Liver (part 2)

- congenital abnormalities & cystic disease of the liver

Agenesis of liver

absence of liver formation

accessory fissures of the liver

rare, caused by infolding of the peritonunem

liver vascular abnormalities

• arterial anatomy variation

• hepatic vein branch variation

• atresia

• stricture

• valve formation in portal vein

Partial Situs Inversus

only abdominal contents are in reversed positions

• liver is at LUQ instead of RUQ

Complete Situs Inversus

both chest and abdominal contents are in reversed positions

• Liver → LUQ

• Heart → right

Diaphragmatic hernia

an opening in the diaphragm that allows abdominal contents to move up into the thoracic cavity

Riedel lobe

• what is it?

• common in male or females?

• sono appearance?

• an extension of the right, inferior lobe of the liver below the lower pole of the right kidney

• common with women

• normal liver echotexture

• normal left lobe

• normal AP dimension of right lobe

How to differentiate a Riedel Lobe with hepatomegaly?

• compare the right lobe with the left lobe.

  • left lobe normal sized → Riedel

  • both left + right lobe enlarged → hepatomegaly

• measure AP liver dimension of right lobe

  • if WNL → Riedel

  • if enlarged → hepatomegaly

Extended left lobe

• where does it extend to?

• can be mistaken for what?

• sono appearance

• elongated left lobe that extends into the LUQ

• left lobe can be seen adjacent to medial and superior spleen

• left lobe extends anterolateral across AO to the LUQ

• can be mistaken for hepatomegaly

• normal echotexture

Liver Simple Cysts

• simple, anechoic

• asymptomatic

• common after age 50

• simple cysts before age 50

  • related to polycystic disease and cysts in the kidneys, pancreas and ovaries

• aspiration or ablation is performed for symptomatic patients

Liver simple cyst sono appearance

• smooth borders

• regular, well-cricumscribed walls

• anechoic, no internal echoes

• posterior enhancement

• through transmission

Liver hemorrhagic cysts

• blood leaks into an existing cyst

• thrombosis forms within the cyst

• pain secondary to hemorrhage / infection

• low hematocrit levels

Sono appearance of hemorrhaghic cysts

• thrombus causes irregular appearnce of internal echoes

• fluid/blood levels

• septations

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Polycystic Liver Disease (PCLD)

• what is it?

• are LFTs affected?

• common with what age?

• if pt is under 50 y/o, PCLD is associated with what?

• autosomal dominant disorder (one parent has the gene)

• multiple cysts that don’t communicate with biliary tree

• normal LFTs

• common age 30-40

• simple cysts before age 50

  • related to polycystic disease, along with cysts in the kidneys, pancreas, spleen, ovaries

polycystic liver disease sono appearance

• focal cystic areas

• varied sizes

• thin septations

• evaluate pancreas, kidney, spleen, ovaries for cysts

biliary hamartomas (von Meyenburg complexes)

• focal developmental lesions of the liver

• composed of groups of dilated intrahepatic ducts within dense stroma

Biliary hamartomas sono appearance

• small nodules

  • echogenic

  • causes diffused heterogeneous appearance of liver tissue

• multiple, well-defined, solid nodules < 1 cm diameter

• large nodules → hypoechoic

• echogenic foci with comet tail / ring down artifact

• twinkle artifact

• associated with congenital hepatic fibrosis, autosomal dominant polycystic disease, cholangiocarcinoma

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Fatty Infiltration of the Liver (steatosis)

• triglyceride accumulation in the liver cells

• reversible

• most common cause = obesity

What are the 2 types of Fatty Liver Disease?

• causes?

• what can they lead to?

• what LFTs are affected?

• alcoholic fatty liver disease

  • caused by chronic alcohol intake

  • can lead to alcoholic hepatitis

  • increased AST, ALT

• non-alcoholic fatty liver disease

  • caused by diabetes, obesity, TB, cystic fibrosis, starvation, steriod use

  • can lead to NASH (nonalcoholic steatohepatitis)

  • mild, moderate increase of AST, ALT

Distribution of Fatty Liver Disease

• diffuse replacement = entire liver is fatty

• focal fatty sparing = entire liver involved except localized areas

• focal fatty replacement = small portion of the liver experiences fatty infiltration

Diffuse infiltration of fatty liver

• mild = slight increase in fine echoes, normal visualization of diaphragm and vessel borders

• moderate = moderate increase in fine echoes, impaired visualization of the diaphragm and vessel borders

• severe = marked increase in fine echoes, poor or non-visualization of the diaphragm and vessel borders

• Hepatomegaly > 15.5 cm

• Hepatic vasculature is not displaced with fatty replacement, but flow changes can occur

• hepatic veins can be narrowed due to fatty liver changes with decreased outflow, loss of pulsatility and respiratory phasicity; monophasic antegrade waveform

focal infiltration of fatty liver

• focal area of increased echogenicity

• irregular borders

• adjacent to portal structures

• looks like hemangiomas

• does NOT displace surrounding structures

Focal sparing of fatty liver

• focal area of decreased echogenicity with remaining liver tissue diffusely increased in echogenicity

• irregular borders

• adjacent to GB fossa

• similar appearance to malignancy

• does NOT displace surrounding structures

liver changes with alcoholism

normal → steatosis → fibrosis → cirrhosis

• liver becomes smaller, increased heterogeneous echotexture and coarse

mild steatosis

moderate steatosis

severe steatosis

How to differentiate betweem a hemangioma and fatty infiltration?

• hemangiomas will cause a mass effect and displace surrounding structures, while fatty infiltration will not affect surrounding structures.

Reye Syndrome

• what is it and how does it look like on US

• how does it develop?

• rare disorder that affects children

• develops during recovery from a viral infection like chicken pox, flu

• associated with taking aspirin during viral infection

• sono appearance - looks like steatosis (fatty liver)

  • hepatomegaly

  • fatty infiltration

Reye Syndrome Symptoms

• what are they?

• what can this syndrome result in?

• symptoms:

  • increased cranial pressure

  • abnl LFTs

  • excessive vomiting

  • confusion

  • delirium

  • loss of consciousness

  • seizures

• can result in lasting brain damage and/or death

Amyloid disease

• deposition of amyloid protein within the vessel walls of various organs which leads to organ failure

Glycogen storage disease

• Autosomal recessive disorder

• Type 1 most common (von Gierke disease)

• Affects liver and skeletal muscle

• Labs = hypoglycemia, or abnl LFTs

• Excessive storage of glycogen within hepatocytes - hepatomegaly, increased echogenicity, associated with adenomas

• Reduced storage - hypoechogenicity

• Prominent portal walls

Starry sky (similar to acute hep)