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156 Cards in this Set
- Front
- Back
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From where do you measure the liver length?
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The midclavicular line.
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Why is the accuracy of liver measurements generally inconsistent?
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Because of the limited field of view.
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When do you use A-P method of measuring for the liver?
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When the patient is asthenic, or heavy. It helps avoid under or over estimation.
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Explain normal liver echogenicity.
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Homogeneous, isoechoic to slightly hyperechoic to the renal cortex, hypoechoic to the spleen.
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When the cystic duct and hepatic duct combine what do they form?
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The common bile duct.
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What does the portal triad consist of?
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Hepatic artery, hepatic duct, and portal vein.
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What is a WES sign?
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The shadow caused by a stone in the gallbladder. Sometimes this is the only way to identify gallbladder calcifications.
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Why is it important that the patient NPO for 6 hrs when scanning liver and gallbladder?
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Because gas from the duodenum is difficult to differentiate from a WES sign.
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What does the liver receive its blood supply via?
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The portal vein and hepatic artery.
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How oxygenated is the blood coming from the portal vein?
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80%
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Where does the portal vein come from?
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the intestines and spleen
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How much of the oxygen requirements for the hepatocytes is fulfilled by the blood from the portal vein?
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1/2 due to the large volume of flow
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compare and contrast the hepatic artery and portal vein
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The hepatic artery is a much smaller vessel than the portal system and it runs parallel to the portal system
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State the reason for extremely low incidence of hepatic infarction.
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Its dual blood supply.
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Name the place where blood flow enters the liver
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the portahepatis.
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What does hepatopedal mean
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normal flow direction of the hepatic artery and portal vein.
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In color mode what does a hepatopedal portahepatis look like?
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because the flow direction of both vessels is towards the transducer, they appear red.
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Which color should always be at the top of the scale when establishing flow direction at the portahepatis?
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Red (invert off)
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What are the terminal branches of the portal vein and partnering hepatic arterioles and bile ducts known as?
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the acinus
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explain the travel of blood through the liver parenchyma
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first it goes through the sinusoids and then enters the hepatic venules which then unite and form sequentially larger veins making the main hepatic veins that drain into the IVC
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what structures are normally hepatofugal
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the hepatic veins
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Explain what hepatofugal means and what it would like like in color mode
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blood flow away from the liver, blue
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55% of the population's (normal) common hepatic arises from where?
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the celiac trunk
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11% of the population has a vascular variation of.
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the common hepatic being replaced by the right hepatic arising from SMA
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10% of the population has a vascular variation of
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the common hepatic being replaced by the left hepatic arising from the left gastric artery
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2.5% of the population has a vascular variation of
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the common hepatic arising from the SMA
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Name three congenital variations of the Portal vein
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atresia, strictures, and obstructing valve
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Name two different portal vein variations
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an absence of the right portal vein (usually with have branching of the left and main portal veins to make up for it) and absence of the horizontal segment of the left portal vein.
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Name the most common (1/3 of the population) hepatic vein variation
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the accessory vein draining the (VIII) superoanterior segment of the right lobe drains into the right hepatic vein instead of the middle hepatic.
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Name the four things we asses about liver parenchyma
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size, contour, homogenicity, and configuration
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Are liver volumes accurate by ultrasound?
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no
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What is a hepatocyte?
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a parenchymal liver cell that performs functions of the liver
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What do LFTs measure?
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liver function tests check for diffuse hepatocellular disease
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name the subcategories of diffuse parenchymal disease
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fatty infiltration, acute and chronic hepatitis, early alcoholic liver disease, acute and chronic cirrhosis.
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What is the livers role in metabolism?
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it converts glucose to glycogen and stores it; manufactures plasma proteins; removes nutrients, broken down bacteria and worn out RBCs from the blood
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what is the livers role in digestion?
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produces bile, which is stored in the gallbladder, and is used to break down fats and bilirubin.
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What is bilirubin and what does a lack of it cause
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its a pigment that's released when RBCs are broken down, it causes jaundice
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What compounds does the liver store
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Iron, vitamins A, D, and K
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Whats the livers role in detoxifying the body?
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it detoxifies waste products of the metabolism and filters foreign chemicals out of the blood
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what is hepatocellular disease?
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when liver cells are the immediate cause of the problem
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what is obstructive disease?
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when bile excretion has been blocked
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Why is it important to know the difference between obstructive and hepatocellular diseases?
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because the treatments for each are very different
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what is an enzyme?
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a protein catalyst that is used throughout the body in the metabolic process
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What does elevated enzymes in the blood mean?
