RAD-CONTRAST (GIT)

Special Radiographic Examinations

Gastro-Intestinal Tract

Introduction

Radiographic examinations of the gastro-intestinal (GI) tract are important diagnostic procedures in medical imaging. They allow visualization of the hollow organs of the digestive system by using contrast media and special positioning techniques. Although modern modalities such as ultrasound, CT, and MRI are widely used today, conventional GI radiography continues to play an essential role, especially in functional studies and in areas with limited access to advanced technology.

This report discusses the indications, contraindications, patient preparation, contrast media, types of examinations, and positioning modifications applied in special radiographic studies of the gastro-intestinal tract.

1. Indications and Contraindications

Indications

Radiographic studies of the GI tract are performed to:

  • Detect structural abnormalities such as strictures, ulcers, diverticula, tumors, and polyps.

  • Assess functional disorders, including swallowing problems, reflux, and abnormal motility.

  • Evaluate obstruction in the esophagus, stomach, small bowel, or colon.

  • Investigate biliary system pathology, such as stones, narrowing, or dilatation of ducts.

Contraindications

Although generally safe, these examinations are contraindicated in:

  • Suspected perforation, since barium leakage into the peritoneal cavity may cause peritonitis.

  • Severe allergy to iodinated contrast media (for cases requiring water-soluble contrast).

  • Unstable or critically ill patients, unless the procedure is urgently required.

  • High aspiration risk, especially in patients with impaired swallowing.

2. Preparation of the Patient

Successful GI imaging depends on proper preparation to ensure clarity of images.

  1. Dietary restriction – Patients are usually placed on a low-residue diet one to two days before the procedure to minimize gas and stool.

  2. Fasting (NPO) – No food or drink for 8–12 hours before the study to keep the stomach and intestines empty.

  3. Bowel cleansing – Laxatives or cleansing enemas are required before barium enema studies to remove fecal matter that may obscure findings.

  4. Patient education – It is important to explain the procedure, the taste and texture of contrast medium, and possible side effects (such as constipation after barium). A calm and cooperative patient leads to better results.

3. Contrast Media

Contrast media are used to make hollow structures of the GI tract visible under X-ray.

  • Barium sulfate

    • Most commonly used.

    • Provides excellent coating of the mucosa, highlighting fine details.

    • Safe for the GI tract but must not be used if perforation is suspected.

  • Water-soluble iodinated contrast

    • Used as an alternative when perforation, obstruction, or fistula is suspected, or when imaging is performed after surgery.

    • Less coating ability than barium but safer in leakage situations.

4. Types of Examinations

4.1 Sialography

  • Examines salivary glands and ducts (parotid, submandibular).

  • Indications: stones (sialolithiasis), chronic infection, tumors, ductal obstruction.

  • Technique: injection of water-soluble iodinated contrast into the duct, followed by X-ray imaging.

4.2 Pharyngography

  • Evaluates the pharynx and swallowing mechanism.

  • Indications: aspiration, strictures, tumors, and neuromuscular swallowing disorders.

  • Often performed with videofluoroscopy to assess dynamic swallowing.

4.3 Esophagography (Barium Swallow)

  • Visualizes the esophagus.

  • Indications: strictures, diverticula, varices, hiatal hernia, gastroesophageal reflux, carcinoma.

  • Technique: patient swallows barium while fluoroscopy records movement.

  • Positioning: RAO (Right Anterior Oblique) best for unobstructed view.

4.4 Upper Gastro-Intestinal Series (UGIS) / Barium Meal

  • Studies esophagus, stomach, and duodenum.

  • Indications: peptic ulcer disease, gastritis, tumors, hiatal hernia, pyloric stenosis.

  • Technique: sequential imaging as barium passes from esophagus to duodenum.

  • Positioning:

    • RAO – fills pyloric region.

    • Supine – fills gastric fundus.

4.5 Small Intestinal Series

  • Evaluates small intestine by following barium transit.

  • Indications: Crohn’s disease, obstruction, malabsorption, tumors.

  • Technique: may take 2–6 hours depending on intestinal transit time.

4.6 Barium Enema (Lower GI)

  • Visualizes colon and rectum.

  • Indications: polyps, cancer, diverticulosis, inflammatory bowel disease, obstruction.

  • Requires very clean bowel for accurate results.

  • Techniques:

    • Single contrast – only barium.

    • Double contrast – barium + air for mucosal detail.

4.7 Biliary System

4.7.1 Cholecystography & Cholangiography

  • Imaging of gallbladder and bile ducts.

  • Rarely performed today due to ultrasound and CT.

4.7.2 Operative Cholangiography

  • Performed during surgery to visualize bile ducts for stones or leaks.

4.7.3 T-Tube Cholangiography

  • Post-operative evaluation through a tube left in the bile duct after surgery.

4.7.4 Percutaneous Transhepatic Cholangiography (PTC)

  • Direct puncture of the liver to access bile ducts.

  • Used when endoscopic methods are not possible.

4.7.5 Endoscopic Retrograde Cholangio-Pancreatography (ERCP)

  • Combines endoscopy and fluoroscopy to examine bile ducts and pancreatic ducts.

  • Indications: stones, strictures, tumors, pancreatitis.

  • Can also allow therapeutic interventions such as stone removal.

5. Modifications of Positioning

Correct positioning is vital for accurate diagnosis.

  • Trendelenburg – demonstrates hiatal hernia by moving abdominal contents upward.

  • RAO esophagus – avoids superimposition of spine on esophagus.

  • Decubitus colon – shows air-fluid levels and mucosal lesions.

  • Valsalva maneuver – increases intrathoracic pressure to demonstrate reflux or varices.

  • Prone and erect positions – aid in demonstrating barium distribution and small bowel separation.

Conclusion

Special radiographic examinations of the gastro-intestinal tract provide valuable diagnostic information in detecting both structural and functional abnormalities. While modern imaging modalities have supplemented many traditional techniques, procedures such as barium swallow, upper GI series, and barium enema remain useful in certain clinical settings.

The success of these examinations relies on careful patient preparation, proper choice of contrast medium, and precise positioning. Radiographers must have a thorough understanding of the principles and applications of each study to ensure accurate results and patient safety.