Barium Meal and Follow-Through

The barium meal is a fluoroscopic study of the oesophagus, stomach and duodenum after drinking barium sulphate suspension (double contrast technique with effervescent granules and a smooth muscle relaxant such as hyoscine butylbromide or glucagon), with spot films in various positions.

In the follow through, serial films are taken every 20 to 30 minutes as the barium passes through the small bowel to the caecum (30 minutes to 4 hours, depending on transit) and the terminal ileum is shown with compression or a targeted spot film. The effective dose is about 3 to 6 mSv.

Upper gastrointestinal endoscopy has replaced the barium meal for most patients, because it allows direct vision and biopsy, and MR enterography and CT enterography have replaced the small bowel follow through for most small bowel disease because they show the bowel wall, mesentery and extramural disease.

The examination is still used where endoscopy or cross-sectional imaging is not available, when endoscopy is declined or not possible (frail patients, patients with severe lung disease or on anticoagulation), and for functional assessments, such as gastric outlet obstruction, post-surgical anatomy and transit time.

In infants, the upper gastrointestinal contrast study (a barium or water soluble meal) is the key test for malrotation with volvulus and for gastric outlet obstruction, since time to diagnosis alters the survival of the bowel.

Indications. Dyspepsia or upper abdominal pain, vomiting or early satiety when endoscopy is not available or declined. Suspected gastric outlet obstruction (peptic stricture, tumour, pyloric stenosis in infants if ultrasound is inconclusive). Suspected gastric or duodenal ulcer or tumour.

Assessment of hiatus hernia, gastric volvulus and post-operative anatomy and complications (anastomotic stricture, gastroparesis). Bilious vomiting in a neonate or infant (malrotation, duodenal obstruction).

Small bowel follow through for suspected small bowel disease (Crohn disease, tuberculosis, tumours, strictures, fistulae, malabsorption and adhesions) where MR or CT enterography is unavailable. Obscure gastrointestinal bleeding or abdominal pain with negative endoscopy where cross-sectional tests are unavailable. Not for routine investigation of dyspepsia, or when endoscopy is readily available.

Contraindications and precautions. Suspected perforation or recent upper gastrointestinal surgery with possible leak: use water soluble contrast. Complete large bowel obstruction or severe constipation: barium may impact.

Smooth muscle relaxant is avoided in patients with glaucoma (narrow angle), prostatic obstruction, tachyarrhythmias and myasthenia (hyoscine butylbromide), and glucagon is avoided in phaeochromocytoma, insulinoma and known allergy. Pregnancy: avoid.

Fasting for 6 hours (or longer in gastric outlet obstruction) before the study; patients stop antacids, and in gastric outlet obstruction the stomach is aspirated before barium is given.

Preparation and technique. The patient swallows effervescent granules and a small volume of thick, high density barium and rolls on the table to coat the mucosa; spot films are taken in prone, supine, oblique and erect positions.

For the follow through, a thin barium suspension (with or without metoclopramide to speed transit) is given, and films are taken until barium reaches the caecum. In infants, a small volume of contrast is given through a nasogastric tube or by teat, with the baby in a lateral and supine position, to show the position of the duodenojejunal flexure.

Normal appearances. The gastric mucosa shows a fine network (areae gastricae) of 1 to 3 mm, thin folds of under 5 mm in the body that run along the greater curve, and a smooth lesser curve and antrum.

The duodenal cap is triangular, the C-loop curves to the right of the spine, and the duodenojejunal flexure lies to the left of the left pedicle at the level of the duodenal cap (pylorus). In the small bowel, jejunal folds (valvulae conniventes) are thin and feathery (2 to 3 mm), the ileum is smoother, and the calibre is under 3 cm (jejunum) and 2.5 cm (ileum).

Transit through the small bowel takes 1 to 4 hours, and barium reaches the caecum in about 2 hours.

Interpretation.