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hepatocellular disease is causing liver enzymes to leak into the blood stream
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Name three types of enzymes
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aspartase aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase
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Relate the different enzymes when there is disease present
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Though all these enzymes will increase in the bloodstream for both obstructive and hepatocellular diseases the pattern of elevation differs for both
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What will the enzyme serum levels be like for biliary obstruction
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AST and ALT with be mildly elevated, but less than 300 units. Alkaline phosphatase, which is extremely sensitive in obstruction, with show a marked elevation
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Sometimes alkaline phosphatase elevates before or rises disproportionally to serum bilirubin, what does this mean?
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It suggests biliary obstruction
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What does an elevation of 1000 units in both AST and ALT mean?
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Severe hepatocellular destruction such as acute viral or toxic hepatitis.
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What could enzyme fluctuation suggest?
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Cellular or obstructive disease, one may be masking the other, and obstruction can lead to cellular disease
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When could AST and ALT be elevated for a reason other than liver disease?
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heart or skeletal muscle damage
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when could alkaline phosphatase be elevated besides liver damage?
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pregnancy or bone disease
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Name the seven different types of liver function tests
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AST (SGOT), ALT (SGPT), LDH, Alkaline phophatse, Bilirubin (total, direct and indirect), Prothrombin Time, Albumin and Globulins
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Is agenesis of the liver compatible with life?
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NO!
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When is there usually compensatory hypertrophy in the liver?
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When there is agenesis of one lobe, the other hypertrophies to accommodate.
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Are LFTs normal when there is compensatory hypertrophy?
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yes
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What is situs inversus totalis?
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when the liver is found in the left hypocondrium as apposed to the right.
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What is congenital diaphragmatic hernia or omphalocele?
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when portions of the liver may herniate into the thorax or outside of the abdominal cavity
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What is fatty infiltration?
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When there is increased lipid accumulation in the hepatocytes.
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Why does fatty infiltration occur?
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Injury to the liver or systemic disorders leading to impaired or excessive metabolism of fat.
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Is fatty infiltration benign or malignant, is it reversible?
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Benign, and reversible
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List the symptoms of fatty infiltration
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usually asymptomatic, however there may be jaundice, nausea, and vomiting.
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List the six common causes of fatty infiltration.
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Alcoholic liver disease, diabetes mellitus, obesity, sever hepatitis, pregnancy, and steroids.
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What are the LFTs like for a person with fatty infiltration?
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mildly elevated
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What is steatosis
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another name for fatty infiltration
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What are the categories of steatosis?
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mild or grade 1, moderate or grade 2, and severe or grade 3
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What is focal sparring?
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when there is an area that is more hypoechoic than normal due to fatty infiltration in the rest of the liver. Found in cuadate lobe, gallbladder fossa, and liver margins.
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What is focal fatty infiltration?
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When there is an are of the liver that is hyperechoic due to fatty infiltration in that area.
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Explain the sonographic findings for mild steatosis
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minimal diffuse increase in parenchymal echogenicity in comparison to renal cortex. The diaphragm and intrahepatic vessels are defined.
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Explain the sonographic findings for moderate steatosis
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moderate diffuse increase in echogenicity of the liver parenchyma, visualization of the intrahepatic vessels may become impaired.
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Explain the sonographic findings for severe steatosis
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marked increase in echogenicty, poor penetration due to increased attenuation, and visualization of the diaphragm and intrahepatic vessels is difficult
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What do focal fatty sparring and infiltration have in common?
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they both mimic neoplastic involvement and appear in the area around the portahepatis or periportal region (segment 4)
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What is the lack of mass effect?
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hepatic vessels as a general rule are not displaced with discrete fatty liver disease
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Explain the sonographic findings of focal fat
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round, nodular, or interdigitated with normal tissue
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What is the prognosis for someone with steatosis.
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good, due to the rapid changes in fatty infiltration with time it may resolve in as early as 6 days.
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List the congenital abnormalities found in the liver
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liver cysts, peribiliary cysts, and adult polycystic disease
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Define a liver cyst
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a fluid filled space having an epitherlial lining.
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Are abscesses, parasitic cysts, and post traumatic cysts true cysts?
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NO
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What does frequent presence of columnar epithelium within hepatic cysts suggest?
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they have a ductal origin, the exact cause is not known
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What is the sonographic appearance of a benign hepatic cyst
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anechoic, with well defined thin walls and posterior acoustic enhancement
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What are the symptoms of benign hepatic cysts
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asymptomatic or pain and fever secondary to cyst hemorrhage or infection
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If a benign hepatic cyst has an infection or is hemorrhaged then what is the sonographic appearance
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internal echoes, septations, thickened walls, or solid.
