Biliary System and Liver

1 23 2014

Liver

Largest gland of body 2nd largest organWhat is the 1st ?

Skin

How much does it weigh?Approx. 3 lbs

Liver is only internal human organ capable of natural regeneration of lost tissue!

as little as 25% of a liver can regenerate into a whole liver

Not true regeneration!lobes removed do not regrow- function is restored, but not original form

(aka: compensatory growth)(in true regeneration, both original function

and form are restored)

2 major lobes:Right lobeLeft lobe

2 minor lobes: Caudate lobe- part of

right lobe -posterior Quadrate lobe - part

of right lobe -inferior

Falciform ligament divides liver into:

Functions of liver

Main function -formation of bileMaintain a proper level or glucose in bloodConvert glucose to glycogenProduce ureaMake certain amino acids Filter harmful substances from blood (alcohol)Store vitamins and mineralsProduce 80% of cholesterol

It has a dual blood supply!

Receives both oxygenated and deoxygenated blood (portal system)

1. Hepatic artery-

supplies liver with oxygenated blood from abdominal aorta to like any other part of body

2. Portal vein- carries deoxygenated blood from digestive organs to be modified and filtered by liver

blood then returns to heart (by hepatic veins) and is circulated to rest of body

What is unique about liver?

First Pass Effect Problem

Many drugs taken orally are substantially metabolized by portal system of liver before reaching general circulation

Known as “first pass effect”

Thus certain drugs can only be taken via certain other routes!suppositoryintravenouslyintramuscularlyaerosol inhalationsublingually

Nitroglycerin cannot be swallowed - liver would inactivate medication -must be taken under tongue or transdermally

Biliary System

Consists basically of :

1. gallbladder

2. bile ducts

(Excretory system of liver)

Biliary Combining Forms

chole – relationship with bile (aka: gall)

bladder – sac or bag serving as receptacle for a secretion

cyst – closed sac having distinct membrane and division with nearby tissue (May contain air, fluids, or semi-solid material)

docho – duct – tube or passage way for conducting a substance

angio - vesselgraph- representation of a set of objects

-iasis –presence of

-itis – inflammation of

2 Primary Functions of Biliary System

Aid in digestion- by controlling release of bile

(Bile - greenish-yellow fluid produced in liver (consisting of waste products, cholesterol, and bile salts)

(when excreted gives feces dark brown color)

Drain waste products from liver into duodenum

Gall bladder

Reservoir for bile from liver – 2oz. capacity (50 percent of bile is stored in gallbladder)

Concentrates bile How much bile does it

produce per day?1-3 pints

How does bile get into gallbladder?

Sphincter of Oddi closes up, and bile is re-routed up into GB for temporary storage when not needed

the release of bile from the gallbladder is stimulated by secretion of a hormone called cholecystokinin

When food containing fat enters digestive tract…

Transportation of bile sequence

Liver secretes bile- into right and left hepatic ducts which join to become common hepatic duct

which joins with cystic duct from gallbladder to become the:

common bile duct which joins with pancreatic duct to form a junction known as:

hepatopancreatic ampulla (or ampulla of vater

Spincter of Oddi (or spincter of hepatopancreatic ampulla)controls emptying of bile into duodenum

Gallstones

Hardened deposits of digestive fluid that can form in gallbladder

Range in size from grain of sand to

Can have one or hundreds!

1 in 10 people have gallstones (can’t see if not calcified!)

Two types of gallstones

80% are cholesterol stones:

usually yellow-green and made primarily of hardened cholesterol

20% are pigment stones: small, dark stones made of bilirubin

Risk Factors for Gallstones

Female Age 60 or older American Indian or Mexican heritageOverweight or obese Pregnant Eating a high-fat, high-cholesterol, or low fiber diet Family history of gallstones Diabetes Losing weight very quickly Taking cholesterol-lowering medications Taking medications containing estrogen (such as hormone therapy drugs)

Complications from Gallbladder Stones

Choledocholithiasis -presence of bile stones in ducts

Cholecystitis - bile sac

inflammation

Pancreatitis Increased risk of

gallbladder cancer (very rare)

Treatment for Gallstones

Surgical removal of gallbladder -Cholecystectomy

Use medicines to dissolve stones (isn't suitable for everyone -may take a very long time)

Shock-wave lithotripsy ( high-energy sound waves) to break gallstones into tiny fragments, then dissolved by medicines

If your gallbladder is removed…

No longer a holding space to store bile

Bile continuously runs out of liver, through the hepatic ducts, into common bile duct, and directly into small intestine

When a high-fat meal is eaten - not enough bile available to digest it properly

Can result in chronic diarrhea

Small intestine’s ability to absorb essential fatty acids, vitamins and minerals is compromised without help of gallbladder

Pancreas

Both an exocrine and endocrine gland!