• Gastric ulcer: a smooth, round or oval niche on the lesser curve, with radiating mucosal folds that reach the crater edge (benign), a surrounding mucosal "collar", and a Hampton line. Malignant ulcers are irregular and lie within a mass, with nodular, clubbed or fused folds that stop short of the edge, and a rolled edge. Healing needs endoscopic confirmation, and every gastric ulcer is biopsied.
• Duodenal ulcer: a niche in the cap, with a deformed, trefoil shaped cap (scarring) and convergent folds; complications include pyloric stenosis.
• Gastric carcinoma: an irregular filling defect or mass, a rigid narrowed stomach (linitis plastica, a "leather bottle" stomach with absent peristalsis), shouldered stricture at the antrum, and a malignant ulcer; lymphoma shows thickened folds or large masses.
• Gastric outlet obstruction: dilated stomach with retained food, delayed emptying (over 6 hours), and a narrowed pyloric channel or antrum (peptic scarring, tumour, extrinsic compression by pancreatic cancer).
• Hypertrophic pyloric stenosis (infants): an elongated, narrowed pyloric canal ("string sign", "double track sign"), a "shoulder" sign of the antrum, and delayed gastric emptying; ultrasound is the first line test.
• Hiatus hernia: stomach lying in the chest; gastric volvulus (organo axial or mesentero axial rotation with two fluid levels in the chest); and gastric diverticula.
• Malrotation: the duodenojejunal flexure lies to the right of the spine or lower than the level of the pylorus, the proximal jejunum on the right, and the duodenum fails to cross the midline. Volvulus appears as a "corkscrew" or "beak" of twisted duodenum and jejunum, with obstruction of barium passage.
• Crohn disease: asymmetric narrowing, fold thickening, nodular and cobblestone mucosa, deep linear ulcers, "string sign" (long, narrow terminal ileal lumen), skip lesions, fistulae to other bowel or skin, separation of loops by mesenteric thickening, and strictures with proximal dilatation.
• Tuberculosis: ileocaecal disease, with a contracted, conical caecum, a patulous ileocaecal valve and a stenosed terminal ileum (Fleischner sign, Stierlin sign), and multiple strictures.
• Small bowel tumours: a filling defect, an annular constriction or an intussusception lead point (adenocarcinoma, lymphoma, carcinoid with kinking and a desmoplastic reaction, and stromal tumours).
• Coeliac disease and malabsorption: dilatation, flocculation and segmentation of barium, fold changes (loss of jejunal folds and jejunisation of the ileum), and intussusception; Whipple disease and giardiasis show non-specific fold thickening.
• Obstruction and adhesions: dilated loops with transition points and delayed transit, and the study is stopped when obstruction is complete.
• Diverticula and blind loops: jejunal diverticulosis and bacterial overgrowth, and Meckel diverticulum (ileal, with a narrow necked pouch; best seen on enteroclysis).
• Parasites: worm infestation (ascariasis) causes linear tubular filling defects and the barium filled gut of the worm.
• Post-operative anatomy: gastrojejunostomy, gastrectomy (anastomotic leak or stricture, afferent loop obstruction), bariatric surgery (band slippage, anastomotic stricture, leaks) with water soluble contrast first.

Critical values and findings needing immediate action.

• Malrotation with midgut volvulus (a corkscrew duodenum or jejunum and failure to cross the midline) in a baby with bilious vomiting: emergency surgery (Ladd procedure), without delay.
• Contrast leak or perforation: stop barium, use water soluble contrast, and call the surgical team for resuscitation and urgent operation.
• Gastric outlet obstruction with vomiting and dehydration: nasogastric decompression, fluid and electrolyte correction (hypochloraemic, hypokalaemic alkalosis), and endoscopy.
• Malignant ulcer, linitis plastica or a mass: urgent endoscopic biopsy and staging.
• Complete small bowel obstruction with strangulation signs: urgent surgical review.
• Gastric volvulus (Borchardt triad of pain, retching without vomiting and inability to pass a nasogastric tube): emergency surgery.
• Aspiration of barium: suction, oxygen and chest film.

Limitations and artefacts.

• Sensitivity for mucosal disease is lower than endoscopy (about 80 to 90% for ulcers and 70 to 80% for early gastric cancer in double contrast studies, less in single contrast), and no biopsy can be taken.
• Poor coating, air bubbles, food, mucus and peristalsis mimic or hide lesions; folds look thickened when the stomach is not distended; a relaxant and good technique reduce errors.
• Follow through has limited sensitivity for subtle small bowel disease, especially in the pelvic ileum where overlapping loops hide abnormalities; compression films, enteroclysis (barium through a nasojejunal tube) or MR and CT enterography increase sensitivity but add dose or need equipment.
• Barium dilution in the distal small bowel and poor transit produce non-diagnostic studies, and metoclopramide or a repeat film after a delay may help.
• Extramural disease (mesentery, nodes, abscess, vascular disease) is not shown; CT or MR enterography is needed.
• Transit time varies widely, and barium retained for more than 6 hours in the stomach is abnormal, but fasting and medication affect results.
• Radiation dose is moderate and cumulative in young patients with Crohn disease, who should be followed with MR enterography or ultrasound.
• Barium can obscure later CT and interfere with endoscopy if not cleared.

Special groups.

• Neonates and infants: upper gastrointestinal contrast studies are the test for malrotation and duodenal obstruction, with the baby in the lateral position, using a small volume of contrast; ultrasound shows pyloric stenosis and the superior mesenteric vessel relationship.
• Patients with Crohn disease: MR enterography and ultrasound avoid cumulative radiation dose.
• Older adults: gastric cancer, gastric outlet obstruction, hiatus hernia and small bowel obstruction from adhesions or tumour.
• Patients with previous surgery: contrast studies show anatomy and complications that endoscopy may not reach.
• Pregnancy: avoid.
• Regions: peptic ulcer disease with Helicobacter pylori is common, gastric cancer is frequent in East Asia and parts of Africa, small bowel tuberculosis, ascariasis and hookworm are seen in endemic areas, and barium studies remain the main upper gastrointestinal imaging in settings without endoscopy.

Follow up tests. Upper gastrointestinal endoscopy with biopsy, Helicobacter pylori testing, CT or MR enterography for small bowel disease, capsule endoscopy for obscure bleeding (after excluding stricture), colonoscopy and ileoscopy with biopsy for Crohn disease and tuberculosis, CT for staging, ultrasound (pyloric stenosis, malrotation), faecal calprotectin, coeliac serology,

full blood count and iron studies, stool microscopy for parasites, and referral to gastroenterology or surgery.