The Liver Flashcards
The liver is located in these 3 abdominal regions
- the right hypochondrium
- the greater part of the epigastrium
- the left hypochondrium as far as the mammillary line
Which is true? The contour and shape of the liver may vary or stays the same.
-may vary
The liver lies _____ to the diaphragm.
-inferior
These cover the greater part of the right lobe of the liver.
-ribs
The liver extends several centimeters below the xiphoid process in this region.
-epigastric
Fluid build up around the liver is called
-ascites
The texture of the liver is
-homogeneous with fine-low level echos
This area is inferior to the lungs and superior to the liver
-subphrenic recess
This area is inferior to the liver and superior to the right kidney
-subhepatic space
The echogenicity of the cortex around the kidney is
-hypoechoic
The echogenicity of the center of the kidney is
-hyperechoic
The echogenicity of the diaphragm is
-hyperechoic
The liver is housed and stays in place by
-ligaments
This line is where anterior to posterior measurements are taken
-mid-clavicle line
This fold in the parietal peritoneum extends from the umbilicus to the diaphragm and contains the ligamentum teres
-falciform ligament
Remnant of the obliterated left umbilical vein seen as a triangular echogenic foci dividing the medial and lateral segments of the left lobe of the liver in the transverse plane
-ligamentum teres
This area is not covered by peritoneum
-bare area
A fibroelastic, connective tissue layer that surrounds the liver
-Glisson Capsule
Transverse measurement of liver
20-22.5cm
AP measurement of liver
10-12.5cm
Length measurement of liver
15-17cm
Enlargement of the liver(anything over 17cm) is called
-hepatomegaly
Dual blood supply from these two vessels
-portal vein and hepatic artery
This blood supply to the liver is oxygen rich
-hepatic artery
This blood supply to the liver is nutrient rich
-portal vein
The porta hepatis consists of the
-portal vein(largest), common bile duct(L), and the hepatic artery(R)
Signs and symptoms of liver disease are:
-anorexia, fatigue, fever, jaundice, hepatomegaly, and Abn LFT
Normal common bile duct measurements
4-8mm
Which hepatic artery is larger than the other
-Right, since the right lobe is larger
Will a diseased liver effect the caudate lobe? Why or why not?
-No, it has its own separate blood supply.
Couinaud system breaks the liver into
-8 segments
Segment I
Caudate Lobe
Segment II
Superior lateral segment
Segment III
Inferior lateral segment
Segments IVa and IVb
Medial segments
Segment V
Inferior anterior segment
Segment VI
Inferior posterior segment
Segment VII
Superior posterior segment
Segment VIII
Superior anterior segment
These two things appear echogenic and hyperechoic because of the presence of collagen and fat within and around the structures.
-ligaments and fissures
Name the 5 ligaments or fissures of the liver:
-Glisson capsule, main lobar fissure, falciform ligament, ligamentum teres(round lig.), ligamentum venosum
Divides the right and left lobes of the liver; seen in the sagittal plane as an echogenic line between the gallbladder neck and the main portal vein
-Main lobar fissure
This ligament appears bright echogenic focus in the left lobe of the liver in the transverse image.
-Ligamentum teres
Remnant of the ductus venosus seen as an echogenic line separating the caudate lobe from the left lobe
-Ligamentum venosum
The portal venous supply for the liver is made up of
-Main portal vein, right portal vein, and left portal vein
These veins carry blood from the bowel to the liver
-Portal veins
These veins drain blood from the liver into the IVC
-Hepatic veins
This transports bile, which is manufactured in the liver, to the duodenum.
-Bile ducts
This term refers to when portal veins do not drain blood from the liver.
-Hepatic feugal
Do portal veins have more or less echogenic borders than the hepatic veins?
-more echogenic
The hepatic artery may be seen posterior to the portal vein on the oblique transverse view which is known as the
-portal triad
Hepatic metabolic functions of the liver:
- converts sugars(carbs) into glucose
- converts glucose into glycogen and stores it
- metabolizes fats
- converts dietary fats into hepatocytes to lipoproteins
- uses stored fats for energy
Other functions of the liver include:
- manufactures plasma proteins
- converts excess amino acids into fatty acids and urea
- removes nutrients from blood
- phagocytizes bacteria and worn-out RBCs
The liver’s role in digestion:
- secretes bile(digests fats)
- releases bilirubin when RBCs are broken down
Storage function of the liver:
-iron and certain vitamins(K)
Detoxification function of the liver:
-filters drugs, poisons, and waste products of metabolic process from the body
Hepatocellular disease
- Liver cells(hepatocytes) are the immediate problem
- Effects liver function
- Treated medically w/supportive measures and drugs
Obstructive disorders
- Bile excretion blocked
- Treated surgically
Bilirubin detoxification
- liver excretes bilirubin into the gut vie the biliary tree
- after 120 days in the circulatory system, RBCs are trapped and broken down by reticuloendothelial cells, primarily in the spleen.
- hemoglobin from RBCs converted to bilirubin w/i reticuloendothelial system then released into bloodstream
- bilirubin molecules attach to albumin in blood and are transported to liver
Metabolism of Bilirubin in Hepatocytes
- Uptake: bilirubin separated from albumin and taken to hepatocytes
- Conjugation: bilirubin molecule combined with 2 glucuronide molecules, forming bilirubin diglucuronide
- Excretion: Bili molecule actively transported into bile canaliculi, then released from hepatocytes and passes through bile ducts and delivered to the bowel
Biliary obstruction
- hepatocytes pick up bilirubin and conjugate it w/glucuronide, but cannot dispose it
- conjugated form regurgitated into bloodstream with elevation of direct-acting bilirubin fraction
- indirect-acting bilirubin may rise slightly w/obstruction, but direct bilirubin predominates
What form of bilirubin predominates in hepatocellular disease?