Endocrine- (Isle of Langerhans) produces glucagon and insulin to regulate sugar metabolism

Exocrine- secretes digestive enzymes

Generally cannot be seen on radiographs

CholecystographyStudy of gallbladderOral contrast is used

CholangiographyStudy of biliary ductsIV contrast is used (may be injected directly into ducts)

Radiological exams of Gallbladder

(largely replaced by Ultrsound, CT, MRI, nuclear medicine)

Indications for Biliary Tract Exam

Cholelithiasis (gallstones) -bile calculi presence

Cholecystitis (inflammation of gallbladder)-bile sac inflammation

Check liver function

Biliary neoplasia (tumor or mass in biliary system)

Biliary stenosis (abnormal narrowing of ducts)

Demonstrate concentrating/emptying ability of gallbladder

Contraindications for performing Biliary Tract Exams

Allergy to contrastPyloric obstruction (blockage from

stomach to duodenum)Severe jaundiceMalabsorptionLiver dysfunction

Hepatocellular disease- liver typically inflamed and shows signs of injury

Patient Prep

Fat-free meal evening before

Oral contrast taken 2 to 3 hours after evening meal

NPO after midnight until examAvoid laxitaves less than 24 hours to avoid

prevent voiding of contrast medium with fecal material

Make sure patient can, will, and did follow instructions!

Early morning appointment

Position of Gallbladder RUQ In hypersthenic pt.

Superior and lateral In Asthenic

Inferior and nearer to spine

Shielding

What 3 things must you consider?

1. Are gonads within 2” of primary x-ray field after proper collimation?

2. Are clinical objectives compromised?

3. Does pt have reasonable reproductive potential?

Gallbladder Exam(Cholecystography)

Scout film will also demonstrate if contrast is visible in gallbladder

Dr. may do fluoroscopic examination

Post-fatty meal film may be obtained to demonstrate emptying ability of GB

PA Projection

Patient prone- or upright facing wallboard

Center 10x12 cassette at RUQ, level of the right elbow

70 - 80 kVp range

Exposure made at end of full? expiration

PA Oblique Projection

LAO position

Pt rotated 15 - 40 degrees depending on body habitus

CR at level of elbow, between spine and (R or L?) midaxillary line 10x12 cassette

Rt. Lateral Decubitus

Demonstrates stones lighter than bile visible only by stratification

CR:Directed horizontally

to level of gallbladder

Intravenous Cholangiography (IVC)

Very rarely performed anymore

Used when patients cannot tolerate oral contrast

Generally done in supine, and RPO positions

Films taken at timed intervals - up to about 40 minutes after injection

Percutaneous Transhepatic Cholangiography(performed preoperatively)

((Percutaneous: any medical procedure where access to inner organs or other tissue is done via needle-puncture of skin, rather than by scapel)

Long needle (Chiba) is placed into bile ducts

Contrast is injected under fluoroBiliary drainage or stone extraction may accompany this procedure

Cholangiography Intra-operative

Performed during a cholecystectomy

Examines patency of ducts during or after surgical removal of GB

T-Tube Cholangiography

Post-operative (after cholecystectomy) procedure performed through T-tube left in common hepatic and common bile ducts (for drainage)

To determine: patency (openness) of

biliary ducts after cholecystectomy

status of Spincter of oddi

presence of residual or

undetected stones

IntraoperativePercutaneous

3 Cholangiogram types compared

T-Tube

ERCP

Used to diagnose biliary and pancreatic pathologic conditions

when ducts are not dilated and ampulla is not obstructed

Fiberoptic endoscope passed through mouth into duodenum under fluoroscopyCommon bile duct is catheterizedContrast is injected

Endoscopic Retrograde Cholangiopancreatography