validated in a cohort of fetuses with megacystis with ascertained postnatal or postmortem diagnosis, collected from a retrospective, multicenter study. Correlations between anatomopathological findings, based on medical examination of the infant or postmortem examination, and fetal megacystis were established. The accuracy of the Z-scores was evaluated by receiver-operating-characteristics (ROC)-curve analysis. RESULTS: Nomograms of fetal urinary bladder diameter and volume were produced from three-dimensional ultrasound volumes in 225 pregnant women between 15 and 35 weeks of gestation. A total of 1238 urinary bladder measurements were obtained. Z-scores, derived from the fetal nomograms, were calculated in 106 cases with suspected lower urinary tract obstruction (LUTO), including 76 (72%) cases with PUV, 22 (21%) cases with UA, four (4%) cases with urethral stenosis and four (4%) cases with megacystis-microcolon-intestinal hypoperistalsis syndrome. Fetuses with PUV showed a significantly lower LBD Z-score compared to those with UA (3.95 vs 8.83, P < 0.01). On ROC-curve analysis, we identified 5.2 as the optimal Z-score cut-off to differentiate fetuses with PUV from the rest of the study population (area under the curve, 0.84 (95% CI, 0.748-0.936); P < 0.01; sensitivity, 74%; specificity, 86%). CONCLUSIONS: Z-scores of LBD can distinguish reliably fetuses with LUTO caused by PUV from those with other subtypes of LUTO, with an optimal cut-off of 5.2. This information should be useful for prenatal counseling and management of LUTO. © 2021 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Fetal megacystis: a lot more than LUTO.

OBJECTIVE: 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. METHODS: This was a retrospective multicenter study of cases referred to the fetal medicine unit of one of the eight academic hospitals in The Netherlands with a diagnosis of fetal megacystis. For each case, data on and measurements of fetal urinary tract and associated structural anomalies were collected. All available postmortem examinations and postnatal investigations were reviewed in order to establish the final diagnosis. In the first trimester, fetal megacystis was defined as longitudinal bladder diameter (LBD) ≥ 7 mm, and in the second and third trimesters as an enlarged bladder failing to empty during an extended ultrasound examination lasting at least 40 min. RESULTS: Of the 541 pregnancies with fetal megacystis, it was isolated (or solely accompanied by other signs of lower urinary tract obstruction (LUTO)) in 360 (67%) cases and associated with other abnormal ultrasound findings in 181 (33%) cases. The most common associated ultrasound anomaly was an increased nuchal translucency thickness (22%), followed by single umbilical artery (10%) and cardiac defect (10%). A final diagnosis was established in 418 cases, including 222 (53%) cases with isolated LUTO and 60 (14%) infants with normal micturition or minor isolated urological anomalies. In the remaining 136 (33%) cases, concomitant developmental or chromosomal abnormality or genetic syndrome was diagnosed. Overall, 40 chromosomal abnormalities were diagnosed, including trisomy 18 (n = 24), trisomy 21 (n = 5), Turner syndrome (n = 5), trisomy 13 (n = 3) and 22q11 deletion (n = 3). Thirty-two cases presented with anorectal malformations involving the anus, rectum and urogenital tract. In cases with confirmed urethral and anal atresia, megacystis occurred early in pregnancy and the bladder appeared severely distended (the LBD (in mm) was equal to or greater than twice the gestational age (in weeks)). Fetal macrosomia was detected in six cases and an overgrowth syndrome was detected in four cases, comprising two infants with Beckwith-Wiedemann syndrome and two with Sotos syndrome. Megacystis-microcolon-intestinal hypoperistalsis syndrome was diagnosed in five (1%) cases and prenatally suspected only in one case. CONCLUSIONS: Although the main cause of fetal megacystis is LUTO, an enlarged fetal bladder can also be present as a concomitant finding of miscellaneous genetic syndromes, developmental disturbances and chromosomal abnormalities. We provide an overview of the structural anomalies and congenital disorders associated with fetal megacystis and propose a practical guide for the differential diagnosis of genetic syndromes and chromosomal and developmental abnormalities in pregnancies presenting with fetal megacystis, focusing on the morphological examination of the fetus. © 2018 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology.

Prenatal diagnosis of LUTO: improving diagnostic accuracy.