-direct or conjugated
What is the excretory product of the liver?
-bile
Bile is continuously formed by hepatocytes and collects in
-bile canaliculi (bile ducts)
Bile is made of
-water, bile salts, and bile pigments
other components: cholesterol, lecithin, and protein
Primary functions of bile:
- emulsify fats
- removes waste products excreted by liver
Blood flow toward the liver; normal flow of portal veins
-hepatopetal
Blood flow away from the liver; normal flow of hepatic veins
-hepatofugal
Patient preparation for liver evaluation
-NPO for 6 hours before scan to eliminate bowel gas and ensure fullness of gallbladder
Patient position for liver evaluation
-supine or right anterior oblique position; deep inspirations allow the liver to move inferior to the rib cage
Completer survey of liver includes
-transverse, coronal, subcostal oblique, and sagittal views
What lies within the homogeneous parenchyma?
-hepatic veins, portal veins, hepatic arteries, and hepatic duct
Are the hepatic veins thick or thin walled?
-thin walled(hypoechoic)
Are the portal veins dim or brightly reflective?
-brightly reflective(hyperechoic)
With color-flow Doppler imaging, how does the portal veins flow?
-hepatopetal(toward the liver)
With color-flow Doppler imaging, how does the hepaitc vein flow?
-hepatofeugal(away from the liver)
Before beginning a liver exam, the parameters should be adjusted:
- TGC
- overall gain
- transducer frequency and type
- depth and focus
Liver assessment criteria
- size in SAG plane
- texture
- attenuation of liver parenchyma
- presence of hepatic vascular structures, ligaments, and fissures
This separates the right lobe from the left lobe of the liver
-main lobar fissure
This passes through the gallbladder fossa to the IVC
-main lobar fissure
This divides the right lobe of the liver into anterior and posterior segments
-right intersegmental fissure
This divides the left lobe into medial and lateral segments
-left intersegmental fissure
Are fissure hyperechoic or hypoechoic?
-hyperechoic
This is found on the posterior aspect of the liver, with the IVC on its posterior border and the ligamentum venosum on the anterior border
-Caudate lobe
These course bewteen the lobes(interlobal) and between the segments(intersegmental) of the liver
-Hepatic veins
What major branches of veins run centrally within the segments?
-Portal veins
This vein runs in the left intersegmental fissure
-ascending portion of the left portal vein
The liver is _____ to _____ when compared with the renal cortex of the kidney, and ______ when compared to the spleen.
-hyperechoic, isochoic, hypoechoic
Diffuse disease is measured through a series of
- LFT or liver function tests
- hepatic enzyme levels elevated w/cell necrosis
The most common benign disease of the liver; usually in the posterior segment of right lobe
-Cavernous hemangioma
This is a reversible disorder of metabolism
-Fatty liver
This disorder implies increased lipid accumulation in hepatocytes and the result of major injury to the liver or a systemic disorder
-Fatty infiltration
These are not visible with fatty liver
-veins
Causes of Fatty Liver
- obesity
- excessive alcohol intake
- poorly controlled hyperlipidemia(high Choles.)
- diabetes
- excess corticosteroids
- pregnancy
- total parenteral hyperalimentation
- severe hepatitis
- glycogen storage disease
- cystic fibrosis
- pharmaceutical
What stage of fatty liver:
minimal diffuse increase in hepatic echogenicity with normal visualization of diaphragm and intrahepatic vascular borders
-Mild
What stage of fatty liver:
increased echogenicity with slightly impaired visualization of the diaphragm and intrahepatic vascular borders
-Moderate
What stage of fatty liver:
significant increase in echogenicity of the liver parenchyma, decreased penetration of the posterior segment of the right lobe, and decreased to poor visualization of the diaphragm and hepatic vessels
-Severe
This liver condition is most common cause of intrahepatic-portal hypertention
-Portal Venous Hypertension
This condition may develop when hepatopetal flow(towards liver) is impeded by a thrombus or tumor invasion
-Portal Hypertension
With portal hypertention, the liver is _____ in the early stage and ______ in the late stage.
-enlarged, small
Doppler techniques for Heptaic vascular flow
- Pulse repetition frequency(PRF)
- Sample volume size and placement
- Filters
- Pulse wave (PW) Doppler
- Color Doppler
- Measurements: peak, systolic velocity, resistance index
Diffuse abnormalities of the liver parenchyma
- biliary obstruction
- common duct stones and structures
- extrahepatic mass
- passive hepatic congestion
Simple Hepatic Cysts
- usually found incidental
- found more often in women than men
- round with acoustic enhancement, even echotexture, thin wall surrounds it
What is Situs Inversus?
-internal organs are mirrored from their normal positions(right on left, left on right)
What is Reidel’s Lobe?
-An anatomic variant in which the right lobe is enlarged and extends inferiorly as a tongue-like projection
This connects and reroute the portal vein with the R hepatic vein to relieve some pressure and give relief
-Portosystemic Shunt
a-fetoprotein; a tumor marker frequently elevated in cases of hepatocellular carcinoma and certain testicular cancers
AFP
alkaline phosphates; an enzyme found in liver tissue that can be elevated with biliary obstruction
ALP
alanine aminotransferase; a liver enzyme most specific to hepatocellular damage
ALT
aspartate aminotransferase; an enzyme found in all tissues, but in largest amounts in the liver, an increase can indicate hepatocellular damage
AST
Yellowish pigmentation of the skin and whites of the eyes caused by increased levels of bilirubin in the blood
-Jaundice
Known as the gate to the liver; a fissure when the portal vein and hepatic artery enter the liver and the common hepatic duct exits the liver
-Porta hepatis
