Biliary Tree Flashcards
Biliary tree begins where?
Liver Lobules Bile Canaliculi
What is the biliary tree?
Intercommunicating network located between hepatocytes
The Rt and Lt Hepatic ducts are formed by the union of what?
Lobular ducts
Intrahepatic ducts should measure no longer than what? And exhibit what?
2mm in diameter and exhibit a branching pattern that parallels the portal veins
The sonographic appearance of dilated intrahepatic duct is often referred to as what?
Too many tubes
At the Porta hepatis the RT and LT duct join to form what?
Common hepatic duct
Where is the Common hepatic duct located anatomically in relation to the PV and the right hepatic artery?
- Anterior to PV
- Anterior and lateral to right hepatic artery
How is the common bile duct formed?
When the Common hepatic duct joins the cystic duct
CBD length is determined by what?
Insertion point
The CBD travels how in relation to the MPV?
Anterior and lateral
What is the normal diameter of the CBD?
4mm
What would change or vary the CBD diameter?
- Age
- Surgery
What would be the diameter of a post cholecystectomy patient?
Up to 10mm
What ligament does the CBD travel through?
Hepatoduodenal ligament
Where is the HA located in relation to the MPV?
Anterior and left micky mouse
How is the CBD located in relation to the MPV?
Anterior and right micky mouse
CBD is divided into how many parts?
4 parts relating to its position to the duodenum
Label the structures
- GB
- BD
- MPV
- IVC
**the arrow points towards the HA
Label the structures
- GB
- BD
- HA
- MPV
- IVC
- AO
The 4th part of the CBD is called what?
Intraduodenal
The 4th part of the CBD enters what part of the Duodenum and inserts into what?
Enters the 2nd part and inserts into the ampulla of vater
The 4th part of the CBD has the sphincter of oddi, what does it do?
Regulates bile flow
What is the narrowest part of the extrahepatic biliary tract?
4th part of the CBD
What does the CHD join above the duodenum?
The cystic duct 1-2 cm above the duodenum
The cystic duct arises from what?
The superior aspect of the neck of the GB
What is the shape of the cystic duct?
S shaped
What is the dimensions of the cystic ducts?
3mm diameter/ 4 cm in length
What valves does the Cystic duct contain?
The valves of heister
What are the valves of heister?
Mucosal folds that prevents the duct from over distending or collapsing
Where is the gallbladder located?
Posterior inferior surface of right liver in the GB fossa
In relation to the MLF where is the GB located?
Posterior and caudal
The position of the GB body and fundus varies with what?
Patient position
Which cavity is the gallbladder located?
Intraperitoneal
What are some landmarks for the GB? 4
- MLF
- RPV
- Duodenum
- Rt kidney
What is the shape of the gallbladder?
Pear or tear drop shape
What is the dimensions of the gallbladder? (Length and Diameter)
Length: 8-9 cm
Diameter: 3-5 cm
What is the gallbladder sections? 3
- Fundus
- Body
- Neck
what is the widest part of the gallbladder?
Fundas
Which section of the GB is the most dependent and fixed?
The neck
The GB wall should measure how much in a fasting state?
less than 3mm in a fasting state
What are the 4 layers of the GB wall?
- Mucosal layer
- Muscular layer
- Subserous Layer
- Serosa
What is the mucosal layer of the GB wall?
Inner epithelial Lining, concentrates bile
What is the muscular layer of the GB wall?
Muscle
What is the Subserous layer?
Connective tissue
What is the Serosa layer of the GB wall?
Outer layer in contact with the peritoneum
What are the Rokitansky- Aschoff (RA) sinuses?
Multiple folds along the inner border of the GB
Is the Rokitansky- Aschoff (RA) sinuses normally seen?
Not normally seen on U/S unless there is pathology
What is the function of the Bile ducts?
Drain the liver of bile and carry it to the GI system
What does the GB do? 2
- Reservior for bile (where bile is stored until required for digestion
- Concentrates bile by secreting mucous and absorbing water
How much bile does the GB hold?
~ 40-70 ml
Bile secretion is controlled by what?
Hormones
When would the duodenum release Cholecystokinin (CCK)?
With the ingestion of fats and amino acids
Cholecystokinin (CCK) stimulates the GB and the sphincter of Oddi to do what?
The GB to contract and the sphincter of Oddi to relax
GB contraction occurs when?
Within 30 minutes following a meal
What happens when the GB has been removed? 3
- Initially the sphincter of Oddi loses its tone
- Bile flows in the duodenum during fasting and non fasting states
- Some bile also remains in the ducts
After ~ 6 months after the GB has been removed, what happens to the sphincter?
It regains tone
After the GB has been removed the CBD may appear how?
Dilated (up to 10mm)
What is the bile?
Yellow- green liquid produced by hepatocytes
What does bile do?
Emulsifies fats and helps absorb fatty acids
How much bile salts are produced by the liver in a day?
1 gram/day
What is a precursor of bile salts?
Cholesterol
How do we get cholesterol in the body? 2
- Supplied by diet
- Synthesized by the liver
What is bilirubin?
Bile pigment which is the end product of hemoglobin decomposition
Where is bilirubin conjugated?
Liver
What is jaundice?
Yellowish tint seen in the body tissue due to large quantities of bilirubin
What is the arterial supply to the GB?
Cystic artery
What is the venous drainage of the GB?
Cystic vein (which drains into the portal venous system)
What are some variants of GB? 4
- Junctional fold
- Hartman’s pouch
- Phrygian pouch
- Septations
What is this variant of the GB?
Junctional Fold
What is this variant of the GB?
Hartman’s Pouch
What is this GB variant?
Phrygian cap
What is this GB variation?
Septation
What is this GB variation?
Septation
Label the structures
- RPV
- MLF
- GB
What is the sonographic appearance of the GB?
- Anechoic/ nearly anechoic structure
- Well defined, thin, echogenic walls
What is the sagittal shape of the GB?
Pear Shaped
What is the Transverse appearance of the GB?
Anechoic circle
What is the Patient prep for GB exams?
NPO for 6-8 hours
What probe do we use for GB exams?
2-6 MHz probe
What positions should the patient be in for GB exams?
- Supine
- LLD
Erect and prone positions can be used to rule out what?
Stones lodge in the neck and cystic duct
What do we Look for in GB exams? 5
- Size
- Shape
- Content
- Wall thickness
- Area surrounding GB
What are some techniques used to scan GB?
- Use harmonics to optimize
- Windows are important to minimize reverberation artifacts
How should we position Patients for Bile ducts?
LPO or decubitus
What do we measure in bile ducts?
- Porta hepatis area
- The duct inner wall to inner wall
** do not measure at the point where the duct crosses the HA**
Label the structure
- CBD
- PV
- HA
Label the structures
- CBD
- CHD
- HA
- PV
What are some lab test/ Other imaging we use for GB?
- Bilirubin (indirect/ direct)
- ALP
- Leukocytes (WBC) infection
- HIDA - Nuclear medicine
- ERCP - Fluoroscopy