OBJECTIVE: 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. METHODS: This was a national retrospective study carried out at the eight tertiary fetal medicine units (FMUs) in The Netherlands. Only cases referred for megacystis from the second trimester onwards and with a clear postnatal diagnosis were included in the study. At referral, data were collected on amniotic fluid volume, renal cortical appearance, bladder volume, hydronephrosis, fetal ascites, ureteral size, keyhole sign, fetal sex and gestational age. Multivariate analysis was performed, starting by including all antenatal variables, and then excluding the weakest predictors using the backward stepwise strategy. RESULTS: Over a 7-year period, 312 fetuses with a diagnosis of megacystis were referred to the eight Dutch tertiary FMUs. A final diagnosis was achieved in 143 cases, including 124 of LUTO and 19 reclassified after birth as non-obstructive megacystis. The optimal bladder volume cut-off for prediction of LUTO was 35 cm3 (area under the curve (AUC) = 0.7, P = 0.03). The clinical score formulated on the basis of the multivariate analysis included fetal sex, degree of bladder distension, ureteral size, oligo- or anhydramnios and gestational age at referral. The combination of these five variables demonstrated good accuracy in discriminating LUTO from non-obstructive megacystis (AUC = 0.84, P < 0.001), compared with the poor performance of the ultrasound triad (AUC = 0.63, P = 0.07). CONCLUSIONS: We propose a clinical score that combines five antenatal variables for the prospective diagnosis of congenital LUTO. This score showed good discriminative capacity in predicting LUTO, and better diagnostic accuracy compared with that of the classic ultrasound triad. Future studies to validate these results should be carried out in order to refine antenatal management of LUTO and prevent inappropriate fetal interventions. © 2017 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology.

Comparison of conventional versus three-dimensional ultrasound in fetal renal pelvis measurement and their potential prediction of neonatal uropathies.

OBJECTIVE: To establish a threshold value for fetal renal pelvis dilatation measured by automatic volume calculation (SonoAVC) in the third trimester of pregnancy to predict neonatal uropathies, and to compare these results with conventional antero-posterior (AP) measurement, fetal kidney 3D volume and renal parenchymal thickness. METHODS: In a prospective cohort study, 125 fetuses with renal pelvis AP diameter of ≥5 mm both at 20 weeks of gestation and in the third trimester, underwent an additional 3D volume measurement of the fetal kidney in the third trimester. Receiver operating characteristic (ROC) curves for establishing threshold values for fetal renal pelvis volume, AP measurement, fetal kidney volume and renal parenchymal thickness to predict neonatal uropathies were analyzed. Also, sensitivity, specificity, area under the curve (AUC) and likelihood ratios were calculated. RESULTS: A cut-off point of 1.58 cm³ was identified in the third trimester of pregnancy (AUC 0.865 (95% CI 0.789-0.940), sensitivity 76.3%, specificity 87.4%, LR+ 6.06, LR- 0.27) for measurements with SonoAVC. A cut-off value of 11.5 mm was established in the third trimester of pregnancy (AUC 0.828 (95% CI 0.737-0.918), sensitivity 71.1%, specificity 85.1%, LR+ 4.77, LR- 0.34) for the conventional AP measurement. A cut-off point for fetal kidney volume was calculated at 13.29 cm³ (AUC 0.769 (95% CI 0.657-0.881), sensitivity 71%, specificity 66%, LR+ 2.09, LR- 0.44). For renal parenchymal thickness, a cut-off point of 8.4 mm was established (AUC 0.216 (95% CI 0.117-0.315), sensitivity 31.6%, specificity 32.6%, LR+ 0.47, LR- 2.10). CONCLUSION: This study demonstrates that 3D fetal renal pelvis volume measurements and AP measurements both have a good and comparable diagnostic performance, fetal renal volume a fair accuracy and renal parenchymal thickness a poor accuracy in predicting postnatal renal outcome.

Reproducibility of fetal renal pelvis volume assessed by three-dimensional ultrasonography with two different measurement techniques.

PURPOSE: To evaluate reproducibility of fetal renal pelvis volume as assessed by the Virtual Organ Computer Aided AnaLysis (VOCAL) imaging program and by Automatic Volume Calculation (SonoAVC). In addition, the intra- and interobserver reliability of fetal renal pelvis volume measurements with SonoAVC were established. METHODS: In this study, the fetal renal pelvis volume was measured using 3D ultrasonography in 76 kidneys of 66 fetuses with renal pelvis dilatation in the second or third trimester of pregnancy. After volume acquisition by one observer, the reproducibility of volume calculation was assessed using VOCAL imaging program and SonoAVC by two observers. Intra- and interobserver reproducibility was evaluated by calculating intraclass correlation coefficients (ICC), coefficient of variation (CV) and repeatability coefficient (r). Bland-Altman plots were generated to explore agreement. RESULTS: A high degree of reproducibility was observed between VOCAL and SonoAVC, ICC of 0.989; 95% CI 0.983-0.993, respectively. Intraobserver reproducibility of volume measurements performed by SonoAVC demonstrated a high degree of reliability with ICC of 0.995 (95% CI 0.993-0.997), CV 6.05% and r of 0.75. The interobserver reproducibility with ICC of 0.995 (95% CI 0.992-0.997), CV 10.14% and r 1.21 was also indicative of good reliability. CONCLUSION: Volume measurements of fetal renal pelvis performed by SonoAVC renders reproducible measurements in comparison with the VOCAL imaging program. There is no significant difference between VOCAL imaging program and SonoAVC. The intra- and interobserver reliability of the fetal renal pelvis measurements made by SonoAVC were considered to be very good. SonoAVC, however, needs post processing in the majority of cases but is less time consuming than VOCAL.