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If complex appearing cyst is seen what is the the next step
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a CT because biliary cystadenomas or cystic metastases is a differential diagnosis.
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What is a Ridel's lobe?
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a tongue like extension off the inferior RLL nearby the kidney that does not change after probe and patient position changes.
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What are peribiliary cysts?
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obstructed periductal glands
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What are the symptoms of peribiliary cysts
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they are generally asymptomatic, but may rarely cause biliary obstruction.
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What are the sonographic findings associated with peribiliary cysts?
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small cyst usually 0.2-2.5 cm. usually appears as small discrete clustered cysts with tubular appearing structures within thin septae that parallel the bile ducts and portal veins.
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What is normal portal venous pressure
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5-10mmHg or 14cm H2O
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Portal hypertension is defined by a wedged hepatic vein pressure of greater than ______ above the IVC pressure
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5mmHg
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Portal hypertension is defined by a Splenic vein pressure of greater than
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15mmHg
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Portal hypertension is defined by a surgically measured portal vein pressure of greater than
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30cm H2O
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What are the two categories of portal hypertension
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Presinusoidal and Intrahepatic
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In presinusoidal portal hypertension the hepatic vein pressure is....
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normal
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If the hepatic wedge pressure is abnormally elevated it is considered
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intrahepatic portal hypertension
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Presinusoidal Portal Hypertension can be subdivided into
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intrahepatic and extrahepatic
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What is a cause of extrahepatic presinusoidal hypertension
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thrombosis of the portal or splenic veins
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What are the four causes of intrahepatic presinusoidal hypertension
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Schistosomiasis, primary biliary cirrhosis, congenital hepatic fibrosis, and toxic substances like methotrexate and polyvinyl chloride
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The diseases that cause intrahepatic presinusoidal hypertension affect the
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portal zone of the liver
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with presinusoidal hypertension the pressure is elevated ___ it gets to the sinusoids
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before
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with intrahepatic hypertension the pressure rises at the ____ _____
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hepatic veins
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What are the symptoms of extrahepatic presinusoidal portal hypertension
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-gastrointestinal bleeding
-ascites -encephalopathy -reduced levels of platelets or decreased WBC count |
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What are the symptoms of gastrointestinal bleeding
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black, tarry stools or blood in the stools,
vomiting of blood due to the spontaneous rupture and hemorrhage from varices |
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what is ascites?
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accumulation of fluid in the abdomen
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what is encephalopathy
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confusion and forgetfulness caused by poor liver function and the diversion of blood flow away from the liver
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With extrahepatic presinusoidal portal hypertension thrombosis of the portal venous system is often secondary to
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umbilical vein catherization
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Adult portal vein thrombosis could be caused by
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(Virchow's Triad) Trauma, sepsis, HCC, pancreatic carcinoma, pancreatitis, portacaval shunt, splenectomy, and hypercoagulable states
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What is the most common cause of intrahepatic portal hypertension
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cirrhosis
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What percent of the cases of portal hypertension in the west is caused by cirrhosis
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90%
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In cirrhosis, most of the normal liver architecture is replaced by ___ ____ created...
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distorted architecture, increased vascular resistance in portal venous blood flow and obstruction to hepatic venous outflow
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Other than cirrhosis, what causes intrahepatic portal hypertension through distorted architecture
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diffuse metastatic liver disease
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what causes intrahepatic portal hypertension
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thrombotic diseases of the IVC and hepatic veins, constrictive pericarditis
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What does constrictive pericarditis (or any severe right sided heart failure) lead to
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centrilobular fibrosis, hepatic regeneration, cirrhosis, and portal hypertension
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What is constrictive pericarditis
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when the pericardium is inflamed reducing elasticity
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What are the sonographic findings for portal hypertension
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splenomegaly
ascites portosystemic venous collaterals |
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when do portosystemic venous collaterals form
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when the resistance to blood flow in the portal vessels exceed the resistance to flow in the smaller communicating channels between the portal and systemic circulations
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Initially the portal vein diameter may increase with hypertension, but as collaterals develop
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the caliber will decrease
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Where are the five major site of collertal development (visualized by ultrasound)
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Gastroesophageal junction, paraumbilical vein, splenorenal and gastrorenal, intestinal, and hemorrhoidal
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Where is the gastroesophageal junction
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between the coronary and short gastric veins and the systemic veins
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If varices at the gastroesophageal junction rupture it may cause
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fatal hemorrhaging
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Dilation of the coronary vein >___ (or >___) is associated with severe portal hypertension
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7mm, 10mmHg
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Where is the Paraumbilical vein and what does it connect
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it runs in the falciform ligament and connects the left portal vein to the systemic epigastric vein near umbilicus
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If a patients hepatofugal flow in a patent paraumbilical vein exceeds the hepatopedal flow in the portal vein the patient may be
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protected from esophageal varices
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What is the sonographic appearance of splenorenal and gastrorenal collaterals
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tortuous veins which may be seen in the region of the splenic and left renal hillus
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The plenornal and gastrorenal veins represent collaterals between the
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splenic, coronary, and short gastric veins, and the left adrenal and renal veins
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The intestinal venous collaterals appear where? and what are they from
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the regions where the GI tract becomes retroperitoneal. veins of the ascending and descending color, duodenum, pancreas, and liver anastamose with the renal, phrenic, and lumbar veins
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Hemorrhoidal venous collaterals are where? and come from what?
