GI Radiology

Imaging modalities in GI Plain X-rays (Supine, Erect, Decubitus) Barium studies (Ba Swallow, Meal, Follow through, Enteroclysis, Enema) Ultrasound Abdomen CT Scan/MRI Abdomen ERCP, Cholangiography. Angiography and Nuclear Medicine

Plain Abdominal X-rays Erect Chest Supine Abdomen Erect / Decubitus Abdomen ( 10 min ) Radiation Dose ( 1 Abd = 75 CXR) Contraindicated – pregnancy

Indications. “Acute Abdomen” Abdominal Pain. ?Obstruction. Not Indicated for: Trauma. Solid organ assessment.

Basic Principles Five radiographic densities: Gas/Air Fat. Soft Tissue/Water Bone/Calcium Metals Interface/line only visible when two of these densities interface with each other.

Approach to a AXR Technical Assessment. Projection. Bowel/Gas Shadows. Normal/Abnormal Calcifications. Solid Organs. Look at lung bases and at the skeleton.

Normal Vs Abnormal Gas shadows Stomach. Colon. Small Bowel. Within the Lumen: Dilated bowel ?Obstruction Outside the Lumen: Free ?perforation In a cavity ?abscess

Contrast Medium for GI Water Soluble Ionic (gastrografin) Can lead to pulmonary edema if aspirated. Non- Ionic ( Low Osmolar) Relatively safer if aspirated. Gadolinium (MRI) Barium ( Non-water soluble) Can cause sever peritonitis and fibrosis in perforation or leakage.

Contrast Swallow Indications: Contraindications: Dysphagia Pain Reflux Anemia Tracheo-esophageal fistula Perforation Contraindications: Aspiration

Barium Meal Indications: Contraindications Pateint preparation: Dyspepsia Upper abdominal mass Weight Loss Gastrointestinal Hemorrhage. Partial Obstruction Assessment for perforation Contraindications Complete large bowel obstruction Pateint preparation: NPO ---6 hrs No smoking– increases GI motility

Small Bowel Follow through/ Small bowel enema (Enteroclysis) Indications: Pain Diarrhoea Anemia/GI bleed Partial Obstruction Malabsorption Abdominal mass Contraindications Complete obstruction Patient Preparation: Low residue diet Bowel Prep (Dulcolax -2-4 Tab)

Small Bowel follow through VS Small bowel enema

Barium Enema Indications: Change in bowel habits Pain Mass Melaena / Anemia Single contrast – Obstruction & Intussusception. Contraindications: Rectal biopsy—5 days Toxic megacolon Pseudomembranous colitis Preparation: (Two days) Low residue diet Bowel prep (Dulcolax – 4 Tab)

Ultrasound Abdomen Advantage Cost effective Adequate visceral visualization Best for GB No radiation Indications: Acute Abdomen, Obstructive jaundice, abdominal masses, collections, Free fluid, follow up- tumors. Disadvantage Operator dependent Poor in Obesity Bowel gasses Bones / Calcifications

CT Scan Abdomen Advantages Accurate & quick Bowel/ gasses/ bones Reformation and angio Indications: Acute abdomen, Abdominal mass, tumor staging/follow up, Appendicitis/abscesses, Post op complications Disadvantages: Radiation (250 CXR) Renal failure Contrast reaction

Multiple polyps

Apple core cancer on axial , volume randered (3D transparent image) and CT C images.

MRI Abdomen Advantages Disadvantages Multiplaner Renal failure MRCP Liver specific contrasts Disadvantages Bowel motion/ contrast Calcifications Metallic implant Relatively long procedure time Claustrophobia

Cholangiography Endoscopic Retrograde Cholangiopancreatography (ERCP) MR Cholangiopancreatography (MRCP) T-tube Cholangiography. Percutaneous Transhepatic Cholangiography (PTC).