Romain Corroenne

Background Approximately half of twin-to-twin transfusion syndrome (TTTS) cases are complicated by selective fetal growth restriction (sFGR). Although fetoscopic laser photocoagulation (FLP) is the standard treatment, perinatal outcomes in cases with concomitant sFGR—particularly according to single or dual fetal survival after laser—are not well established. Objective To compare post-FLP obstetrical and neonatal outcomes between TTTS+sFGR and isolated TTTS, with separate analyses in pregnancies with immediate single or dual fetal survival. Design This was a retrospective cohort study including all TTTS cases treated with FLP at a single institution between November 2011 and April 2023. TTTS was diagnosed according to Quintero criteria. Outcomes included immediate post-FLP fetal demise (48-hour after FLP), preterm premature rupture of membranes (PPROM), gestational age (GA) at delivery, and neonatal survival, according to post-FLP single or dual fetal survival. Results Among 424 cases, 188 (44.3%) had TTTS+sFGR. Gestational age and cervical length at FLP were similar between groups, but TTTS+sFGR cases showed more severe disease, with a higher proportion of Quintero stage III. Dual fetal survival after FLP was lower in TTTS+sFGR compared with iTTTS (79.6% vs. 88.5%). In pregnancies with single fetal survival post-FLP, TTTS+sFGR was associated with higher rates of delivery before 32 weeks (p=0.03) and increased post-FLP PPROM (p=0.03). Ex-donor fetuses in this group had significantly lower survival at birth and at 30 days compared with iTTTS. In cases with dual survival post-FLP, ex-donor survival at birth and at 30 days remained lower in TTTS+sFGR, while no other perinatal outcomes differed. Conclusion When stratified by immediate single or dual post-FLP survival, pregnancies with TTTS complicated by sFGR showed consistently worse obstetrical and neonatal outcomes compared with isolated TTTS, particularly due to reduced ex donor survival across both groups.

Introduction - L'échographie et l'IRM conventionnelle permettent d'étudier, in utero la morphologie cérébrale, mais ne peuvent pas évaluer les modifications micro structurelles qui surviennent au cours du développement cérébral normal ou secondaires à des malformations cérébrales congénitales. En étudiant le mouvement de diffusion des molécules d'eau dans les tissus, l'imagerie en tenseur de diffusion (DTI) permet d'obtenir des informations sur la micro structure des tissus étudiés. Les objectifs de notre étude étaient : 1) étudier le développement cérébral fœtal normal in utero à l'aide de la DTI, 2) étudier la faisabilité de la DTI de moelle épinière in utero, 3) évaluer le potentiel de la DTI dans l'évaluation des pathologies du corps calleux (CC) et 4) évaluer la faisabilité de la DTI des voies optiques fœtales. Méthodes -Nous avons réalisé une étude prospective à la Plateforme Lumière (Paris, France) entre 2019 et 2022 (IRB 2019-A01498-49). Nous avons inclus des femmes enceintes volontaires, ne présentant pas d'anomalie fœtale entre 21 et 36 semaines d'aménorrhées (SA). Nous avons également réalisé une étude rétrospective dans le service de médecine fœtal de l'hôpital Necker (Paris, France) entre 2016 et 2022 et inclus des femmes enceintes adressées pour l'évaluation d'un petit CC fœtal, (longueur cranio caudale inférieure au 5ème percentile) (IRB 00011928). Toutes les participantes ont bénéficié d'une IRM 1.5T sans sédation. Des acquisitions DTI en 16 directions sur un plan axial du cerveau fœtal et un plan sagittal du rachis fœtal ont été réalisées. Les étapes de post-traitement comprenaient : débruitage, correction de l'artefact de Gibbs, correction du courant de Foucault et recalage des plans. Les paramètres DTI suivants ont été obtenus : Fractional anisotropy (FA), Apparent Diffusion Coefficient (ADC), Axial Diffusivity (AD) and Radial Diffusivity (RD). Méthodes - 111 femmes enceintes entre 21 et 36 SA ont été incluses. Dans 85% des cas, l'étude du cerveau fœtal a été possible à l'aide de la DTI. Nous avons décrit pour la première fois, l'évolution des paramètres de DTI dans le cerveau fœtal dans un grand nombre de régions cérébrales (Substance Blanche : 42 ' Substance Grise : 26). Dans une majorité de régions cérébrales, nous avons observé une diminution de la FA jusqu'à 30-32 SA suivi par une augmentation jusqu'à 36SA. Cette évolution pourrait refléter les changements histologiques qui surviennent à la transition entre les phases de pré-myélinisation et de myélinisation des axones du système nerveux central. Afin d'évaluer la faisabilité de la DTI fœtale de moelle épinière in utero, nous avons inclus 35 femmes enceintes entre 21 et 36 SA et démontré la faisabilité de la DTI de la moelle épinière fœtale en conditions normales. Afin d'évaluer la microstructure des petits CC, nous avons inclus 22 fœtus avec une suspicion de petit CC à 31 SA et nous les avons comparés à 66 fœtus avec CC normaux. Des bandelettes de Probst étaient présentes dans 45% des petits CC. En cas de petits CC avec bandelettes de Probst, les paramètres DTI étaient significativement différents comparés aux CC normaux et aux petits CC sans bandelettes de Probst dans toutes les régions du CC. En cas de petits CC sans bandelettes de Probst, il n'y avait pas de différence avec les CC normaux. La DTI du CC pourrait aider à différencier les dysplasies calleuses des variantes de la normale en cas de suspicion de petits CC. Conclusion - Notre étude a mis en évidence des modifications longitudinales des paramètres de DTI dans le cerveau et la moelle épinière fœtal au cours de la grossesse. Ces résultats pourraient aider à caractériser les modifications micro structurelles qui surviennent au cours du développement normal du système nerveux central fœtal. De plus, la DTI pourrait être utile pour redéfinir les anomalies du CC et améliorer le conseil parental en cas de découverte anténatale d'une anomalie cérébrale.

