Fetal anterior abdominal wall defects: prenatal imaging by magnetic resonance imaging

Standardised and structured reporting in fetal magnetic resonance imaging: recommendations from the Fetal Task Force of the European Society of Paediatric Radiology

Over the last decades, magnetic resonance imaging (MRI) has emerged as a valuable adjunct to prenatal ultrasound for evaluating fetal malformations. Several radiological societies advocate for standardised and structured reporting practices to enhance the uniformity of imaging language. Compared to narrative formats, standardised and structured reports offer enhanced content quality, minimise reader variability, have the potential to save reporting time, and streamline the communication between specialists by employing a shared lexicon. Structured reporting holds promise for mitigating medico-legal liability, while also facilitating rigorous scientific data analyses and the development of standardised databases. While structured reporting templates for fetal MRI are already in use in some centres, specific recommendations and/or guidelines from international societies are scarce in the literature. The purpose of this paper is to propose a standardised and structured reporting template for fetal MRI to assist radiologists, particularly those with less experience, in delivering systematic reports. Additionally, the paper aims to offer an overview of the anatomical structures that necessitate reporting and the prevalent normative values for fetal biometrics found in current literature.

Optimizing prenatal diagnosis and referral of classic bladder exstrophy: Lessons from a single-institution experience

INTRODUCTION

Classic bladder exstrophy (CBE) is a malformation of the genitourinary system that occurs due to failure of abdominal wall closure. Unlike other malformations of similar incidence, prenatal diagnosis of CBE relies on suggested, rather than formal, diagnostic criteria.

OBJECTIVE

This report describes prenatal diagnosis of CBE in the largest single-institutional cohort to date and delineates key sonographic findings and protocols for specialist referral.

MATERIALS AND METHODS

A single-institutional database was reviewed for CBE patients born since 2000. Data on screening ultrasound use, gestational age at ultrasound, and abnormal findings were extracted. Where possible, time of prenatal diagnosis (pre- or postnatal and gestational age), ultrasound findings and other imaging data, specialist referral, institution of birth and closure, and outcome of primary closure attempt were compared.

RESULTS

Of 557 patients born with CBE between 2000 and 2022, 284 met inclusion criteria and complete data were available for 280 (229 born domestically and 51 born internationally) who were included for analysis. Abnormal sonography suggestive of CBE was present for 48% (n = 134) of patients, for whom absent bladder was the most common abnormal finding (76% [102/134]). Of domestic patients, 46% (n = 106) were diagnosed prenatally at a median gestational age of 22 weeks (inter-quartile range [IQR]: 20-24), and 14% (n = 32) underwent confirmatory fetal magnetic resonance imaging. Of domestic patients with abnormal prenatal findings, 75% (n = 80/106) consulted with maternal-fetal medicine and 58% (n = 62/106) consulted with pediatric urology. On univariate analysis, prenatal diagnosis was positively associated with primary repair at Association for the Bladder Exstrophy Community-recognized centers of excellence (54% vs. 38%, p = 0.02) and negatively associated with osteotomy at primary closure (41% vs 59%, p = 0.003) but not success of primary closure (74% vs. 82%, p = 0.07).

DISCUSSION

Rates of prenatal diagnosis in this cohort were similar to previous reports of smaller cohorts. Diagnosis allows for comprehensive pre- and postnatal follow-up with a pediatric urologist, with implications on birth planning and decisions on termination of pregnancy. Because of the previously-reported association between exstrophy and in vitro fertilization, these pregnancies should undergo detailed sonography. Any nonvisualization of the fetal bladder should prompt a detailed exam, and any finding characteristic of bladder exstrophy warrants referral to pediatric urology.

CONCLUSIONS

Although CBE is a rare disorder, it is underdiagnosed during pregnancy. Sonographers and obstetricians should be aware of characteristic findings and best practices following diagnosis. Early referral to pediatric urology and maternal-fetal medicine is important for counseling and postnatal planning.

MR Imaging of the Fetal Genitourinary Tract

Fetal MR imaging overcomes many of the technical barriers of ultrasound and is an important diagnostic tool for fetal genitourinary (GU) anomalies. It is suited for evaluation of GU anomalies because of the fluid-sensitive sequences and superior soft tissue contrast. Often GU malformations are part of a multisystem genetic or congenital condition, and imaging the entire fetus with MR adds additional clarity about the extent of disease. It adds confidence to diagnoses of renal agenesis, urinary tract dilation, cystic disease, and tumors. It is particularly useful to delineate anatomy in complex GU malformations. This additional information guides counseling.

