Cholegraphy and Contrast Agents

Cholegraphy

• A general term for radiologic exam of the biliary tract using radiopaque contrast agents (C.A.)
• Cholecystangiography or cholecystocholangiography: refers to the examination of the gallbladder and bile ducts
• Cholecystography: specifically for the gallbladder
• Cholangiography: specifically for the bile ducts

Administration of C.A

• Oral: C.A. is taken orally
• IV: Injection of C.A. directly into the vein, either as a single bolus or drip infusion
• Direct injection into the ducts:
  • Percutaneous transhepatic puncture: going through the liver
  • During biliary tract surgery: either during or immediately after surgery
  • Through an indwelling drainage tube: post-operative, delayed or T-tube

Methods of Examination

• Classified based on:
  • Route of entry for contrast media
  • Portion of the biliary tract examined

Route of C.A

• Oral: C.A. passes through the intestines and into the liver via the portal veins
• IV: C.A. travels in the bloodstream and is excreted with bile, reaching the gallbladder via the biliary system

Purposes of Cholegraphy

• Assess liver function: ability to remove C.A. from the blood and excrete it with bile
• Determine the patency (openness) and condition of the biliary ducts
• Evaluate gallbladder concentrating and emptying capabilities
• Identify calculi (stones):
  • Pure cholesterol: appears black (50-60% of stones)
  • Calcified: appears white (10-15%)

Oral Cholecystography

• Administration: 4-6 tablets or capsules taken the evening before the exam
• Alternative name: Cholecystopaques
• Contraindications:
  • Advanced hepatorenal disease (severe jaundice, acute/chronic liver failure, renal failure, hepatocellular disease)
  • Active gastrointestinal disease (vomiting, severe diarrhea, malabsorption syndrome)
  • Hypersensitivity to iodine-containing compounds
  • Pregnancy

Indications for Cholegraphy

• Choledocholethiasis (stones in the common bile duct)
• Cholelithiasis (gallstones)
• Milk calcium bile
• Cholecystitis (inflammation of the gallbladder)
• Neoplasms (tumors)
• Biliary stenosis (narrowing of the bile ducts)
• Congenital anomalies (birth defects)

Patient Preparation for Oral Cholecystography

• Dietary: Start a fat-free diet 1-2 days before the exam; Eat fatty foods the day before the exam at noon
• Laxatives: Avoid 24 hours before the exam
• Light evening meal: No fat or fried foods
• NPO (nothing by mouth): Before the exam
• C.A intake: Take 4-6 capsules after the evening meal, but before 9 PM
• No breakfast: On the morning of the exam
• Report to x-ray department: In the morning

Patient Interview for Oral Cholecystography

• Number of pills: How many were taken and at what time?
• Reactions: Did the patient experience any reactions to the pills?
• Breakfast: Did the patient have breakfast?
• Gallbladder presence: Has the patient had their gallbladder removed?
• Pregnancy: For female patients of childbearing age, ask about pregnancy.

Imaging Routine for Oral Cholecystography

• Scout: PA projection (10x12 or 14x17)
  • Purpose: Determine presence and location of the gallbladder, identify choleliths, assess C.A. concentration, and confirm proper exposure factors
  • Some departments may require a full abdomen, centering the PA at the level of the iliac crest or slightly above

Positioning for Oral Cholecystography

• Prone:

  • Position: Align MSP with the long axis of the table, centering the right side of the abdomen
  • CR: Perpendicular to IR
  • CR level: L2 for average sthenic patients, ½ to 1” above the lowest margin of the rib cage
  • IR centered to CR
  • Instructions: Suspended respiration, focusing on the gallbladder and the cystic duct area
  • SS: Opacified region

• LAO (10x12 lengthwise):

  • Position: Semiprone, left side down
  • Rotation: 15-40° (less for hyperstenic, more for asthenic patients)
  • CR: Perpendicular
  • Instructions: Suspended respiration upon expiration
  • SS: Same as prone

• Right Lateral Decubitus (10x12 lengthwise):

  • Position: Patient lying on right side facing the IR, supported by radiolucent pads
  • CR: Horizontal
  • Instructions: Suspended respiration upon expiration
  • SS: Provides visualization of the gallbladder away from the vertebrae, stratifying stones

• PA Erect (10x12 lengthwise):

  • Position: Patient erect facing the VGCH
  • CR: Horizontal
  • Instructions: Suspended respiration upon expiration
  • SS: Entire opacified gallbladder and the cystic duct area

Operative (Immediate) Cholangiography

• Performed during surgery
• Purposes:
  • Identify any missed stones
  • Evaluate the patency of the biliary ducts
  • Determine the status of the papilla of Vater
  • Identify lesions (strictures, dilatations) in the ducts
• Procedure:
  • Contrast media is injected through a catheter inserted into the cystic duct

Post-Operative (T-Tube or Delayed) Cholangiography

• Performed after cholecystectomy (gallbladder removal)
• T-tube: A specific catheter inserted into the common bile duct, extending outside the body

Percutaneous Transhepatic Cholangiography (PTC)

• Direct puncture of the biliary ducts through the liver tissue
• Risks: Liver hemorrhage, pneumothorax (collapsed lung), bile leakage
• Procedure:
  • Needle insertion into the liver, guided by fluoroscopy
  • Contrast media is injected into the duct

Endoscopic Retrograde Cholangiopancreatography (ERCP)

• Therapeutic and diagnostic procedure
• Endoscope used: Duodenoscope
• Therapeutic: Relief of pathologic conditions, stone removal, lesion removal, stenosis repair
• Diagnostic: Injection of contrast media into the biliary ducts, guided by fluoroscopy

ERCP Precautions

• NPO: 1 hour or more before the procedure
• Patient history: Review for pancreatitis or pseudocyst of the pancreas
• Radiation protection: Ensure all individuals in the fluoroscopy room wear protective aprons

This quiz explores the various types of cholegraphy, focusing on the procedures, administration methods, and routes for contrast agents. It covers important distinctions in biliary tract imaging, including cholecystography and cholangiography. Test your knowledge on these radiologic exams and their applications.