Neonatal Bowel Disorders: Practical Imaging Algorithm for Trainees and General Radiologists

[Developmental disorders of the gastrointestinal tract]

BACKGROUND

Developmental disorders of the gastrointestinal tract comprise a broad spectrum of congenital malformations of different etiologies and locations from the mouth to the anus.

METHODS

The authors present the most important malformations of the gastrointestinal tract on the basis of basic and current reviews.

RESULTS

Gastrointestinal developmental disorders occur both sporadically and in connection with malformation syndromes. Symptoms are highly variable and range from postnatal emergencies to asymptomatic abnormalities, which may be incidental radiological findings. Prenatal ultrasound examinations can often identify gastrointestinal developmental disorders at an early stage. Here, fetal magnetic resonance imaging can be a useful addition to the diagnostic process. In the first few days of life, simple X‑ray overview images, supplemented by images after the administration of contrast medium, are often sufficient.

CONCLUSION

Many patients with a malformation of the gastrointestinal tract require lifelong medical care, so that not only pediatric radiologists need specific knowledge about this group of diseases.

The performance of ultrasound and upper gastrointestinal study in diagnosing malrotation in children, with or without volvulus

BACKGROUND

Rapid diagnosis is crucial for pediatric patients with midgut volvulus and malrotation to prevent serious complications. While the upper gastrointestinal study (UGIS) is the traditional method, the use of ultrasound (US) is gaining prominence.

OBJECTIVES

To assess the diagnostic sensitivity and specificity of US compared to UGIS for malrotation and midgut volvulus.

METHODS

A cross-sectional study was performed on 68 pediatric patients who underwent US and/or UGIS before surgery for suspected midgut volvulus or malrotation in Kuala Lumpur (PPUKM and HTA), referencing surgical outcomes as the gold standard.

RESULTS

US demonstrated a higher specificity (100%) than UGIS (83%) for diagnosing malrotation, with a slightly lower sensitivity (97% vs. 100%). For midgut volvulus, US surpassed UGIS in sensitivity (92.9% vs. 66.7%) while maintaining comparable specificity. The SMA/SMV criteria showed better sensitivity (91.1%) than the D3 assessment (78.9%) on US, though both had high specificity.

CONCLUSION

US is equivalent to UGIS for identifying malrotation and is more sensitive for detecting midgut volvulus, supporting its use as a primary diagnostic tool. The study advocates for combined US and UGIS when either yields inconclusive results, optimizing diagnostic precision for these conditions.

Ultrasound imaging of bowel obstruction in neonates

Bowel obstruction (BO) in children has a wide differential diagnosis, ranging from non-urgent conditions to surgical emergencies. Abdominal radiographs are most often used as the first imaging modality for the evaluation of obstruction. However, for some indications, ultrasound can be the primary imaging modality. Therefore, it is incumbent on radiologists to recognize the types of bowel obstruction that can be recognized with US. Key sonographic features of BO include differential dilation of bowel loops, bowel wall thickening, and free fluid. "Do Not Miss" findings that indicate need for emergent treatment include volvulus, pneumoperitoneum, and/or signs of ischemia (bowel wall thinning and/or absent perfusion). The aim of this pictorial essay is to provide guidance on the sonographic technique and findings that enable identification of BO on US. Examples of neonatal BO on US, including common and less frequently encountered etiologies, are illustrated in this pictorial essay.