Fetal hydronephrosis: does adding an extra parameter improve detection of neonatal uropathies?

OBJECTIVE: The aim of this study is to assess the correlation of the average antero-posterior, transverse and longitudinal diameters of the fetal renal pelvis to neonatal outcome. METHODS: This retrospective study evaluates the neonatal outcome of all fetuses with suspected pyelectasis on ultrasonographic examination between May 1997 and March 2006. During this time, 764 fetuses with pyelectasis and 1285 renal units were scanned. We defined fetal pyelectasis as mild if the ARP was ≥ 5-<10 mm, moderate if ARP ≥ 10-<15 mm and severe if ARP ≥ 15 mm. A total of 612 fetuses met the inclusion criteria. The Corteville criteria in the third trimester (antero-posterior diameter ≥ 7 mm) and an antero-posterior diameter (AP) of ≥ 10 mm were compared with the ARP and likelihood ratio's calculated. Ultrasonographic evaluation took place in the third trimester if fetal pyelectasis was diagnosed as an isolated finding in the second trimester. This last ultrasonographic examination was used for final analysis and as a guideline for postnatal follow-up. Neonatal outcome was assessed by reviewing medical records, ultrasonographic, renographic and voiding cysto-urethrographic results. RESULTS: Of all the fetuses diagnosed with renal pelvis dilatation in the third trimester of pregnancy, 73 (11.9%) infants needed postnatal surgery. The majority of the postnatal surgery was performed in the group of fetuses with severe hydronephrosis (8.2%). This resulted in a LR of 5.81 and a post-test probability of 61.3%. In total, 78.8% of the fetuses with hydronephrosis had spontaneous resolution across all grades of severity on the first postnatal ultrasonogaphic investigation or during their follow-up. In 9.3% of the cases, uropathies were diagnosed, but no surgical intervention had taken place during the follow-up period. Using the Corteville criteria as gold standard for the third trimester (AP ≥ 7 mm), 11 (1.8%) patients would not have been diagnosed with uropathies. And in the case of AP ≥ 10 mm, 5.1% of the cases would have been missed. CONCLUSION: An ARP of ≥ 5 mm in the second and/or third trimester of pregnancy enables a better detection of patients with uropathies and indication for surgery as compared with AP ≥ 10 mm, but renders almost similar results compared with the Cortville criteria (AP ≥ 7 mm) in the third trimester.

Reproducibility of fetal renal pelvis volume measurement using three-dimensional ultrasound.

OBJECTIVE: To assess the reproducibility of fetal renal pelvis volume measurement in hydronephrotic kidneys using transabdominal three-dimensional (3D) ultrasound. METHODS: The fetal renal pelvis volume was measured using 3D ultrasound in one kidney in each of 15 fetuses with hydronephrosis in the second or third trimester of pregnancy. Hydronephrosis was diagnosed when the fetus had an anteroposterior renal pelvis diameter > or = 5 mm. After volume acquisition by one of the observers, the repeatability of volume calculation with manual delineation of the fetal renal pelvis was assessed by six different observers using the Virtual Organ Computer-aided AnaLysis (VOCAL(trade mark)) imaging program. The intraclass correlation coefficients (ICC), coefficient of variation (CV) and within- and between-observer repeatability coefficient (r) were calculated and Bland-Altman plots were constructed. RESULTS: Both intra- and interobserver reliability of the fetal renal pelvis volume measurements were considered to be very good. For intraobserver reliability, the ICC was 0.996 and the CV was 10.8%. For the overall interobserver reliability, the ICC was 0.998 and the CV was 15.7%; the interobserver reliability between pairs of observers had ICCs between 0.994 and 0.999, and CVs between 19.5% and 7.6% for inexperienced and experienced observers, respectively. CONCLUSION: With 3D ultrasound using the VOCAL imaging program, it is technically feasible to reproduce fetal renal pelvis volume measurements. Further research to establish the clinical applications of this technology is warranted.

Major brain lesions by intrauterine herpes simplex virus infection: MRI contribution.

The majority of neonatal Herpes Simplex Virus (HSV) infections are acquired at birth as a consequence of direct fetal contact with the infected birth canal or through an ascending infection after premature rupture of the amniotic membranes. Intrauterine transmission of HSV infection from mother to the fetus is rare; in only 5% of the cases it occurs from haematogenous transplacental dissemination. We present a case of transplacental intrauterine HSV infection after a primary maternal HSV infection in the first trimester of pregnancy. The diagnosis was assessed by viral culture and serologic tests. Ultrasound imaging revealed fetal brain damage in the third trimester. Finally, the MRI showed the devastating extensiveness of the HSV infection, which was beyond the expectation based on the ultrasound images.