Biliary system

BILIARY SYSTEM consists of and contributes to ..

•Consists of gallbladder and ducts that drain the liver of bile

•Contributes to digestive process along with liver and pancreas

Biliary duct function

allow bile to flow to gallbladder (tansports bile)

Gallbladder functions

acts as reservoir for BILE (stores and concentrates bile)

GB location

mostly intraperitoneal and situated on the posterior surface of the liver

Cystic artery arises from and supplies

arises from the RT hepatic artery & supplies the GB and hepatic ducts

Function of the Biliary System

•Hepatocytes make bile

•Drain the liver of bile

•Store the bile until it is needed to aid digestion

Biliary System Anatomy

• Intimately associated with the liver and pancreas

• Consists of:

• Gallbladder

• Intra and Extra hepatic bile ducts

Biliary Tree Anatomy

•Common hepatic duct joins the cystic duct to form the common bile duct

•Common bile duct empties into the duodenum

Indication for Exam (WO)

•Pain

•Right upper quadrant (RUQ) pain

•Right shoulder pain / scapula (with inflammation)

•Positive Murphy’s sign

•Nausea

•Vomiting

•Intolerance to fatty foods and dairy products

•Jaundice or abnormal liver function tests (LFTs)

•Loss of appetite

Patient preparation

NPO 6-8 hrs

Transducer selection

Curved, linear phased, higher frequency when possible

Patient positioning

supine, LDEC, RDEC to use liver as a “backdrop”. Can appreciate small stones and shadows which sometimes are not appreciated due to bowel gas

Image optimization

DEPTH, SECTION WIDTH and FOCAL ZONE!!!!! harmonics, compression, intercostal, anterior artifact is often present due to reverb from abdominal wall and adipose. Do not clean up too much as you may miss sludge.

Examination protocol

probe at inferior rt liver at costal margin

Scan superior to inferior and side to side

look carefully in the neck for small stones

Examination limitations

•Bowel gas

•Artifact (reverberation)

•Pt unable to hold breath

•Pt ate

•NPO 6-8hrs

(suspected Cholecystitis ? – do it)

•Obesity

gallbladder wall should not be more than …

2-3mm in thickness (3mm is considered abnormal)

Normal measurements

k

Associated Tests

•Oral cholecystogram

•Nuclear medicine (HIDA scan)

•Computed axial tomography (CT scan)

•Cholangiography

•Endoscopic retrograde cholangiopancreatography (ERCP)

•Hepatobiliary scintigraphy

•Endoscopic ultrasonography (EUS)

Gallbladder Anatomy

•Variety of shapes

• Neck is superior, fundus is inferior

Where is bile made and how does it get to the hapetocytes ? (WO)

1. Bile is produced by liver (HEPATOCYTES) and carried to the gastrointestinal system by the biliary tract

2. Sphincter of Oddi, in the duodenum, regulates passage of bile into the duodenum, and at the same time prevents reflux of gastrointestinal fluids into the biliary system.

3. When closed, the sphincter of Oddi forces the gallbladder to fill with bile

4. When fats and amino acids are ingested, the duodenal mucosa releases cholecystokinin (CCK)

Where is bile more concentrated ?

Bile in the gallbladder is much more concentrated than hepatic bile

What is bile composed of ?

mostly water (82%) and bile acids (12%)

Remaining constituents include cholesterol, bilirubin (bile pigment), proteins, electrolytes, and mucus

What supplies the GB?

Cystic artery supplies GB

What supplies the gallbladder and liver ?

Proper/ Right hepatic artery supplies the gallbladder and liver

Where does the cystic artery originate ?

may originate directly from the common hepatic artery or, rarely, from the gastroduodenal artery

Venous drainage of the gallbladder is by way of the

hepatic portal system

What is the only O2 supply to biliary system?

CYSTIC ARTERY IS ONLY O2 SUPPLY TO BILIARY SYSTEM.

