Standardization of common bile duct size using ultrasound in pediatric patients

Gastrointestinal and Biliary Point-of-Care Ultrasound

Point-of-care ultrasound has been shown to have excellent diagnostic accuracy for a variety of gastrointestinal and biliary pathologies. This review explores the evidence and scanning techniques for hypertrophic pyloric stenosis, intussusception, appendicitis, small bowel obstruction, diverticulitis, hernias, pneumoperitoneum, and biliary pathology.

Normal morphometry of the biliary tree in pediatric and adult populations: A systematic review and meta-analysis

PURPOSE

This study aimed to characterise the normal morphometry of the biliary tree in pediatric and adult populations, through a systematic review and meta-analysis.

METHODS

This study, conducted using the PRISMA guidelines and registered with PROSPERO, searched MEDLINE, EMBASE, SCOPUS and Web of Science databases up to October 2022, and updated to August 2023. Studies that reported extractable data on diameter and length of the right, left and common hepatic ducts (LHD, RHD and CHD), and common bile duct (CBD) were included. Quality of the included studies were assessed using the Anatomical Quality Assessment (AQUA) tool. Statistical analysis included subgroup analyses according to sex, age, geographical location, and imaging modality.

RESULTS

In total, 60 studies were included, of which 44 studies reported adequate data for meta-analysis on 23,796 subjects. Overall, the pooled mean diameter of the CBD was 4.69 mm (95 % CI: 4.28-5.11). Significant differences were found between pediatric (1.32 mm, 95 % CI: 1.03-1.61) and adult (4.97 mm, 95 % CI: 4.67-5.27) subjects, as well as US (3.82 mm, 95 % CI: 3.15-4.49) and other imaging modalities, including MRI (6.21 mm, 95 % CI: 4.85-7.57) and ERCP (7.24 mm, 95 % CI: 6.08-8.40). The CBD diameter measured significantly larger distally (5.20 mm, 95 % CI: 4.60-5.80) than proximally (4.01 mm, 95 % CI: 3.51-4.51).

CONCLUSIONS

The results obtained from this evidence-based study may guide the establishment of standardised reference values and ranges of the normal biliary tree in pediatric and adult populations and aid clinical understanding.

Magnetic resonance imaging following the demonstration of a normal common bile duct on ultrasound in children with suspected choledocholithiasis: what is the benefit?

BACKGROUND

The role of MRI in evaluating children with an in situ gallbladder and suspected choledocholithiasis following a negative or inconclusive US is unclear.

OBJECTIVE

To determine whether MRI benefits children with suspected choledocholithiasis and a normal common bile duct (CBD) without stones on US.

MATERIALS AND METHODS

We conducted a retrospective 10-year review of paired US and MRI (within 10 days) in children 18 years or younger with suspected choledocholithiasis. With MRI as a reference standard, two reviewers independently evaluated the images for CBD diameter, choledocholithiasis, cholelithiasis and pancreatic edema. Serum lipase was recorded. We calculated exact binomial confidence limits for test positive predictive values (PPVs) and negative predictive values (NPVs) using R library epiR.

RESULTS

Of 87 patients (46 female, 41 male; mean age 14 years, standard deviation [SD] 4.6 years; mean interval between US and MRI 1.6 days, SD 1.8 days), 55% (48/87) had true-negative US, without CBD dilation/stones confirmed on MRI; 5% (4/87) had false-positive US showing CBD dilatation without stones, not confirmed on MRI; 33% (29/87) had true-positive US, with MRI confirming CBD dilatation; and 7% (6/87) had false-negative US, where MRI revealed CBD stones without dilatation (2 patients) and CBD dilatation with or without stones (4 patients). Patients with false-negative US had persistent or worsening symptoms, pancreatitis or SCD. The overall US false-negative rate was 17% (6/35). Normal-caliber CBD on US without stones had an NPV of 89% (48/54, 95% confidence interval: 0.77-0.96).

CONCLUSION

MRI adds little information in children with a sonographically normal CBD except in the setting of pancreatitis or worsening clinical symptoms. Further evaluation is warranted in children with elevated risk of stone disease.