Limb-body wall complex: Literature review and case report

INTRODUCTION

Body wall anomalies comprise a wide range of malformations. Limb-Body wall complex (LBWC) represents the most severe presentation of this group, with life threatening malformations in practically all the cases, including craniofacial, body wall defects, and limb anomalies. There is no consensus about its etiology and folding and gastrulation defects have been involved. Also, impaired angiogenesis has been proposed as a causative process.

CASE REPORT

We present the case of a masculine stillborn, product of the first pregnancy in a 15-year-old, apparently healthy mother. He was delivered at 31 weeks of gestation due to an early rupture of membranes. He presented with multiple malformations including a wide body wall defect with multiple organ herniation and meromelia of the lower right limb.

DISCUSSION AND CONCLUSIONS

LBWC represents a severe and invariably fatal pathology. There are no described risk factors, nevertheless, this case presented in a teenage mother, a well-described risk factor for other body wall anomalies. Its diagnosis allows us to discriminate between other pathologies that require prenatal or postnatal specialized treatment.

Magnetic resonance imaging of fetal abdominal pathology: a complementary tool to prenatal ultrasound

Fetal magnetic resonance imaging (MRI) is increasingly being used worldwide as a complementary tool to prenatal ultrasound (US) for multiple fetal pathologies. The aim of this article is to describe and illustrate how MRI can help US to evaluate fetal abdominal anomalies, based on cases performed in a tertiary public university hospital. Prenatal US, fetal MRI and postnatal imaging of these cases will be shown side-by-side to describe and illustrate the added value of fetal MRI in the different organs/systems and its impact on clinical management.

A Review of Covered Abdominal Wall Defects: Cord Hernias Are Associated With Major Anomalies

INTRODUCTION

Covered abdominal wall defects (CAWD) can be categorized into giant omphaloceles (GOs), nongiant omphaloceles (NGOs), and umbilical cord hernias (UCHs). We sought to evaluate differences in management and outcomes of the different CAWD, treated at a large tertiary children's hospital, with regards to survival and association with other major congenital anomalies.

METHODS

A retrospective review of CAWD patients between January 2010 and January 2021 was conducted. GO was defined as a fascial defect >5 cm or >50% liver herniation. UCH were defined as fascial defects ≤ 2 cm. All others were classified as NGO. Type of repair, time to fascial closure, index hospitalization length of stay (LOS), and survival rates were compared. Four major anomaly categories were identified: cardiac, midline, Beckwith-Weidemann Syndrome, and other genetic anomalies.

RESULTS

We identified 105 CAWD patients (UCH n = 40; GO n = 34; and NGO n = 31). Ninety percent of UCH underwent primary repair, 10% were never repaired. NGOs were repaired by primary or staged methods in 92.9% of cases and 7.1% by delayed repair. Primary or staged repair occurred in 32.4% of GOs and delayed repair occurred in 67.6%. The median days to repair was 181 [24,427] GO, 1 [1,3] NGO, and 1 [0,1] UCHs (P < 0.01). Index hospitalization median LOS (days) was 90 [55,157] GO, 23 [10,48] NGO, 9 [5,22] UCH, (P < 0.01). There were no statistical differences in survival rates, number of patients with major anomalies (GO 35.4%, NGO 51.5%, UCH 50%), or types of anomalies.

CONCLUSIONS

UCHs and omphaloceles have similar incidences of major associated anomalies. Thus, all patients with a covered abdominal wall defect should undergo workup for associated anomalies.

Abdominal Wall Defects: A Review of Current Practice Guidelines

The 2 most common congenital abdominal wall defects are gastroschisis and omphalocele. Gastroschisis is a defect in the abdominal wall with exposed abdominal contents. Mortality rates are low but lengths of stay are often prolonged by bowel dysmotility and other intestinal abnormalities in complicated cases. Omphalocele is a defect through the umbilical cord with herniated abdominal contents covered by a sac. It is associated with other genetic abnormalities and other anomalies that can lead to significant morbidity and mortality. Prenatal diagnosis in both conditions allows for improved prenatal consultation and coordinated perinatal care to improve clinical outcomes.

Fetal body MRI for fetal and perinatal management

Fetal magnetic resonance imaging (MRI) has become a valuable adjunct to ultrasound (US) in diagnosing fetal abnormalities. This review is intended to highlight the contribution of MRI in parental counselling and perinatal treatment. A state-of-the-art fetal MRI protocol with experts of maternal-fetal medicine present in the MRI suite allows emphasis on patient-centred care and maximises therapeutic options.

