Liver
What are 6 ways to differentiate between hepatic and portal veins
1. ORIGIN 2. Collagen Content 3. branching patterns 4. Caliber Changes 5. Segmental Locations 6. Doppler Characteristics
How much does a healthy liver weigh?
1200 to 1600 g or 3.5lbs
How long is the liver?
15-17 cm
How many lobes are there in a liver?
3; right left and caudate
How many hepatic veins are there?
3; right, middle, and left
What is the right intersegmental fissure
A line drawn from the porta hepatis to the right hepatic vein
How does the ligamentum teres appear sonographically?
A triangular echogenic spot on transverse scan in left lobe
What is acites?
Accumulation of fluid in the liver
What is the right lobe divided into
Anterior and posterior segments by a short right intersegmental fissure
What is papillary process
Anteromedial extension of the caudate lobe may appear separate from the liver
Where does the main portal vein originate?
At the union of the splenic vein and superior mesenteric vein (portal splenic confluence)
The liver is covered by the peritoneum except in these 3 places
Bare Area: lies to the right of IVC in direct contact with diaphragm Fossa for Gallbladder Fossa for IVC
What creates the parallel channel sign (shotgun sign)
Bile ducts and portal veins travelling parallel to each other
What are the primary functions of the liver
Bile production and excretion excretion of hormones and drugs metabolism of fats, proteins, and carbohydrates enzyme activation Storage of glycogen, vitamins, and minerals Blood detox and purification
What artery branches off of the celiac axis?
Common Hepatic Artery
what are kupffer cells function?
Defense against invading organisms
How does the liver look in comparison to the diaphragm
Diaphragm should be 1/3 to 1/2 times brighter than liver
What does the common hepatic artery divide into and what does it supply?
Divides into right and left branches which supply the right and left lobes
What does the right intersegmental fissure divide into?
Divides the left lobe into medial and lateral segments
What is Couinaud's anatomy?
Divides the liver into 8 parts; used in Europe
How does the ligamentum teres divide the left lobe
Divides the medial from the lateral segment of the left lobe
What does Right Intersegmental fissure divide into?
Divides the right lobe into anterior and posterior segments
What is the liver drained by and what does it drain into?
Drained by the three hepatic veins (Right, Middle, Left) Drain into IVC
What is the falciform ligament?
Extrahepatic part of the ligamentum teres
What connects liver to the anterior abdominal wall?
Falciform Ligament
What seperates the right lobe from left lobe at diaphragmatic surface?
Falciform Ligament
what divides left lobe anteriorly from caudate lobe posteriorly
Fissure for ligamentum venosum
What is the porta hepatis?
Fissure through which portal vein and hepatic artery enter the liver common bile duct exit the liver
What is parenchyma tissue?
Functional tissue of liver; should appear homogeneous
What organ lives within the main lobar fissure ?
Gallbladder
The hepatic artery gives rise to these 3 arteries
Gastroduodenal artery Supraduodenal artery Right Gastric artery
The liver is enclosed by a fibrous capsule called?
Glisson's Capsule
Explain the caliber changes (diameter) of hepatic veins and portal veins
Hepatic Veins increase in diameter as they get closer to IVC Portal Veins diameter does not change
Explain the origin of the hepatic vein and the portal vein
Hepatic Veins: Drain into the IVC Portal Veins: Originate at the union of the splenic vein and SMA
Explain the collagen content for the hepatic veins and portal veins
Hepatic veins have less collagen in their walls (not as bright) Portal Veins have more collagen in their walls (brighter)
Explain the branching pattern for hepatic veins and portal veins
Hepatic veins travel longitudinally through the liver Portal Veins travels transversely through the liver
Explain the doppler characteristics of the hepatic vein and portal vein
Hepatic- Pulsatile Portal- continuous
What is the normal sonographic appearance of the liver ?
Homogenous; moderately echogenic throughout (low level echoes)
How does the liver look in comparison to the spleen
Hypoechoic or isoechoic
Where do all three hepatic veins drain into?
IVC
The right margin extends as a projection btwn the
IVC and the portal vein
Where is the right hepatic vein located and which lobe does is divide into what segments?
