Liver Flashcards
What are some conditions that can be evaluated using liver ultrasound?
Cirrhosis Liver failure Portal hypertension Tumors Abscesses Traumatic injury
Why is the liver a useful sonographic window?
It has high fluid content and natural homogenous parenchyma
What is the connective tissue surrounding the liver called?
Glisson’s capsule
What type of structure is the liver?
Intraperitoneal
Where is the liver located?
Right upper quadrant
Inferior and posterior to the diaphragm and moves with it during respiration
Anatomic right of stomach
What are the three structures that comprise the portal triad?
Hepatic artery, common bile duct, portal vein
How is the liver measured?
From inferior tip of dome and along the midclavicular line
What is the maximum normal size of the liver?
16 cm
What do the walls of the hepatic veins look like?
They are thin and dull
What do the walls of the portal vein and hepatic artery look like?
They are thick and echogenic
What transducers are preferred for liver scanning?
Low frequency 5-2.5 mHZ with curvilinear probe
What may be needed to scan the liver between the ribs?
Phased array
How long should a patient be NPO?
8 hours
How should a patient be positioned for a liver scan?
Supine or left lateral decubitis
How do you optimize liver images?
Deep breaths
What surfaces of the liver are in contact with the diaphragm?
Superior and anterior
What are useful approaches in liver sonography?
TA sagittal and transverse
Intercostal
Subcostal
How do hepatic ligaments appear?
Hyperechoic relative to surrounding parenchyma
What classification divides the liver into segments
Functional or Couinaud
What does each liver segment possess a branch of?
Portal vein
Hepatic artery
Hepatic vein
Bile duct
What are characteristics of doppler mode imaging?
Color flow provides information regarding the liver
Pulsed wave is useful in evaluating portal hypertension
How does the HA supply the liver?
With oxygenated blood
Hepatopedal
How does the PV supply the liver?
Afferent blood flow from intestines
Hepatopedal
What forms the main portal vein?
Splenic and superior mesenteric veins
What describes HV flow?
Drain deoxygenated blood into IVC
Hepatofugal
What liver characteristics should be studied and documented?
Contour, echogenicity, and vascularity
What does the bile duct look like on US?
Hyperechoic walls and lumen w no color flow
What does the HV look like on color doppler?
Thin walls w lumen that has flow
What does the HA look like on pulsed wave doppler?
Hyperechoic walls w pulsatile flow
How do you differentiate portal and hepatic veins?
Tracing path of HV back to IVC
Where is the diaphragm in regards to the liver?
Superior w hyperechoic border
Where is the potential space for intraperitoneal fluid accumulation?
In front of Morison’s pouch
Between liver and RT kidney
Where does the HV return blood to?
IVC
What does the main lobar fissure connect?
Gallbladder and portal vein
How do we improve liver imaging?
Pt fast 8 hours
Deep breath and hold
Raise RT elbow over head
Left lateral decubitus
What is the normal sonographic appearance of the liver?
Homogenous parenchyma with mid-grey color
Isoechoic to renal cortex
Hypoechoic to spleen
Vessels and ducts that are anechoic w bright walls
What surrounds the liver?
Glisson’s pouch
What is the largest parenchymal organ in the body?
The liver
What are some functions of the liver?
Produces and secretes bile
Synthesizes clotting factors
What structures should you capture on liver ultrasound?
IVC, HV, PV & branches w color
Right, left, caudate lobes
What axis should the liver be measured in?
Longitudinal
What can we use as a comparison when evaluating liver echogenicity?
Right kidney
What are the four lobes of the liver?
Right, left, caudate, quadrate
What is a remnant of the umbilical vein?
Ligamentum teres
What does the main lobar fissure separate?
Right and left hemiliver lobes
Where does the main lobar fissure run?
From gallbladder through IVC to caudate lobe
What vessel carries the greatest percentage of total blood flow to the liver?
Portal vein
75%
What vessels form the portal vein?