•GB wall layers

Serosal: outer most layer, connective tissue

Subserosa Muscularis: middle layer, muscular

Mucosa: innermost layer, epithelial cells with folds

Rokitansky-Aschoff sinuses

Rugae or pocket-like invaginations of the epithelium into the muscularis

GB Wall 3 or more mm…

•Rokitansky-Aschoff sinuses rugae

Adenomyomatosis

Wall thickness measurement

Wall should be measured on the anterior border when the wall is perpendicular to the transducer.

GB Location

• Intraperitoneal cavity

• Anterior*

• Superior & Anterior to RK

• Relationship to liver & gut

bile reservoir

• on posteroinferior surface of liver

• Divided into:

•Fundus

•Body

•Neck

•1. FUNDUS -

1. Is the bottom of the pouch (inferior)

2. Most distal and inferolateral portion of GB

3. Projects below the inferior margin of liver

4. Close to hepatic flexure of colon & duodenum

5. Lateral to duodenum & pancreatic head

5. Can be palpated if GB is inflamed or enlarged

•2. BODY -

1. Portion between neck & fundus

2. Is in contact with the visceral surface of liver

•3. NECK -

1. Narrowing area leading to the cystic duct

2. Is continuous with cystic duct

3. Orientated posteromedially towards the porta hepatis

Laboratory Values

•White Blood Count (WBC)

•Serum bilirubin

•Serum alkaline phosphatase (ALP)

•Liver Function Tests (LFTs)

•1) Aspartate aminotransferase (AST)

•2) Alanine aminotransferase (ALT)

•3) Prothrombin time (PT)

GB protocols

•AIUM & ACR GUIDELINES

Sonography of Gallbladder

•Anechoic lumen with thin smooth walls

•Sonolucent oblong ANTERIOR structure located anterior to RK, lateral to head of panc & duodenum.

•Fundus is slightly more anterior. This is appreciated on sagittal scans.

•Main lobar fissure can be used to identify the GB. It is located between the GB and RPV. GB is inferior to MLF.

•Hyperehoic wall <3mm

What is palpatation of GB used to evaluate for ?

Murphy’s Sign

Anterior Reverberation Artifact Versus Sludge

Scanning intercostal can eliminate this artifact, scan inferior to see fundus well.

use a higher frequency probe to inspect the fundus, also helping to eliminate the artifact.

The fundus is ….

ANTERIOR and INFERIOR

Gallbladder Fossa

Indentation located on the posteroinferior portion of the right lobe of the liver where the gallbladder is situated

Main Lobar Fissure

•Thin hyperechoic line between the portal vein and gallbladder

•Landmark for locating the gallbladder and gallbladder fossa

HARTMANN’S POUCH

out pouching, forms when the neck of GB folds on itself

PHRYGIAN CAP

forms when the fundus of the GB bends/folds on itself.

JUNCTIONAL FOLD

forms when the GB folds on itself in the region where the neck & the body meet

DUPLICATION DOUBLE GB

rare (1/ 4000), hard to diagnose on US.

Appears as two parallel cystic structures in the GB fossa

SEPTATED

septations seen within GB

other normal varients of the GB

Rare agenesis, hypoplasia (underdeveloped), opening directly into duodenum, left sided with situs inversus

Common Normal Variants

•Phrygian cap at fundus

•Junctional Fold

•Hartmann's pouch

1) junctional fold

2) phrygian cap

BILE DUCTS

•Transports bile: liver to GB & GB to duodenum

•Surrounded by a CT sheath, which gives hyperechoic appearance

RIGHT & LEFT BILE DUCTS

completely enclosed by the liver and considered INTRAHEPATIC

COMMON BILE DUCT, CYSTIC DUCT & PART OF COMMON HEPATIC DUCT

are not enclosed by the liver and considered EXTRAHEPATIC

Bile Ducts sonography

• avascular, anechoic lumens which vary in size

• Intrahepatic ducts are normally not seen.

• Bright/Hyperechoic walls

Intrahepatic Right and Left Ducts sonography

• Normally not seen

• <2mm or <40% of PV

• Adjacent to PV (linear structures)

Which structure is not routinely seen on US ?

Cystic duct is not routinely seen.

What structures are routinely seen on US ?

CHD & CBD are routinely seen

The common hepatic duct is the union of….