In the right intersegmental fissure and then into the right lobe into anterior and posterior segments
Where does the porta hepatis lie
Inferior surface of the liver on portal triad
Technique to view liver
Inspiration Valsalva maneuver Big Stomach Technique
How will the liver look if ascites is present?
It will look brighter
what is the length and AP diameter of Liver
L- 15-17cm AP- 11-13cm
The left lobe is divided cranially to caudally
Left Hepatic Vein Left portal vein ligamentum teres
Where is the left hepatic vein located and what does it divide
Left intersegmental fissure and divides the left lobe into medial and lateral segments
What does the ligamentum venosum separate?
Left lobe anteriorly from the caudate lobe posteriorly
What vein divides the left lobe anteriorly from caudate lobe posteriorly
Left portal vein
What is often mistaken for pathology in the left lobe of liver
Ligamentum Teres
What is the extension of the left portal vein called
Ligamentum Teres
What is the remnant of the fetal umbilical vein
Ligamentum Teres
What is the remnant of the fetal ductus venosus
Ligamentum Venosum
What is the largest organ in the body?
Liver
Where is the right hepatic vein located and what does it divide?
Located within the main lobar fissure and divides the liver into right and left lobes
What are the three lobar fissure in the liver
Main Lobar Fissure Right Intersegmental Fissure Left Intersegmental Fissure
The left lobe is divided into
Medial and lateral segments
What vein divides the right and left lobes cranially
Middle Hepatic Vein
Which of the two hepatic veins join together prior to draining into IVC
Middle and left
Patient Prep for Liver Exam
NPO from midnight; can take water with medication if necessary 6 hour fast if afternoon appointment
The portal vein
Nutrient Rich (80%)
What do portal veins bring into the liver? From Where?
Nutrient Rich Blood from the intestines
The Hepatic Artery is
Oxygen Rich (20%)
What are 2 normal variants of the liver
Papillary Process Reidel's Lobe
What brings nutrient rich blood to the liver?
Portal vein
What supplies the liver
Portal vein (80%) Hepatic artery (20%)
What is the old term for the medial left lobes of the liver
Quadrate Lobe
What does the main lobar fissure divide?
Right & Left Lobes
What fissure divides the right lobe into anterior and posterior segments?
Right Intersegmental Fissure
The IVC creates what kind of margin
Right Lateral Margin
Where does the caudate lobe get its blood supply?
Right and Left Portal Radicals, Hepatic Arterial Branches
At the porta hepatis what does the main portal vein divide into?
Right and Left Portal Vein
The right lobe contains the
Right hepatic Vein Right portal Vein
Which is larger the right or left lobe?
Right lobe is 6 times larger than left
How does the main lobar fissure appear sonographically
Thin echogenic line running from the right portal vein to the gallbladder fossa on a Sagittal Scan
How does the right portal vein travel into the right lobe? What does it branch into?
Travels Transversely; branches into anterior and posterior segments
How does the left portal vein travel into the left lobe what does it branch into?
Travels vertically; Branches into medial and lateral branches
What transducer do you use for liver
Usually btwn 3-5MHz; curved linear array or vector array
What is Reidel's lobe?
an inferior tongue-like projection of the right lobe of the liver extends as far as the iliac crest This anomaly is more common in women
What is the falciform ligament?
extrahepatic part of the ligamentum teres only seen with ascites
Where does the main lobar fissure extend from and to on a transverse scan
from Gallbladder to IVC
What brings oxygenated blood to the liver?
hepatic artery
Explain the segmental locations of hepatic veins and portal veins
hepatic veins are located between the segments (intersegmental) Portal Veins are located within the segments (intrasegmental)
What fissure divides the right and left lobes caudally?
main lobar fissure; extends from right portal vein to gallbladder
How does the liver look in comparison to the renal cortex
minimally hyperechoic
What does the portal triad consist of?
portal vein, hepatic artery, bile duct
Where is the liver located?
right hypochondriac with portions in the left hypochondrium and epigastric regions
What drains the caudate lobe of the liver?
short venous channels that extend directly from the posterior aspect into the IVC
What does the left margin of the caudate form
the hepatic boundary of the superior recess of the lesser sac
How are hepatic veins best seen?
transversely
Where is the caudate lobe located?
underneath the left side of the liver