Background Little is known about the impact of spinal cord microstructural alterations after prenatal myelomeningocele (MMC) repair and their associations with neurological clinical assessments. Objective To assess spinal cord diffusivity using diffusion-weighted imaging (DWI) obtained between 10 months and 30 months of age in children who underwent prenatal MMC repair, and to explore associations with neurological clinical assessments. Materials and methods This retrospective cohort study included children who underwent prenatal MMC repair from November 2011 to May 2023. All children met the Management Of Myelomeningocele Study (MOMS) inclusion criteria. DWI (b=0 s/mm² and 800 s/mm²) was performed between 10 months and 30 months of age, and apparent diffusion coefficient (ADC) values were obtained at the level of the spinal lesion. Neurological clinical assessments included intact S1 motor and sensory level, need for anticholinergic therapy or clean intermittent catheterization at the evaluation closest to 12 months, and ambulatory status at the evaluation closest to 30 months. Associations between ADC values (expressed as median [interquartile range]) and neurological clinical assessments were evaluated using the Mann-Whitney U test. A P-value -3 mm²/s, P=0.01), intact S1 sensory level (1.36 [1.12-1.74] vs 1.21 [1.04-1.38]×10^-3 mm²/s, P=0.02), no anticholinergic therapy (1.31 [1.13-1.70] vs 1.22 [1.04-1.40]×10^-3 mm²/s, P=0.04), no catheterization (1.33 [1.04-1.74] vs 1.21 [1.12-1.32]×10^-3 mm²/s, P=0.04), and independent ambulation (1.36 [1.04-1.89] vs 1.19 [1.00-1.46]×10^-3 mm²/s, P=0.02). Conclusion Lower ADC values at the lesion level were associated with worse neurological and urological clinical assessments in children after prenatal MMC repair, suggesting that DWI may provide imaging biomarkers of spinal cord integrity. Graphical Abstract

Objectives: The primary objective was to compare the evaluation of trainees' obstetric and gynecological (OBGYN) ultrasound skills by an in‐person vs remote examiner. The secondary objectives were to compare the assessment of obstetric ultrasound skills using three types of ultrasound simulator vs traditional examination involving a pregnant volunteer, and to evaluate the perspectives of trainees and examiners on the three ultrasound simulators. Methods: This was a prospective study of 12 physicians with minimal experience in OBGYN ultrasound. After completing a structured training course, trainees performed an ultrasound examination at four stations: one involving a mid‐trimester pregnant volunteer (obstetric examination only) and three using ultrasound simulators (OBGYN examination), namely an ultrasound simulator app, a high‐fidelity mannequin simulator and an optical positioning simulator. At each station, two certified maternal–fetal medicine specialists assessed the scans simultaneously, with one examiner present in the room and the other observing remotely via live video. The assessments were based on the 20‐planes approach from the International Society of Ultrasound in Obstetrics and Gynecology Basic Training program and the Objective Structured Assessment of Ultrasound Skills (OSAUS) scale. An anonymous survey was used to gauge the subjective impressions of the maternal–fetal medicine specialists and trainees on the three ultrasound simulators. Results: The image scores from remote vs in‐person assessment using the 20‐planes approach showed moderate‐to‐good agreement across three of the four stations, with intraclass correlation coefficient (ICC) values ranging from 0.51 (95% CI, 0.06–0.80) to 0.89 (95% CI, 0.26–0.99). However, remote assessment of OBGYN ultrasound images obtained using the high‐fidelity mannequin simulator yielded lower scores compared with in‐person assessment, with an ICC of 0.28 (95% CI, −0.32 to 0.72). Additionally, scores on the OSAUS scale obtained remotely differed significantly from those obtained in person for all stations ( P < 0.05 for all). Using the 20‐planes approach, the obstetric image scores obtained during the traditional examination involving a pregnant volunteer were similar to those obtained using the optical positioning simulator, but not to those from the other two simulators. The OSAUS scores were similar only between the ultrasound simulator app and the high‐fidelity mannequin simulator, and between the optical positioning simulator and assessment on a pregnant volunteer, when the assessment was conducted by an in‐person examiner. Examiners and trainees generally agreed that ultrasound simulators offer benefit in the training and assessment of OBGYN ultrasound skills. Conclusions: Simulation‐based techniques show potential for evaluating OBGYN ultrasound competence. It may be possible for evaluation to be conducted remotely by experts certified in maternal–fetal medicine. While promising as an educational and training tool, the role of simulation as a method for remotely assessing ultrasound skills warrants further investigation. © 2026 International Society of Ultrasound in Obstetrics and Gynecology.

