Single contrast upper GI technique

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Single contrast upper GI technique is a method of imaging the esophagus, stomach, and duodenum with fluoroscopy. "Single contrast" refers to imaging with barium or water-soluble contrast only, without the addition of effervescent granules.

Indications

The single contrast upper GI study may be preferred over a double contrast technique when

  • the patient is unable to turn quickly/effectively
    • double contrast technique requires rapid changes in patient position
  • evaluation for postoperative leak after surgery
  • large patient body habitus which would render double contrast technique suboptimal
  • there has been restrictive gastric surgery or there is potential obstruction and distention of the stomach or duodenum would potentially cause a great deal of pain
  • when you plan on performing a small bowel follow through afterward

Contraindications

There are few contraindications. If the patient is aspirating then a very careful and limited study could be performed with barium if necessary, otherwise consider deferring the exam. If evaluation of the esophageal or gastric mucosa is what is clinically desired, then a double contrast upper GI technique is preferred.

Water-soluble contrast should be used when evaluating for postoperative leak.

Procedure

Pre-procedure

The patient should be NPO for the study. Medications with sips of water should be allowed.

Before the exam, briefly interview the patient to see what his or her symptoms are, how long they have been going on, if they have a history of gastro-esophageal reflux, if they have a history of upper abdominal surgery, or if they take NSAIDs chronically.

Equipment
  • fluoroscopic equipment
  • some method of compression (e.g. radiolucent paddle or leaded glove)
  • a 13 mm radio-opaque pill taped to a tongue depressor or some other object of known size that can be used as a measurement device

One of the most important considerations for a single contrast upper GI is the density of the barium or water-soluble contrast. If it is too dense, then the fluoroscopic tube will potentially "burn out" the image and obscure small (and sometimes large!) lesions. You want contrast that's dense enough to see filling defects, but not too dense. Where this optimal density lies is dependent on one's fluoroscopic equipment and available contrast solutions. In general, 40% w/v is not a bad target. Water-soluble contrast (e.g. Gastrografin) should also be diluted to approximately 40% iodine.

Barium often comes in 100% w/v solutions, so a way to get to 40% w/v density is

  • 800 mL of 100% w/v barium added to 1200 mL of water (2000 ml total)

Glucagon is usually not necessary for single contrast studies.

Technique

The following technique is one possible set of images for a single contrast exam. If the exam is for postoperative leak or for evaluation of a known lesion, it can be modified.

  • scout views
    • AP chest
    • AP upper abdomen
    • if for postoperative leak, sometimes a magnified image of the area of surgery / sutures can be helpful

The first set of images are those of an oesophagram / barium swallow but the technique is interrupted so that the stomach is not overfilled.

If the exam is for esophageal symptoms / globus sensation, then consider starting with lateral rapid sequence / cine images of the pharynx.

Then stand the patient upright in the LPO position, hand him or her a cup of barium to hold with the left hand.

  • LPO rapid sequence of the mid and distal esophagus (with proximal esophagus if possible)
  • RPO if desired to evaluate a potential problem area

Then tilt the table into the horizontal position

  • put the patient in the RAO position and get spot compression images of the duodenum
  • prone position: compression spot images of the gastric antrum (not for postop patients or patients who have a large body habitus.
  • RAO: large field of view cine images of the esophagus to evaluate esophageal motility
    • single swallow per cine series
  • RAO: continuous drinking with magnified spot images of the esophageal barium column
  • right lateral: image(s) of the gastric fundus
  • RPO: image(s) of the upper gastric body and lesser curvature
  • supine: image(s) of the distal stomach
  • LPO: image(s) of the gastric antrum
  • LPO: image(s) of the duodenal bulb

Compression images can be mixed in with these or one can wait until bringing the patient back upright for compression views.

Then tilt the table in the vertical position (patient standing)

  • frontal view: lesser curvature
  • (optional): LPO for antrum and duodenal bulb, RPO for duodenal bulb in profile

In at least one image, get the transverse duodenum with contrast at the duodenal-jejunal junction.

If planning a small bowel follow through, get images of the jejunum at the end of the upper GI portion of the exam.

If the exam is to evaluate post-surgical situations (such as a Roux-en-Y bypass) then the previous set of images should be modified.

Postprocedural care

The patient should be encouraged to stay hydrated and, if using barium, not to be alarmed if white material comes out in future stools.