Limb body wall complex complicating a dichorionic diamniotic twin pregnancy: MRI for demonstration of fetal morphology

Limb body wall complex (LBWC) is a rare, lethal malformation characterised by body wall defects, craniofacial and limb anomalies with or without various other organ anomalies. We report a case of dichorionic diamniotic twin pregnancy discordant for LBWC, diagnosed by ultrasound (US) and confirmed by MRI at 21 weeks' gestation, managed expectantly and delivered at 35 weeks by emergency caesarean section with a favourable outcome of the unaffected twin. The anomalous twin, who died soon after birth, had a sizeable thoracoabdominal wall defect, eviscerated liver and bowel loops attached to the placenta, short cord, ectopia cordis, lung hypoplasia, kyphoscoliosis, right upper limb amelia and left clubfoot with polydactyly. MRI helps to demonstrate the fetal morphology better when there are limitations to the US due to unfavourable fetal position, multifetal gestation, maternal obesity or reduced liquor. In twin pregnancies, the management will depend on ensuring the survival of the unaffected twin.

Rapidly involuting congenital hemangioma of the liver in a newborn with incomplete Pentalogy of Cantrell: description of a new association

The perinatal management of newborns with giant omphaloceles requires careful suspicion concerning ‘unexpected’ associated malformations. We describe a newborn with a combination of incomplete Pentalogy of Cantrell consisting of giant omphalocele, anterior congenital diaphragmatic hernia (CDH) and pericardial absence complicated by a hepatic rapidly involuting congenital hemangioma (RICH). A giant omphalocele was detected prenatally. Postnatally, staged closure of the omphalocele was planned. A mass of the liver was noted and (mis-)taken for a hematoma. In the further course, the baby developed cardiorespiratory insufficiency due to a central CDH which was excised. Subsequently, staged closure of the omphalocele became impossible. Specific workup revealed a mass in the left liver lobe. The mass was resected and the abdominal wall defect repaired. Histology confirmed the diagnosis of an RICH. The surgical treatment of newborns with giant omphaloceles requires a multidisciplinary neonatal support and an elaborate pediatric surgical armamentarium to cope with additional malformations.

Omphalocele-What should we tell the prospective parents?

An omphalocele is a congenital defect in the abdominal wall characterized by absent abdominal muscles, fascia, and skin. The characteristic ultrasound appearance includes a midline defect with herniation of abdominal contents into the base of the umbilical cord. Other anatomic abnormalities are seen in approximately 50% of cases, most notably cardiac defects (19%-32%). Approximately, 50% of cases are associated with genetic and multiple malformation syndromes including trisomy 13/18, pentalogy of Cantrell and Beckwith-Wiedemann syndrome. Therefore, a thorough evaluation is recommended, including detailed anatomic survey, fetal echocardiogram, genetic counseling, and prenatal diagnostic testing. Overall prognosis depends on the size of the omphalocele, genetic studies, and associated anomalies. Early prenatal diagnosis remains important in order to provide parental counseling and assist in pregnancy management. Delivery should occur at a tertiary care center. Timing and mode of delivery should be based on standard obstetric indications with cesarean delivery reserved for large omphalocele (>5 cm) or those that involve the fetal liver. Neonatal management involves either primary or staged reduction, both of which can be associated with a prolonged neonatal hospitalization.

Is fetal magnetic resonance imaging volumetry of eventrated organs in gastroschisis predictive for surgical treatment?

BACKGROUND

Fetal MRI is increasingly used in congenital abdominal wall defects. In gastroschisis, the role of fetal MRI in surgical therapy is poorly understood. Currently, the type of repair is determined primarily by clinical presentation and institutional preference.

OBJECTIVE

To evaluate the feasibility of fetal MRI volumetry in gastroschisis treatment.

MATERIALS AND METHODS

We included 22 cases of gastroschisis in this retrospective single-center study. Routine fetal MRI scans were acquired between Jan. 1, 2006, and July 1, 2018, at gestational ages of 19-34 postmenstrual weeks. Fetal-MRI-based manual segmentation and volumetry were performed utilizing steady-state free precision and T2-weighted sequences. Acquired parameters included intraabdominal volume, eventrated organ volume and total fetal body volume, and we calculated a volume ratio between eventrated organ volume and intraabdominal volume (E/I ratio).

RESULTS

Primary closure was conducted in 13 cases and silo bag treatment with delayed closure in 9 cases. Prenatal MRI volumetry showed a significantly higher E/I ratio in patients with silo bag treatment with delayed closure (mean [M]=0.34; 95% confidence interval [CI] 0.30, 0.40) than in primary closure (M=0.23, 95% CI 0.19, 0.27; P=0.004). We propose a volume ratio cutoff value of 0.27 for predicting silo bag treatment.

CONCLUSION

Fetal MRI predicted silo bag treatment in patients with gastroschisis in 90% of the cases in our cohort and might facilitate prenatal counseling and treatment planning.

