Chapter 12 UGI + Biliary

Liver’s primary function

• Produces large amounts of bile (about 1 quart/day)

• Bile stored in gallbladder, used to break down and digest fats

Anatomy of the liver

• Two larger lobes (larger right + smaller left)

• Two smaller lobes only visible posteriorly (quadrate + caudate)

• Separated by falciform ligament

Difference between caudate and quadrate lobes

Caudate - Superior + posterior to quadrate
Quadrate - On inferior surface of right lobe between gallbladder and falciform ligament

Where is the IVC located in terms of the liver?

Contours over surface of the caudate lobe

Pathway of bile

Small lobules of liver → small ducts → left and right hepatic ducts → common hepatic duct → cystic duct to gallbladder (for storage) OR common bile duct → hepatopancreatic sphincter → descending duodenum

Anatomy of the gallbladder

About 4” in length

1. Neck

2. Body

3. Fundus

Functions of gallbladder

1. Store bile for future use (2-2.5 TBSP)

2. Concentrate bile using hydrolysis

3. Contract when cholecystokinin releases

Anatomy of common bile duct

• 3” in length, diameter of a straw

• Descends behind superior portion of duodenum and head of pancreas to enter descending duodenum

• 40% of people - CBD + pancreatic duct do NOT combine

• 60% of people - CBD + pancreatic duct combine (creating hepatopancreatic ampulla), common site of impaction of gallstones

Lateral view of gallbladder

• More anterior to midcoronal

• Duct system closer to midline

• Necessary to place GB closest to IR (prone)

• To drain GB, pt is placed supine

What does a LAO position demonstrate of the gallbladder?

• Cystic duct

• Neck, body, and fundus

What symptoms do gallbladder issues result in?

Nausea, vomiting, RUQ pain, heartburn, and feeling full

What’s the fancy word for gallstones

Choleliths

Choledocholithiasis

• Presence of stones

• Visualized using ERCP or cholangiography

Cholelithiasis

• Condition of abnormal calcifications, caused by an increase in bilirubin, calcium, or cholesterol

• Visualized using Cholescintigraphy

What are the two types of gallstones?

1. Cholesterol - 75%, highly radiolucent (unable to visualize)

2. Pigment

What are the only types of gallstones visible without contrast?

Crystalline calcium salt (about 20%)

What is milk calcium bile?

• Emulsion buildup of gallstones, visualized as sandlike calcifications

• Usually only helps to remove gallbladder (cholestectomy)

Cholecystitis

• Inflammation of gallbladder typically due to a blockage in the cystic duct

• Acute - due to blockages, infections, or ischemia

• Chronic - due to gallstones, pancreatitis, or a carcinoma

Neoplasms

• Rare growths, either malignant or benign

• Malignant - 85% adenocarcinoma, 15% squamous cell carcinoma, likely to spread to liver, pancreas, or GI tract

Biliary Stenosis

• Narrowing of a duct causing restriction of bile

• May prevent passing of small gallstones leading to obstruction or inflammation

What is the pathway of the alimentary canal?

Oral cavity → pharynx → esophagus → stomach → small intestine → large intestine → anus

What are the accessory organs of the GI system?

Pancreas, liver, gallbladder, and salivary glands

What are the 3 salivary glands?

1. Parotid - largest, near the ear

2. Submandibular - below mandible

3. Sublingual - below tongue

Opening between the esophagus + stomach

Esophagogastric Junction

What allows food/fluid through the esophagogastric junction?

Cardiac sphincter

What is the opening between the stomach and duodenum?

Pyloric Sphincter

Fundus of the stomach

• Top portion, looks like a balloon

• Lies lateral + superior to cardiac orifice

• Usually filled with air “gastric bubble”

• Tends to move with diaphragm

Body of stomach

• Main part

• Lower end has partially constricted area to separate body from pyloric area called angular notch

Pylorus of stomach

• Divided in two parts

• Antrum - slight dilation distal to angular notch

• Canal - ends at pyloric sphincter

The fundus + pyloric region of the stomach are slightly _____ to the stomach body

Posterior

Where does air + barium settle in the supine position?

• Heavy barium settles in fundus

• Gas settles in body and pylorus

Where does air + barium settle in the RAO prone position?

• Gas fills fundus of stomach

• Barium settles in anterior body/pylorus

Where does air + barium settle in the erect position?

• Gas rises to fill fundus

• Barium settles to fill pyloric region

• Air fluid levels

Anatomy of the duodenum

• 7-9” long, shortest and widest of the small bowels

• Close to head of pancreas, nestled in C-loop of duodenum

What are the four parts of the duodenum?

