Other Radiology of the GI Tract

What is fluoroscopy?

Uses fluorescent substances for x-ray taking

Allows for real-time visualization of images

When do we use fluoroscopy?

Used very commonly for various arterial/venous catheter placements, cardiac catheters

Can also be used for GI imaging (oral contrast)

What is endoscopy?

Uses a tube with a camera at the end to visualize internal structures

What are some indications for GI endoscopy?

- Reflux esophagitis (and complications)

- Esophageal varices

- Esophageal cancer

- Gastric ulcer

- Gastric cancer

- GI bleeds

- Duodenal ulcer

- Celiac disease

- Pancreatic/biliary disease

- Colon cancers

- Intra-abdominal malignancies

What is EGD endoscopy?

Affords excellent view of mucosal surfaces of the esopagus, stomach and proximal duodenum

What is capsule endoscopy?

Novel imaging modality that permits the inspection of the small bowel

Capsule camera is swallowed, as it travels through the GI tract it takes images

What is enteroscopy?

Allows the visualization of a greater extent of the small bowel than the EGD

What is endoscopic ultrasound?

High frequency ultrasound transducer is incorporated into the tip of the endoscope which provides high resolution images of the GI wall and adjacent structures

What is ERCP?

Endoscopic retrograde cholangiopancreatography

Upper GI endoscopy and x-rays to treat problems of the bile and pancreatic ducts

What is laparoscopy?

Surgical technique that allows direct visualization of major portions of the liver, gallbladder, spleen, stoma, large and small bowel, pelvic organs and peritoneum

What is flexible sigmoidoscopy?

Examines rectum, sigmoid, and a variable length of more proximal colon

Does not go as deep as colonoscopy

What is colonoscopy?

Allows examination of the entire colon and rectum and frequently the terminal ileum

What are barium studies?

Evaluates the GI tract from mouth to rectum using oral contrast

Minor exposure to ionizing radiation

What are the different types of barium studies and what do they image?

- Barium swallow/esophagram: pharynx/esophagus only

- Upper GI series: esophagus, stomach, duodenum

- UGI with SBFT: portion of small bowel visualized

- Small bowel series

- Barium enema: for visualization of the colon

What are some indications for barium studies?

- Tumors

- Inflammation

- Hiatal hernias

- Zenker's diverticulum

- Obstructive dysphagia

- IBD

- Clarification of findings at endoscopy or imaging studies

What is achalasia?

Esophageal motility disorder in which the GES fails to relax

Due to problems with the myenteric plexus --> proximal esophagus will dilate due to the constant inability of foods and liquids to pass

What are symptoms of achalasia?

- Dysphagia

- Multiple episodes of vomiting undigested food

- Chest pain

- Weight loss

What is the imaging of choice for achalasia?

Barium swallow

Esophageal manometry is a key test to establish the diagnosis

How will achalasia present on barium swallow studies?

- No normal peristaltic movement of the esophagus

- Acute tapering at the LES

- Narrowing at the gastro-esophageal junction ("bird's beak")

What is a Zenker's diverticula?

Protrusion of pharyngeal mucosa due to loss of elasticity of the UES resulting in restricted opening during swallowing

Usually asymptomatic

What is the imaging of choice for Zenker's diverticula?

Barium esophagogram

How does Zenker's diverticula present on barium esophagogram?

Outpouching of barium that projects beyond the borders of the wall when viewed in profile

What is a hiatal hernia?

Protrusion of the gastroesophageal junction or stomach through the diaphragm

Two types: sliding (99%) and paraesophageal (1%)

What can we see on radiographs in patients with hiatal hernias?

- Failure of the esophagus to narrow

- Gastric mucosal folds extending above the diaphragm

What are risk factors for development of esophageal cancer?

- Tobacco

- EtOH

- History of Barrett's esophagus

What are the two types of esophageal cancer?

- Squamous cell

- Adenocarcinoma

What is the imaging modality of choice for diagnosis of esophageal cancer?

EGD and biopsy

Will visualize the extent of the cancer and can take a biopsy to stage it

Even though we do NOT use barium studies to diagnose esophageal cancer, structural changes can be seen. How would esophageal cancer present on barium studies?

- Annular constriction lesions

- Polypoid mass

- Superficial infiltrating lesion

- Ulceration and irregularity of the bowel wall

What other imaging modalities can be used to stage esophageal cancer?

- CT scan of chest and abdomen

- Endoscopic ultrasound (can demonstrate level of local mediastinal extension and local lymph node involvement)

What is Barrett's esophagus?

Metaplasia of the squamous cells of the esophagus that occurs due to acid damaging the lining of the esophagus and causing chronic esophagitis

What are peptic ulcers? Where do they usually occur?

Erosion of the GI tract due to mucosal damage secondary to pepsin and gastric acid secretion

Usually occur in stomach (gastric) and proximal duodenum (anterior wall of the bulb)

Which is more common: duodenal or gastric ulcer?

Duodenal (5:1)

What are risk factors for peptic ulcers?

- H. pylori

- NSAIDs

What is the imaging modality of choice for peptic ulcers?

EGD

When do we obtain CT scans for patients with peptic ulcers?

In patients with suspected complications of PUD (perforation, penetration, or obstruction)

What are risk factors for gastric adenocarcinoma?

- Chronic atrophic gastritis

- H. pylori

- Tobacco

- Heavy EtOH use

Where do most gastric adenocarcinomas arise?

Body and antrum of the stomach

What is the imaging modality of choice for gastric adenocarcinomas?

EGD with biopsy

What can we see on barium studies in a patient with gastric adenocarcinoma?

- Mass that protrudes in the stomach (filling defect)

- Rigid wall

- Irregular ulceration in a mass

- Thickened irregular gastric folds

- Won't be able to detect small or superficial lesions and cannot reliably distinguish benign from malignant ulcerations

What is a HIDA scan?

Hepatoiminodiacetic acid scan

Uses radioactive substance for visualization of the hepatobiliary tree, can be used for acute cholecystitis

What is the preferred endoscopic procedure in the initial evaluation of IBD?

Colonoscopy with ileoscopy

What are some endoscopic features of Crohn's disease?

- Combination of deep mucosal ulceration and nodular submucosal thickening --> "cobblestone" appearance

- Skip lesions

What are endoscopic findings of ulcerative colitis?

Loss of typical vascular pattern, granularity, friability, and ulceration

What can be seen on histology of biopsy of patients with ulcerative colitis?

- Inflammation of mucosa

- Atrophy of crypts

- Inflammatory cells

- Neutrophils

What are colonic polyps?

Protrusions of colonic mucosa that are slow growing and increase with age

Malignancy potential increases with size

What is the imaging study of choice for colonic polyp diagnosis?

Colonoscopy

What is the most common cancer of the GI tract?

Colon adenocarcinoma

Which populations are at higher risk of developing colon adenocarcinoma?

African Americans > Caucasians > Hispanics

Male and female have equal risk

How long does it take for an early premalignant lesion of the colon to progress to malignant cancer?

10-20 years

What is the imaging study of choice for patients with suspected colon adenocarcinoma (symptomatic individuals)?

Colonoscopy

What other imaging modalities are used once colon adenocarcinoma is discovered?

- CT

- MRI

- Chest x-ray

- PET

- Tumor markers