Imaging findings in association with altered maternal alpha-fetoprotein levels during pregnancy

Maternal serum alpha-fetoprotein is a valuable laboratory test used in pregnant women as an indicator to detect certain clinical abnormalities. These can be grouped into four main categories: fetal factors, pregnancy complications, placental abnormalities, and maternal factors. Imaging is an invaluable tool to investigate the various etiologies leading to altered maternal serum alpha-fetoprotein. By reading this article, the radiologist, sonologist, or other health care practitioner should be able to define the probable pathology leading to the laboratory detected abnormal maternal serum levels, thus helping the clinician to appropriately manage the pregnancy and counsel the patient.

Key anatomic findings on fetal ultrasound and MRI in the prenatal diagnosis of bladder and cloacal exstrophy

INTRODUCTION

Prenatal determination of bladder exstrophy (BE) or cloacal exstrophy (CE), known also as the omphalocele-exstrophy-imperforate anus-spinal anomaly complex (OEIS), is challenging. Distinguishing between BE and CE is important because children with CE have many more challenges initially and during their lifetime. An accurate diagnosis is critical when counselling expectant parents. We hypothesized that there are key imaging features that can distinguish BE from CE, and that there are areas of diagnostic concordance and discordance between fetal ultrasound (fUS) and fetal MRI (fMRI) among these entities.

MATERIALS AND METHODS

We queried a single institutional IRB-approved registry of children with BE and CE to identify those with accessible fetal imaging from 2000 to 2018, and formal interpretations were collected. Two pediatric radiologists performed independent retrospective blinded review of the images. Criteria evaluated included: genitalia, kidneys, bowel appearance, presence of anal dimple, location of insertion of umbilical cord into the abdomen relative to the abdominal wall defect, umbilical vessels, bladder protuberance, presence of omphalocele, and spine/neural cord abnormalities. We evaluated concordance between radiologic interpretations and postnatal diagnosis, as well as between specific findings in the two diagnostic modalities.

RESULTS

Twenty-one infants born between 2000 and 2018 with BE or CE had fetal imaging for review: 15 had both fUS and fMRI, 2 had fUS alone, and 4 fMRI alone. There was 100% concordance between fUS and fMRI in evaluating kidneys, presence of anal dimple, location of abdominal insertion of umbilical cord relative to the defect, number of umbilical vessels, and spine abnormalities/level of neural cord termination. The following discrepancies were observed: 1) genitalia and bowel appearance, and bladder protuberance in 1/15 (6.7%); 2) presence of an omphalocele in 2/15 (13.3%). Of the initial radiologic interpretations, 4/17 (23.5%) of fUS and 2/19 (10.5%) of fMRI erroneously were interpreted as on the OEIS spectrum when the post-natal diagnosis was BE. Errors in diagnosis were due to a protuberant bladder plate extending beyond the plane of the abdominal wall with bowel loops posteriorly mimicking an omphalocele. In all of these BE cases, the abdominal wall defect was located inferior to the umbilical cord insertion on the abdominal wall.

CONCLUSION

An everting bladder plate with bowel loops posterior to the plate in classic BE may be misdiagnosed as CE. Identification of the location of umbilical cord insertion relative to the abdominal wall defect, with fetal US or MRI, results in the correct differentiation between BE and CE.

An Algorithmic Approach to Complex Fetal Abdominal Wall Defects

OBJECTIVE. The purpose of this article is to describe the imaging findings associated with complex fetal abdominal wall defects and provide an algorithmic method for arriving at a final diagnosis. CONCLUSION. Fetal ventral abdominal wall defects are a complex group of conditions with a broad spectrum of associated multisystem anomalies and manifestations. Correct characterization and classification of these defects require not only familiarity with imaging findings but also a systematic approach to avoid diagnostic confusion.

Complete and Incomplete Pentalogy of Cantrell

Pentalogy of Cantrell (PC) is a malformation characterized by defects in the ventral abdominal wall, lower sternum, diaphragmatic pericardium, anterior diaphragm associated with omphalocele, thoraco-abdominal ectopia cordis, diaphragmatic hernia, and intracardiac abnormalities. PC is stratified as complete or incomplete and we present both the complete and incomplete forms.

Prenatal diagnosis and management of omphalocele

Omphalocele (exomphalos) is one of the most common abdominal wall defects. The size of the defect and the severity of the associated anomalies determine the overall morbidity and mortality. Routine prenatal screening and diagnosis of the abdominal wall defect and concurrent anomalies is important as it allows for effective prenatal counseling and optimal perinatal management. The purpose of this article is to discuss the approach to prenatal diagnosis and management of omphalocele.