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the perianal region where superior rectal veins anastamose with the systemic middle and inferior rectal veins
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You can't see the gastroesophageal varices but you will see an
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enlarged coronary vein
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Other liver problems associated with portal hypertension
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elevated LFT's
GI bleeding Jaundice Hematemesis |
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What is normal portal vein size?
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10-16mm
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Normal PV flow should be in the ______ direction
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hepatopedal
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The mean velocities of PV should be ____ and should vary with ____ and ____ _____
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15-20cm/s, respiration, cardiac pulse
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As hypertension develops the flow in the portal vein loses its respiratory variation and becomes
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monophasic
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As severity of PV hypertension increases flow becomes _____ and eventually _____
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biphasic, hepatofugal
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With patients with cirrhosis increased blood flow is noted in the ___ and _____ with ________
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splenic, SMA, splenomegaly
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If the right and left gastric veins are seen as collaterals they should be
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4-5mm diameter
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If esophageal vessels are collaterlized they will be best seen
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midline transverse angled cephalad through the left lobe
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If gastrorenal, splenorenal, and short gastric veins are collateralized then they will be best visualized
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transverse and sagittal near the splenic hilum
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PV thrombosis has been associated with malignancy including
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HCC, metastatic liver disease, pancreatic carcinoma, primary leiomyosarcoma
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PV thrombosis can be caused by
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Chronic pancreatitis, hepatitis, septicemia, trauma, splenectomy, portocaval shunts, hypercoagulable state, and pregnancies
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PV thrombosis in neonates can be caused by
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omphalitis, umbilical vein cathaterization, and acute dehydration
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What kind of hypertension is PV thrombosis?
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extra hepatic presinusoidal
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What are the symptoms of PV thrombosis
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ascites, splenomegaly, bleeding, varices
NO RUQ or jaundice |
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What are the sonographic findings for PV thrombosis>
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an absence of blood flow in the PV and the presence of thrombus, PV collateral, expansion of the caliber of the vein and cavernous transformation.
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What is a cavernous transformation
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numerous worm-like vessels at the portahepatis which represent periportal collateral circulation
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When is a cavernous transformation usually seen?
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in long standing thrombosis usually requiring up to 12 months to occur, making it more likely to develop with benign disease.
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Acute thrombosis may look ____ making it difficult to identify on 2D. What must you use to diagnose it?
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anechoic, use doppler
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How could doppler help distinguish benign from malignant portal thrombosis
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if thrombus is pulstatile it is malignant
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What is Budd Chiari Syndrome and what does it mean to us
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thrombosis of the hepatic veins with or without occlusion of the vena cava. we diagnose the degree of occlusion and presence of collaterals to predict clinical course
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Budd-Chiari is most common in
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India, South Africa, and Asia
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In North America Budd-Chiari is seen most often in
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Young women on birth control
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What is the symptoms of Budd-Chiari
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acute ascites, RUQ pain, hepatomegaly, and possibly splenomegaly
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What is the etiology for Budd-Chiari
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typically unknown
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What evaluations are done in order to assess Budd-Chiari
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b-mode
color doppler doppler |
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What does the liver present when affected by Budd-Chiari?
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acute: large and bulbous
infarction: significant regional echogenicity with fibrosis overtime |
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Why is the cuadate lobe typically spared in Budd-Chiari
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because it has emissary veins that drain directly into the vena cava at a lower level then the hepatic veins
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With Budd-Chiari if there is increased cuadate lobe blood flow it leads to
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cuadate lobe enlargement
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