Rt and Lt (intra and extra) hepatic ducts

Cystic Duct

Joins the CHD

Extrahepatic

Bi-directional bile flow

spiral valves of heister

Common Bile Duct

Union of CHD & CD

Extrahepatic

Hepatoduodenal ligament

common bile duct

common bile duct

Portal triad

CBD forms Portal Triad along with portal vein & hepatic artery.

MICKEYS SIGN:

PV=face, HA=Lt ear, CBD=Rt ear

distal CBD

measuring CBD

follow any dilatation to the obstruction

distal CBD

Right and left INTRA hepatic ducts diameter

0.1 - 0.2 mm in diameter

Common bile duct measurement

5-15cm in length

0.1-0.7 cm in diameter

Intrahepatic ducts

•Formed from canaliculi, which drain into the right & left hepatic ducts

•2mm or less

•Should not be more than 40% of the diameter of the adjacent portal vein.

•not normally seen

Rt & Lt hepatic ducts

drain bile from rt & lt lobes and bring bile to GB through cystic duct

run parallel & anterior to Rt & Lt Portal Vein

The Common Hepatic Duct is the union of

Rt & Lt intrahepatic bile ducts

Common Hepatic Duct

• 2 mm in diameter

•Is slightly intra & extra hepatic

Common hepatic duct is formed by the union of …

rt and lt intrahepatic ducts

Common hepatic duct joins with the cystic duct to form….

extrahepatic common bile duct

common hepatic duct

CYSTIC DUCT

•3-4 cm long (average), EXTRAHEPATIC

•1-4 mm in diameter

•S shape

•Usually not seen on ultrasound

The cystic duct connects

the GB neck to CHD

Bile from the hepatocytes flows through ___ to get to the ___

Bile from the Hepatocytes flows through cystic duct to get to the GB

Spiral valves of heister

mucosal folds in the cystic duct

What forms the common bile duct ?

the union of the cystic duct and the common hepatic duct

SPIRAL VALVES OF HEISTER

• prevent the duct from over distending folding & kinking on itself….does not control flow of bile. Bile flows freely in both directions in cystic duct. Pressures in the biliary along with GB contraction control the flow of bile.

• These valves may cause shadowing and should not be confused with stones.

COMMON BILE DUCT

•CBD AP measurements ranging upper limits of normal 1-7mm.

•Union of cystic duct & common hepatic duct

•Located anterolateral to Main Portal Vein

•Range of 6 to 11.5 cm in length.

COMMON BILE DUCT Courses through ….

the Hepatoduodenal Ligament

AMPULLA OF VATER aka

hepatopancreatic ampulla.

AMPULLA OF VATER

point where the CBD and PANCREATIC DUCT unite and join the duodenum

SPHINCTER OF ODDI

muscle sheathe surrounding the end of the CBD and pancreatic ducts (ampulla of vater)

regulates the bile and pancreatic juices into the duodenum

CBD transverses…

the POSTERIOR aspect of the head of the pancreas and uncinate process

Cholecystectomy

removal of GB

•Post cholecystectomy the diameter of the CBD can exceed 10 mm / 1cm.

Loss of GB =

loss of contraction & relaxation. Sphincter of Oddi loses its tonus, remains open for several months after cholecystectomy & extra hepatic bile ducts may dilate and concentrate bile - substituting as a one of the function lost from the GB removal. If the common & hepatic ducts start to concentrate bile they are then susceptible to stone formation by precipitation of biliary solids.

CHOLEDOCHAL CYSTS

(3 TYPES) can be seen as anechoic masses connected to the CBD or CHD (porta hepatis - to doudenal insertion)

Congenital Cystic Dilatation

most common is a localized dilatation of the CBD. A “fusiform” dilatation.

Intraduodenal (choledochocele)

an entangled or herniated CBD enters the duodenum

Congenital diverticulum

outpouching of the wall of the CBD, may be seen as separate or loosely attached structure to the CBD

choledochal cysts

Cholelithiasis

gb stone

Choledocholithiasis

stone in the bile duct

Cholecystitis

inflamed gb