Radiological Interpretation Gastrointestinal System Reference notes: Radiology and Images for students – British medical Journal

Different Modalities of abdominal radiograph Plain abdominal radiograph (AXR) Contrast abdominal x ray films Ultrasound abdomen Computed Tomography of abdomen (CT) MRI Other interventional methods - ERCP

Today’s Session Plain abdominal radiograph (AXR) Contrast abdominal x ray films Computed Tomography of abdomen (CT)

Systematic approach of reading a plain AXR Technical details (preliminary information) Type or View of the x – ray film Look for abnormal Intra and Extra luminal gas Calcification Soft tissue (Solid organs) abnormalities Bony abnormalities

Technical details Name , Age and Sex of the patient Date on which the film was taken Purpose: To ensure that you interpret the results of the correct patient

Type of the AXR Three types: Supine films: Taken when patient is supine position Most commonly requested film Erect films: Only during some situations Visualization of air-fluid level Decubitus: Taken when patient is lying on his side (right or left)

Key to densities in AXRs Black – gas White – calcified structures Grey – soft tissues Darker grey – Fat Intense white – Metallic objects

Characteristics of Bowel loops Small bowel Size : < 3 cm Location: central Presence of Valvulae conniventes (Seen well when dilated) Large bowel Size : < 5 cm (Except caecum <9 cm) Location: Periphery Presence of Haustrations (Seen well when dilated)

Intra luminal Gas (Gas within the lumen of bowel) Normal Visibility depends on the amount of air Places to look for normal bowel gas are Stomach (Gastric air bubble) Intestine ( mc - caecum and rectum) Abnormal Should satisfy the criteria Due to Intestinal obstruction

Comparison of large and small bowel obstruction radiological features Bowel diameter: > 3 cm and < 5 cm Position: Central No. of loops: many loops Fluid level on erect film: many, short Bowel markings: Valvulae conniventes (all the way across) Large bowel > 5 cm (Except caecum > 9 cm) Peripheral Few Few, long Haustrations (partially across)

Small bowel Bowel diameter: > 3 cm and < 5 cm Position: Central No. of loops: many loops Fluid level on erect film: many, short Bowel markings: Valvulae conniventes (all the way across)

Volvulae Conniventes Volvulae Conniventes

Small bowel obstruction Adhesions (60%) Hernias (10%) Crohn’s disease Neoplasms (20%) Intussusception Volvulus Intestinal atresia Foreign body

Comparison of large and small bowel obstruction radiological features Large bowel > 5 cm (Except caecum > 9 cm) Peripheral Few Few, long Haustrations (partially across)

Common Causes of LBO Colon cancer Diverticulitis Volvulus Hernia Unlike SBO, adhesions very unlikely to produce LBO frequency

Multiple air fluid levels

Extra luminal gas (Gas outside the bowel) Called as Pneumoperitoneum Site to look for pneumoperitoneum under the right diaphragm (“air under diaphragm”) Most important and potentially devastating finding Indicates perforated viscus (most common) Emergency surgical intervention is necessary and life saving

Conditions causing extra luminal air Perforated abdominal viscus Abscesses (Subphrenic – most common) Biliary fistula Necrotizing enterocolitis

Calcifications Normal structures that calcify Abnormal structures that contain calcium

Normal structures that calcify Costal cartilage Mesenteric lymph nodes Pelvic vein clots (Phlebolith) Prostate gland

Abnormal structures that contain calcium Calcium indicates pathology: Pancreas Renal parenchyma Blood vessels and vascular aneurysms Gall bladder fibroids Calcium is pathology Biliary calculi Renal calculi Appendicolith Bladder calculi

Vascular calcification Renal calcifications-nephrocalcinosis Calcified uterine fibroid

Systematic approach to a contrast radiograph Special radiographs taken after ingestion of contrast material called barium To make the gut show up very well in some situations Part of the intestine to be examined decides the type of barium test

Barium sulfate Barium sulfate is a white crystalline powder with molecular weight of 233 and specific gravity of 4.5 Four ranges of barium sulfate concentrations are in common use Dilute 20-25%w/v barium for single contrast enemas Dense 85-100% barium for air contrast enemas Medium density 65-70%w/v for BMFT High density 225-250%w/v for UGI

Fluoroscopy machine

Types of the Barium tests Barium Swallow Barium Meal Barium follow through Small intestines enema Single contrast enema

Indications – most important Suspected obstruction Suspected calculus in any viscus Palpable abdominal mass (malignancy)

Subject preparation Subject takes clear fluids the day before the examination At 5.00 pm administer magnesium citrate At 10.00 pm ask the subject to take 4 tablets of dulcolax with one full glass of water

On the day of the procedure Nil per oral until the procedure is completed Administration of a dulcolux suppository

Barium swallow A fruit flavoured barium liquid is taken to the subject An AP or PA view of x – ray pictures are taken during swallowing The whole procedure takes 10 mins Purpose: Clinical conditions related to oesophagus and stomach can be visualized

Barium swallow indications Dysphagia Food or liquid getting stuck while swallowing Sensation of lump in the throat Pain during swallowing

Barium swallow

Normal impressions on the esophagus

Carcinoma esophagus Irregular narrowing mid esophagus ‘Apple core’ appearance Shouldering Soft tissue mass

Barium Meal Steps of the procedure are similar to barium swallow Purpose: Clinical conditions related to stomach and duodenum can be visualized better

Barium meal

Barium follow through Preliminary steps are similar to barium swallow Films are taken after 10 to 15 mins Purpose: Clinical conditions related to small intestines like ulcers, polyps and tumours can be visualized

Barium meal follow through

Barium enema indications Change in bowel habit Melena or blood in the stools Change in the shape of stools, pencil stools Anemia Previous h/o bowel cancer or polyps Family h/o bowel cancer or polyps Unexplained weight loss

Double contrast barium enema

CT abdomen Students expected to identify the normal abdominal viscera, vascular and bony structures

Indication To assess equivocal imaging findings Staging of hepatic neoplasm Diagnosis of abdominal masses Assessment of bliliary problems Diagnosis vascular lesions Assessment of suspected post traumatic complications

Computed tomography

stomach spleen

Left lobe Right lobe spleen

GB pancreas DC adr adr spleen Adr= adrenal gland DC= descending colon

adrenal

Case 1: This 67 year-old women presented to the surgical ward with a distended abdomen and vomiting. Present this x-ray Give a diagnosis and potential causes