Splenic vein and superior and inferior mesenteric veins
What do the splenic and superior and inferior mesenteric veins empty?
Spleen, gallbladder, pancreas, GI tract
What are normal flow patterns of HV?
Hepatofugal
Pulsatile
Multiphasic
What are normal flow patterns of HA?
Hepatopedal
Low resistant
What are normal flow patterns of PV?
Hepatopedal
Continuous flow
Moderate pulsatility
What is the metabolic function of the liver for carbs?
Conversion of dietary sugars into glucose
Excess glucose into glycogen and stored
Glycogen back to glucose
Why can liver disease lead to hypoglycemia?
It prevents the liver from making enough glucose
Glucose deficiency
Why can liver disease lead to hyperglycemia?
Liver may fail to convert excess glucose into glycogen
What is the metabolic function of the liver associated with fats?
Metabolism of fats
Dietary fats to lipoproteins
Converts fats to energy
What is fatty liver?
Nonspecific finding
Manifestation of many kinds of hepatocellular disease
What may fatty liver disease be associated with?
Hepatitis Alcoholic liver disease Obesity Diabetes Pregnancy Chemical exposure
What is the metabolic function of the liver with proteins?
Produces proteins from amino acids and raw materials
Produces albumin
Produces fibrinogen and thrombin for coagulation
Why can liver disease cause edema?
Loss of vascular osmotic pressure causes fluid build up in interstitial space
What is the principal cause of ascites development?
Portal hypertension
Why can liver disease cause hemorrhage?
Decreased production of thrombin and fibrinogen needed for clotting
What are hepatic enzymes?
Protein catalysts that leak into bloodstream when liver cells are damaged or destroyed
What is the detoxification function of the liver?
Detox waste products of energy production
Breaks down foreign chemicals
Why would a Pt with severe liver disease have fruity or pungent breath?
Because of an ammonium concentration
Why is failure of ammonium detox serious?
If not detoxified by the liver, it can cause coma or death from blood loss
Describe uptake of bilirubin
Bilirubin separated from albumin and taken by hepatocytes
Describe conjugation of bilirubin
Bilirubin molecule combined with glucuronide
Describe excretion of bilirubin
Bilirubin released from hepatocytes, goes through bile ducts to bowel
What is bile?
The excretory product of the liver formed by hepatocytes
What is the function of bile?
Emulsification of fat
Removal of waste products from bile excretion
What causes echogenic bile?
Stasis
Decreased bile from the liver
What is aspartate aminotransferase? AST
Enzyme found in tissues w high metabolic rate
What are pathologies associated w AST?
Acute hepatitis
Cirrhosis
Hepatic necrosis
Infectious mononucleosis
What is alanine aminotransferase? ALT
Enzyme found in tissues w high metabolic rate
What are pathologies associated w ALT?
Acute cirrhosis Hepatic metastasis Pancreatitis Infectious or toxic hepatitis Hepatocellular disease
Where is lactic acid dehydrogenase found?
Liver, kidneys, skeletal muscle, brain, lungs
What are pathologies associated with lactic acid dehydrogenase?
Hepatitis
Cirrhosis
Obstructive jaundice
What is alkaline phosphatase?
Enzyme produced by liver, bone, intestines, and placenta
What are pathologies associated with alkaline phosphatase?
Intra or extrahepatic obstruction
Hepatic carcinoma
Abscess
Carcinoma
What is bilirubin a product of?
Hemoglobin breakdown of tired red blood cells
What is direct bilirubin?
Conjugated
What is indirect bilirubin?
Unconjugated
What is prothrombin?
Liver enzyme that plays a part in blood clotting mechanism
What is albumin?
Serum used to detect protein synthesis levels
Low albumin, low PS
What is globulin?
Used to show chronic liver diseases
Elevated globulin = CLD
What are indications for a liver scan?
Elevated LFT
Prior dx of hepatitis, cirrhosis, hepatic steatosis
Hepatomegaly
Mass near or in liver