1. Superior - starts at pylorus, area of duodenal bulb, common site of ulcers (intraperitoneal)

2. Descending - largest segment, posses duodenal papilla where common bile + pancreatic duct open

3. Horizontal - curves to left to join 4th part

4. Ascending - ends to create duodenal flexure (junction of duodenum + jejunum, held in place by ligament of Treitz

GI system in hypersthenic

• Short lungs

• High diaphragm

• Large intestine extends entire abdominal cavity

• Gallbladder and stomach are high and transverse (T9-T12)

• Duodenal bulb is @ T11-T12 right to midline

GI system in hyposthenic/asthenic

• Long/narrow lungs

• Low diaphragm

• Large intestine pushed down low

• J-shaped stomach (T11-L5)

• Gallbladder + duodenal bulb (L3-L4)

GI system in sthenic

• J-shaped stomach (T11-L2)

• Duodenal bulb (L1-L2)

• Gallbladder less transverse midway from lat to midline

• Splenic flexure often quite high

What happens to abdominal organs when a patient goes from supine to erect

They drop about 1-2”

What parts of the GI system are visible without contrast?

Fundus of stomach and parts of the large bowel

What is negative/radiolucent contrast?

Swallowed air, CO2, and gas crystals (visualized as black)

What is positive/radiopaque contrast?

Barium and iodine

Characteristics of Barium Sulfate

• Extremely insolubility in water or aqueous liquids

• Must be chemically pure or it’s considered poisonous

• Expelled rectally

• Forms colloidal suspension when mixed with water (never fully dissolves)

Thin Barium

• 1 part to 1 part

• Consistency of a thin milkshake

• Used to study entire GI tract

Thick Barium

• 3-4 parts barium to 1 part water

• Consistency of cooked cereal

• Used to study esophagus

When should barium not be used?

If there’s any risk of it escaping into the peritoneal cavity (it can NOT be absorbed)

What is gastrografin

• Iodinated contrast, 37% organically bound iodine

• Body can absorb it

• Travels faster than barium

• Should not be used in severely dehydrated patients

What does double contrast mean?

• Using both radiolucent + radiopaque contrast

• Barium + room air/CO2 gas

• Gas crystals like calcium + magnesium can be used to create CO2 gas

What is an esophagography?

The use of radiopaque contrast (typically thin + thick barium) to visualize the pharynx and esophagus during swallowing

What are the clinical indications for an esophagography?

• Achalasia

• Anatomic anomalies

• Barrett Esophagus

• Dysphagia

• Esophageal varices

• Zenker diverticulum

What is an upper GI series?

Studying the function of lower esophagus, stomach, and duodenum typically using thin barium

Clinical Indications for an upper GI series

• Bezoar

• Diverticula

• Emesis

• Gastric carcinoma

• Gastritis

• Hiatal hernia

• Hypertrophic pyloric stenosis

• Ulcers

What should the kVp be for barium, double-contrast, and iodinated contrast studies?

Barium - 110-125

Double - 90-100

Iodine - 80-90

Why is a RAO better for an esophagography than an LAO?

Provides better visibility of esophagus

Zencker’s Diverticula

Found at the pharyngoesophageal junction at upper end of esophagus

Diverticula

Pouch of variable size occurring normally or created by herniation of a mucous membrane through a defect in its muscular coat

Traction Diverticulum

Involves all layers of the esophagus and results from adjacent scar tissue that pulls the esophagus toward the area of involvement, more frequently in the middle third of the esophagus

Esophageal Varices

Abnormally diluted veins in the distal esophagus often seen with acute liver disease, best demonstrated recumbent for more complete filling of the veins

Esophageal Reflux

Gastric contents return back through the gastric orifice and irritate the lining of the esophagus

Cleft Palate

Congenital anomaly where the roof of the mouth is open which allows food and fluid to pass into the nose

Esophageal Atresia

Congenital abnormality where esophagus fails to fully develop, causing choking/gagging/dyspnea/cyanosis

Hiatal Hernia

Protrusion of a structure into the thoracic cavity through the esophageal hiatus of diaphragm

Gastric/Peptic Ulcer

Erosion of the mucosal lining on stomach, could cause perforation if severe

Bezoar

Mass of undigested material that gets trapped in the stomach, could cause an obstruction

Polyp

Small mass growing from mucosal wall, could be malignant or benign

Achalasia

Neuromuscular disorder which results in failure of lower esophageal sphincter to relax causing dilation of the esophagus

Schatzke’s Ring

Type of hiatal hernia where esophagogastric junction has herniated through the diaphragmatic opening

Porcelain GB

Extensive calcification in the wall of the GB which forms an oval density that corresponds to the shape of GB. Blue discoloration and brittle consistency of wall.

Difference between cholecystogogue and cholecystopaque

Cholecystogogue - Agent that promotes contraction of GB (not contrast)

Cholecystopaque - Contrast media used for GB visualization