Objective: Myelomeningocele (MMC) is associated with significant alterations of the brain microstructure, which can impair long‐term neurodevelopmental outcomes. By measuring the random displacement of water molecules within the brain, magnetic resonance imaging (MRI)‐based diffusion‐weighted imaging (DWI) can provide objective metrics, such as apparent diffusion coefficient (ADC) values, which allow the fetal brain microstructure to be characterized. The aim of this study was to compare prenatal brain ADC values, obtained using MRI‐DWI, between infants with prenatally repaired MMC who had normal vs impaired neurodevelopmental outcomes, assessed ≥ 18 months of age. Methods: This retrospective study included children who underwent prenatal MMC repair using either a fetoscopic or open‐hysterotomy surgical approach between July 2012 and June 2022, at a single tertiary hospital. A 1.5‐Tesla MRI‐DWI scan of the fetal brain was performed using standard departmental protocols 6 weeks after surgery. ADC values were measured in the right and left hemispheric white matter of the frontal, parietal, temporal and occipital lobes, as well as within the basal ganglia, pons, cerebellar hemispheres and vermis. Neurodevelopment was evaluated by a developmental pediatrician at or after 18 months of age, using the Capute Scales (Clinical Adaptive Test (CAT) for problem‐solving skills and fine motor skills and Clinical Linguistic and Auditory Milestone Scale (CLAMS) test for language) and the gross motor domain of the Revised Gesell Developmental Schedules. The Developmental Profile‐3 (DP‐3) test was also conducted during parental interview at or after 18 months of age, which evaluates five qualities of development: physical, adaptive behavior, social–emotional, cognitive and communication skills. Developmental quotients were calculated as: (age equivalent on Capute Scales, gross motor or DP‐3 test/age at assessment) × 100. A normal developmental quotient score was defined as ≥ 85 and a score of < 85 indicated neurodevelopmental impairment (NDI), compared with reference values. ADC values measured in each brain region were compared between children who later had a normal developmental quotient score vs those with a score < 85, using the Mann–Whitney U ‐test and logistic regression analysis, adjusting for the child's age at the time of neurodevelopmental testing, gestational age at the time of MRI‐DWI and gestational age at delivery. Results: A total of 50 children were included (39 that underwent prenatal fetoscopic repair and 11 that underwent prenatal open‐hysterotomy repair). A prenatal MRI‐DWI scan was performed after surgery at a median of 30.9 (interquartile range (IQR), 30.5–31.4) weeks' gestation. The Capute Scales and gross motor scores were available in 31/50 (62.0%) and 29/50 (58.0%) cases, respectively, and were obtained at a median age of 23.0 (IQR, 18.0–25.5) months and 23.0 (IQR, 21.0–26.2) months, respectively. Among these cases, 22/31 (71.0%), 19/31 (61.3%) and 3/29 (10.3%) scored ≥ 85 on the CLAMS test, CAT and gross motor test, respectively. The DP‐3 test score was available in 42/50 (84.0%) children and was conducted at a median age of 24.5 (IQR, 19.0–26.7) months. Among these children, 18/42 (42.9%), 28/42 (66.7%), 38/42 (90.5%), 35/42 (83.3%) and 33/42 (78.6%) had a score ≥ 85 for the physical, adaptive behavior, social–emotional, cognitive and communication domains, respectively. After adjustment, fetal ADC values obtained 6 weeks after surgery were significantly higher in all fetal brain regions studied ( P < 0.05 for all), except for the vermis ( P = 0.12) and pons ( P = 0.05), in infants who later had a CLAMS test score indicating NDI compared to those with a score ≥ 85. Additionally, fetal ADC values were significantly higher in all fetal brain regions, except for the left temporal lobe ( P = 0.05), left occipital lobe ( P = 0.06), pons ( P = 0.30), right and left cerebellum ( P = 0.55 and 0.24, respectively) and vermis ( P = 0.76), in infants who later had a CAT score indicating NDI compared to those with a normal score. Fetal ADC values were also significantly higher in the parietal and temporal lobes as well as in the pons ( P < 0.05 for all) in infants who later had a DP‐3 cognitive and communication score indicating NDI compared to those with a normal score. There was no difference in fetal ADC values in any of the brain regions studied between children with scores indicating normal vs impaired neurodevelopment on the gross motor test, the DP‐3 physical, adaptive behavior and social–emotional domains or the DP‐3 general development score. Conclusion: Infants with NDI in problem‐solving, cognitive and communication skills exhibited significant differences in their brain microstructure, as demonstrated by higher ADC values measured in utero 6 weeks after prenatal MMC repair, compared to those with normal neurodevelopmental outcomes as assessed at or after 18 months of age. These findings have significant clinical implications, especially for the early identification and management of children at risk for NDI after prenatal MMC repair. © 2026 The Author(s). Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Background and Purpose: Chiari II deformation in open neural tube defect (ONTD) includes hindbrain herniation (HBH) and posterior fossa remodeling. While HBH reversal after prenatal ONTD repair is well described, associated changes in cerebellar morphology, torcular position, and bony configuration remain poorly characterized. This study evaluated longitudinal changes in posterior fossa anatomy following fetal ONTD repair and their associations with HBH reversal and evolving ventriculomegaly. Methods: We retrospectively reviewed 112 fetuses who underwent prenatal ONTD repair at a single center (2011–2023), each with fetal MRI before surgery (median 22.9 [19.1–25.4] weeks) and 6 weeks after surgery (31.4 [28.6–34.0] weeks). Two independent examiners assessed cerebellar and brainstem position, occipital bone outpouching, clivus concavity, torcular position, and preservation of supratentorial subarachnoid space. HBH reversal was defined as cerebellar ascent above the foramen magnum. Severe ventriculomegaly was defined as a mean atrial width ≥15 mm. Associations were tested using Chi‐square or McNemar tests. Results: At referral, 17.9% had severe ventriculomegaly and 79.5% had lesions below L2. After surgery, clivus concavity (97.3% vs 84.1%, p p p <0.01). Severe ventriculomegaly at postoperative MRI (58.9%) was not associated with posterior fossa abnormalities. Conclusions: Prenatal ONTD repair improves HBH and supratentorial CSF space preservation but has limited impact on deeper posterior fossa remodeling, which appears only partially reversible.

Objective: The corpus callosum (CC) is an interhemispheric structure that facilitates communication between the two cerebral hemispheres. Anomalies of the CC are frequent and associated with a wide spectrum of altered neurodevelopmental outcomes. However, variability in diagnostic criteria and the lack of standardized management strategies create challenges for clinicians and anxiety for expectant parents. This study aimed to establish an international consensus on the prenatal evaluation, diagnosis and management of fetal CC abnormalities using a structured Delphi methodology. Methods: A three‐round Delphi process was conducted among an international panel of fetal medicine experts, identified based on clinical expertise and publication history. Structured statements regarding CC evaluation, diagnosis and management were developed through expert input and a scoping literature review. The statements were iteratively refined and scored by the panel using a five‐point Likert scale in the first two rounds. During the final round, consensus was defined as > 70% agreement among participants. Results: Fifty‐five experts participated in the first round, with 43 (78.2%) experts completing the entire process. Key consensus findings included the incorporation of obtaining a sagittal view of the brain in routine ultrasound screening (72.4% agreement), without requiring measurement even when an anomaly is suspected (93.1% agreement), but instead with recommended referral to a specialist (100% agreement). For diagnostic ultrasound, three‐dimensional ultrasound imaging (72.4% agreement) and transvaginal ultrasound evaluation (82.8% agreement) were recommended, with targeted measurements of CC length in the case of a subjective impression of abnormal size (82.8% agreement). However, it was agreed that there is no consensus on the reference chart or cut‐off values to be used for defining abnormal CC length (86.2% and 89.3% agreement, respectively). In terms of management, it was agreed that both an invasive genetic workup and magnetic resonance imaging (MRI) should be offered in case of suspected dysgenesis of the CC (100% agreement). MRI should be performed if the CC appears to be too short (100% agreement), thin (100% agreement) or thick (92.0% agreement). In the case of an isolated CC with heterogeneous echogenicity, an infectious workup is recommended (86.2% agreement). Conclusion: This study provides a structured framework for the evaluation and management of fetal CC abnormalities. By standardizing approaches to imaging and management, the recommendations aim to improve diagnostic accuracy, optimize patient outcomes and reduce unnecessary interventions. Further prospective studies are needed to validate these recommendations and assess their impact on clinical care. © 2025 The Author(s). Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.