chapter 2: the liver

what is the largest parenchymal organ in the body?

the liver

where is the liver located in the body?

the majority of it, the right lobe is located in the RUQ whereas the left lobe is located within the epigastrium and may traverse the midline and extend into the left hypochondrium

vital functions of the liver include:

• carb metabolism

• lipid metabolism

• amino acid metabolism

• removal of waste products

• vitamin and mineral storage

• drug inactivation

• synthesis and secretion of bile

• blood reservoir

• lymph production

• detoxification

low albumin is associated with what abnormalities?

• chronic liver disease

• cirrhosis

elevated ALP is associated with what abnormalities?

• cirrhosis

• extrahepatic biliary obstruction

• gallstones

• hepatitis

• metastatic liver disease

• pancreatic carcinoma

elevated ALT is associated with what abnormalities?

• biliary tract obstruction

• hepatitis

• hepatocellular disease

• obstructive jaundice

elevated AST is associated with what abnormalities?

• cirrhosis

• fatty liver

• hepatitis

• metastatic liver disease

elevated gamma-glutamyl transferase is associated with what abnormalities?

• diffuse liver disease

• posthepatic obstruction

elevated lactate dehydrogenase (LDH) is associated with what abnormalities?

• cirrhosis

• hepatitis

• obstructive jaundice

elevated serum bilirubin is associated with what abnormalities?

• Unconjugated (direct) bilirubin: acute hepatocellular disease

• Conjugated (indirect) bilirubin: biliary tract obstruction

• Total bilirubin: cirrhosis, hepatitis, and other liver cell diseases

prolonged prothrombin time (PT) is associated with what abnormalities?

• metastasis of the liver

• hepatitis

shortened PT is associated with what abnormalities?

extrahepatic duct obstruction

elevated AFP is associated with what abnormalities?

• hepatocellular carcinoma (hepatoma)

• hepatoblastoma

is the liver a retroperitoneal or intraperitoneal organ?

it is intraperitoneal

the bare area of the liver includes:

• the area of the falciform ligament

• gallbladder fossa

• porta hepatis

• an are adjacent to the IVC

what are the 3 main hepatic lobes?

• right

• left

• caudate

what do the lobules of the liver contain?

• hepatocytes

• biliary epithelial cells

• Kupffer cells

sonographically, the quadrate lobe is referred to as the:

medial segment of the left lobe and is NOT considered one of the main hepatic lobes

the right hepatic vein and the right intersegmental fissure separate the:

anterior segment of the right lobe from the posterior segment of the right lobe

the middle hepatic vein, main lobar fissure and gallbladder fossa separate the:

right lobe from the left lobe

the left hepatic vein, left intersegmental fissure, ligamentum teres and falciform ligament separate the:

left lateral segment of the left lobe from the left medial segment of the left lobe

the right lobe can be divided into an anterior and posterior segment by what vessel?

the right hepatic vein

the right hepatic vein lies in what fissure?

within the right intersegmental fissure

the right lobe can be separated from the left lobe by what vessel?

the middle hepatic vein

the middle hepatic vein lies in what fissure?

within the main lobar fissure

the left lobe of the liver may be divided into a medial and lateral segment by what structures?

• the left hepatic vein

• the ligamentum teres

• falciform ligament

the left hepatic vein lies in what fissure?

within the left intersegmental fissure

the caudate lobe is bounded anteriorly by:

the ligamentum venosum

the caudate lobe is bound posteriorly by:

the IVC

what vessel supplies the liver with the majority of blood?

the main portal vein

where does most of the blood in the main portal vein originate from?

from the intestines

doppler characteristics of the portal veins:

• hepatopetal

• monophasic with some variation with breathing

function of the portal veins:

transports blood to the liver from the intestines and other organs

location of the portal veins:

• main portal vein enters the liver at the porta hepatis

• intrasegmental

number and pattern of the portal veins:

• main portal vein branches into left and right

• decrease in size as they approach the diaphragm

sonographic appearance of the portal veins:

hyperechoic walls

doppler characteristics of the hepatic veins:

• hepatofugal

• triphasic

function of the hepatic veins:

drain blood from the liver and deposits it into the IVC

location of the hepatic veins:

• upper aspect of the liver

• intersegmental

• interlobar

number and pattern of the hepatic veins:

• 3 → right, middle and left (some ppl may have extra)

• increase in size as they approach the diaphragm

sonographic appearance of the hepatic veins:

thin walls → perpendicular incidence may cause a brighter appearing wall

what are the primary vessels of the splanchnic circulation?

• celiac artery

• SMA

• IMA

the main portal vein is created by the union of what vessels?

by the union of the SMA and splenic vein → portal confluence/portal splenic confluence/portovenous confluence

normal AP diameter of the main portal vein:

< 13 mm (1.3 cm)

what happens to the blood flow in the portal vein after a meal?

it will demonstrate an increase in flow (becomes more low resistance)

the main portal vein branches into the:

right and left portal veins

the right portal vein branches into the:

anterior and posterior right hepatic veins

the left portal vein branches into the:

medial and lateral left portal veins

function of the common hepatic artery:

carries oxygenated blood to the liver from the abdominal aorta

the common hepatic artery is a branch of what vessel?

a branch of the celiac artery

what type of flow does the common hepatic artery demonstrate?

low resistance flow

the “Mickey” sign describes:

the transverse image of the porta hepatis → MPV, CBD and hepatic artery

what is the echogenicity of the ligaments in the liver?

hyperechoic

the ligamentum venosum is located:

anterior to the caudate lobe, between the caudate lobe and the L hepatic lobe

the falciform ligament is located:

near the L portal vein

diaphragmatic slip

occurs in older pts and is caused by hypertrophied diaphragmatic muscle bundles

sonographic appearance of a diaphragmatic slip:

hyperechoic strands extending from the diaphragm in the sag plane

a Riedel lobe is more often seen in what population?

in women

if the entire RUQ is to be evaluated, how long should the pt fast before the exam?

8 hrs

sonographic characteristics of a normal liver:

• homogeneous

• echogenicity equal or slightly greater than the parenchyma of the normal R kidney and slightly less echogenic than the spleen

normal length measurement of the liver:

13-15 cm

the most accurate measurement of the right lobe can be obtained:

from the uppermost right hemidiaphragm to the inferior tip of the right lobe using a horizontal plane parallel to the anterior liver wall through the midaxillary line

what vital laboratory test should be assessed before conducting a RUQ sonogram?

serum bilirubin test

prehepatic jaundice can be caused by:

sickle cell disease

hepatic jaundice can be caused by:

• viral hepatitis

• toxins

• drugs

• cirrhosis

• liver cancer

posthepatic jaundice can be caused by:

obstruction to bile flow typically by either a gallstone or pancreatic mass