Ultrasound imaging of bowel obstruction in infants and children.

We review the etiologies of bowel obstruction in infants and children that can be identified on ultrasound (US) including perforated appendicitis, intussusception, foreign body ingestion, colonic volvulus, intra-abdominal mass lesions, internal hernia, and stricturing inflammatory bowel disease. US can potentially identify the cause of bowel obstruction in these age groups, without the need for additional cross-sectional imaging, and can aid in patient management including interventional and surgical planning. Hence, it is important to be familiar with the sonographic imaging findings of bowel obstruction in infants and children.

Body mass index as a predictor of sonographic visualization of the pediatric appendix.

BACKGROUND: Appendicitis is a common condition that is often confirmed with imaging. Ultrasound (US) is recommended as the first radiologic test in the work-up of appendicitis in children. Increased body mass index (BMI) has been implicated as a limiting factor to the sensitivity of US. This has drastic public health ramifications, as pediatric obesity has been increasing at alarming rates. OBJECTIVE: The purpose of this study is to compare age-adjusted BMI z-scores to the frequency of sonographic visualization of the appendix. MATERIALS AND METHODS: A retrospective review of 500 consecutive reports of US exams ordered for appendicitis in patients with a documented BMI was performed. Patients were stratified by BMI z-score based on, and the visualization frequency of the appendix was compared to the BMI z-score group. A logistic regression analysis generated the odds of visualization of the appendix by BMI z-score group. Primary home language, ethnicity, sex and insurance status were included in the logistic regression model to assess these characteristics as potential effect modifiers. RESULTS: Of the 500 patients, 52.4% were male, 56.4% were Hispanic and 62.0% had government insurance. BMI z-score distribution groups were as follows: 4.2% were <-2, 8.0% were -2 to -1, 49.8% were -1 to 1, 26.4% were 1 to 2 and 11.6% were >2. The visualization frequency was 61.1% for boys and 46.2% for girls (P<0.05). Visualization frequency by BMI z-score group was as follows: 85.7% for <2, 72.5% for -2 to -1, 57.4% for -1 to 1, 47.7% for 1 to 2 and 29.3% for >2. Children with a BMI z-score greater than 2 were less likely to have a US with visualization of the appendix compared to children with a BMI z-score between -1 and 1 (adjusted odds ratio [aOR]: 0.21, 95% CI: 0.11-0.40, P<0.0001). Boys were more likely than girls to have a US with visualization of the appendix (aOR: 1.90, 95% CI: 1.29-2.80, P=0.001). There was no effect from insurance status, ethnicity or primary home language. CONCLUSION: Findings show that as the BMI z-score increased, sonographic visualization of the appendix decreased even after adjusting for demographic differences. These findings have implications for pediatric radiology practice in light of the worsening obesity epidemic.

Impact of Focused Abdominal Ultrasound Utilization on Outcomes for Children With Midgut Volvulus.

BACKGROUND: Ultrasound (US) is gaining acceptance for the evaluation of midgut volvulus in children. However, its impact on clinical outcomes is unknown. We aim to determine whether using US as a first-line modality changes imaging mobilization, time to surgery and re-feeding, length of stay, and frequency of bowel necrosis, short bowel syndrome, and death. METHODS: An IRB-approved retrospective cohort study was performed at a tertiary pediatric institution. Eighty children with surgically confirmed midgut volvulus from 2014 to 2021 were compared before and after implementation of US as first-line imaging and based on the modality used to diagnose midgut volvulus. RESULTS: Outcomes were not statistically different pre- versus post-implementation. Compared with patients who had UGI only, those who had US only or both had significantly quicker imaging mobilization (median: -33 min; 95% CI: -61.2, -4.8; p = 0.023 and median: -31 min; 95% CI: -58.5, -3.6; p = 0.028 respectively). Patients with US only were less likely to have bowel necrosis compared with those who had UGI only (9.1% versus 43.8%, p = 0.042). Patients who had US only or both were less likely to develop short bowel syndrome compared to UGI only (4.8% US only, 0% both, 40% UGI only; p = 0.027 for US only, p = 0.005 for both). CONCLUSIONS: No statistically significant change in outcomes was found after implementation of US as first-line imaging for midgut volvulus. However, patients diagnosed with US only or US in combination with UGI had quicker imaging mobilization and decreased frequency of bowel necrosis and short bowel syndrome. Findings suggest that US has potential to improve patient outcomes. LEVEL OF EVIDENCE: III.

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.