Imaging Features of Neonatal Bowel Obstruction

Radiologic evaluation of neonatal bowel obstruction is challenging owing to the overlapping clinical features and imaging appearances of the most common differential diagnoses. The key to providing an appropriate differential diagnosis comes from a combination of the patient's gestational age, clinical features, and imaging findings. While assessment of radiographs can confirm bowel obstruction and indicate whether it is likely proximal or distal, additional findings at upper or lower gastrointestinal contrast study together with use of US are important in providing an appropriate differential diagnosis. The authors provide an in-depth assessment of the appearances of the most common differential diagnoses of proximal and distal neonatal bowel obstruction at abdominal radiography and upper and lower gastrointestinal contrast studies. These are divided into imaging patterns and their associated differential diagnoses on the basis of abdominal radiographic findings. These findings include esophageal atresia variants including the "single bubble," "double bubble," and "triple bubble" and distal bowel obstruction involving the small and large bowel. Entities discussed include esophageal atresia, hypertrophic pyloric stenosis, pyloric atresia, duodenal atresia, duodenal web, malrotation with midgut volvulus, jejunal atresia, ileal atresia, meconium ileus, segmental volvulus, internal hernia, colonic atresia, Hirschsprung disease, and functional immaturity of the large bowel. The authors include the advantages of abdominal US in this algorithm, particularly for hypertrophic pyloric stenosis, duodenal web, malrotation with midgut volvulus, and segmental volvulus. ©RSNA, 2023 Online supplemental material is available for this article. Quiz questions for this article are available through the Online Learning Center.

Small-bowel atresias: a case series with review of the disease and imaging findings

Small-bowel atresias are among the most common causes of intestinal obstruction in newborns, and they often require urgent surgical treatment. Imaging techniques play a very important role in their diagnosis, which is often suspected on prenatal obstetric ultrasound and confirmed on postnatal plain-film X-rays. Abdominal ultrasound's lack of ionizing radiation, wide availability, low cost, and high resolution is making this technique increasingly important in confirming atresias and in detecting possible complications in newborns. This review analyzes a series of cases seen at our center. It summarizes the different types of small-bowel atresias, focusing on the clinical presentation, imaging findings on different modalities, presence of associated disease, management, clinical course, and outcomes.

Bedside upper gastrointestinal series in the neonatal intensive care unit

BACKGROUND

In neonatal intensive care unit (NICU) patients with intubation status, fluoroscopic evaluation for the bowel is limited. This study was to evaluate the utility of bedside upper gastrointestinal (UGI) series with delayed radiographs (DR) for assessing duodenojejunal junction (DJJ) and small bowel passage in NICU patients with nonspecific bowel ultrasonography and contrast enema findings.

METHODS

We reviewed clinical and imaging data for bedside UGI with DR of NICU patients from 2014 to 2019. Five abdominal radiographs were obtained at fixed time intervals of immediately after, 1 min, 5 min, 1 h, and 2 h following the administration of 5 cc/kg isotonic water-soluble contrast agent via the nasogastric tube.

RESULTS

Twenty bedside UGI with DR were performed in 17 patients (weight range: 520-3620 g, age range: 0-4 months). Confidence identifying the DJJ was either good (n = 7) or equivocal (n = 8) at immediate or 1 min radiographs. The DJJ could not be evaluated in five from four delayed passage (including two meconium plug syndrome and one gastric volvulus) and one inadequate timing. There was only one case of intestinal malrotation, which was not detected on ultrasonography, but detected at the first UGI examination with good DJJ confidence.

CONCLUSIONS

Bedside UGI with DR can evaluate intestinal malrotation using immediate and 1 min delay and small bowel passage using 1 and 2 h delay images in NICU patients with nonspecific ultrasonographic and contrast enema findings. The majority with delayed contrast passages can have bowel pathology. Because of a small number of patients in this study, further studies with more infants are needed.

ACR Appropriateness Criteria® Vomiting in Infants

Vomiting in infants under the age of 3 months is one of the most common reasons for parents to seek care from their doctor or present to an emergency room. The imaging workup that ensues is dependent on several factors: age at onset, days versus weeks after birth, quality of emesis, bilious or nonbilious vomiting, and the initial findings on plain radiograph, suspected proximal versus distal bowel obstruction. The purpose of these guidelines is to inform the clinician, based on current evidence, what is the next highest yield and most appropriate imaging study to pursue a diagnosis. The goal is rapid and accurate arrival at a plan for treatment, whether surgical or nonsurgical. The following modalities are discussed for each variant of the symptom: plain radiography, fluoroscopic upper gastrointestinal series, fluoroscopic contrast enema, ultrasound of the abdomen, nuclear medicine gastroesophageal reflux scan. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.