How is an upper gastrointestinal (UGI) series performed in a 9‑month‑old infant?

How an Upper GI Series is Performed in a 9-Month-Old Infant

An upper GI series in a 9-month-old infant is performed using fluoroscopy with oral contrast material (water-soluble or barium) administered through a bottle, nasogastric tube, or direct oral feeding, with sequential imaging to visualize the esophagus, stomach, duodenum, and proximal small bowel. 1

Procedural Technique

Contrast Administration

• Contrast agent: Water-soluble iodinated contrast or barium sulfate is used
• Volume: Typically 5 cc/kg of body weight 2
• Delivery method:
  • For cooperative infants: Administered via bottle or direct oral feeding
  • For critically ill or intubated infants: Given through nasogastric tube 3, 2
  • The infant should be NPO (nothing by mouth) for 2-4 hours prior to the examination to ensure adequate gastric emptying

Imaging Protocol

The examination follows a systematic fluoroscopic evaluation:

• Initial imaging: Real-time fluoroscopy begins immediately after contrast administration

• Sequential views: Images are obtained at specific intervals:

  • Immediate post-administration
  • 1 minute delay
  • 5 minutes delay
  • 1 hour delay (if evaluating for delayed passage)
  • 2 hours delay (if assessing small bowel transit) 2

• Standard projections: Multiple views are obtained including:

  • Anteroposterior (AP) views
  • Lateral views
  • Right anterior oblique (RAO) views to best visualize the duodenojejunal junction (DJJ)

Key Anatomic Landmarks Assessed

The radiologist specifically evaluates:

• Esophageal anatomy and motility
• Gastric position and emptying
• Duodenal sweep and C-loop configuration
• Position of the duodenojejunal junction (should be at or to the left of the left pedicle of the vertebral body and at the level of the pylorus)
• Proximal jejunal course

Clinical Context for a 9-Month-Old

At 9 months of age, the primary indications for UGI series include:

• Bilious vomiting: UGI is the gold standard to evaluate for malrotation with potential midgut volvulus—a surgical emergency 1, 4
• Anatomic abnormalities: To exclude structural causes of vomiting such as duodenal stenosis, annular pancreas, or gastric outlet obstruction 1
• Pre-surgical evaluation: In patients requiring gastrostomy tube placement or fundoplication, UGI identifies anatomic abnormalities that need surgical correction 1

Important Caveats

Gastroesophageal reflux (GER) evaluation: UGI series is NOT recommended for diagnosing reflux in otherwise healthy infants. The sensitivity and specificity are poor (31-86% and 21-83% respectively), with high false-negative and false-positive rates due to the brief examination duration 1. UGI is useful only to exclude anatomic causes that mimic reflux symptoms.

Pyloric stenosis: If hypertrophic pyloric stenosis is suspected in this age group (though uncommon at 9 months), ultrasound is the preferred initial imaging modality, not UGI 1

Radiation Considerations

• Pediatric patients are at higher risk from radiation exposure due to organ sensitivity and longer life expectancy 1
• The presence of contrast media can actually reduce organ absorbed doses by up to 50% through selective x-ray beam absorption 5
• Fluoroscopy time should be minimized using pulsed fluoroscopy and last-image-hold techniques
• The relative radiation level (RRL) for pediatric UGI is lower than adult protocols but still requires ALARA (as low as reasonably achievable) principles

Alternative and Adjunctive Techniques

Bedside UGI: For critically ill, low birth weight, or intubated infants in the NICU, bedside portable UGI with delayed radiographs can be performed to minimize risks of transport (hypothermia, line dislodgement) 3, 2. This technique has 78% diagnostic accuracy for identifying the DJJ position.

Saline-aided ultrasound: Recent evidence shows saline-aided ultrasound (saline administered via nasogastric tube during real-time ultrasound) has comparable or superior diagnostic performance to UGI for detecting upper GI obstruction (94.7% vs 89.5% accuracy), with the advantage of no radiation exposure 6. However, this requires specialized expertise and is not yet widely adopted as standard practice.

Ultrasound adjuncts: When UGI findings are equivocal, ultrasound can identify the "whirlpool sign" specific for midgut volvulus or assess the relationship of the superior mesenteric artery and vein 1

Diagnostic Pitfalls to Avoid

• Inadequate timing: Radiographs obtained too early or too late may miss the DJJ 3
• Patient rotation: Improper positioning can create false impressions of DJJ location
• Bowel distention: Pre-existing bowel gas or distention can obscure contrast visualization 3
• Suboptimal tube position: Nasogastric tube tip should be in the gastric body for adequate contrast delivery 3
• Inconclusive studies: Up to 15% of UGI studies may be inconclusive, particularly with faint opacification or overlapping bowel loops 7. In these cases, adjunctive ultrasound or repeat UGI with modified technique may be necessary.