Imaging Procedures HEPATOBILIARY Flashcards

1
Q

What’s the whole goal in using MDCT for hepatobiliary evaluation

A

look for and characterize liver lesions

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2
Q

How does IV contrast help in MDCT hepatobiliary evaluation

A

differentiates between lesions and normal liver tissue

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3
Q

indications for non contrast imaging of the liver

A
  • look for hemorrhage
  • fatty infiltration
  • liver calcification
  • characterize lesion enhancement
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4
Q

hypo dense, hyper dense, iso-dense, hypo vascular, and hyper vascular are terms used to describe what ?

A

hypo dense &hyper dense: Describes density of soft tissue masses in relation to their surroundings

hypo vascular & hyper vascular: tumor vascularity

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5
Q

Unenhanced liver tissue has a CT density range of what?

Is its density greater or leas than blood vessels and spleen tissue ?

A

45-65 HU

greater

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6
Q

T/F . Hepatic mets are usually hyperdense.

A

F.

Hypodense

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7
Q

Tumors with densities equal to that of surrounding tissue are termed:

Give example

A

iso-dense

HCCs

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8
Q

3 Examples of hyper-vascular tumors

A
  • HCC’s -Hepatocellular carcinoma’s
  • FNH’s- Focal Nodular Hyperplasia’s
  • hyper-vascular mets
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9
Q

What technique can help you better visualize iso-dense tumors like HCCs

A

scanning during multiple phases of enhancement

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10
Q

Which growths are benign ? Malignant ?

Hepatocellular Carcinoma, Hemangioma, Focal Nodular hyperplasia, metastases, hepatic cyst

A

Benign

  • Focal nodular hyperplasia
  • cysts
  • hemangioma

Malignant

  • HCC’s
  • Metastases
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11
Q

Benign tumor characterized by peripheral globular enhancement

A

Hemangioma

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12
Q

Benign tumor located on liver surface. Has intense homogenous enhancement

A

Focal nodular hyperplasia

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13
Q

Benign tumor. Distinguished by thin , round/oval shape. Attenuation equal to water

A

hepatic cyst

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14
Q

The most common primary malignant growth

A

HCC

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15
Q

This tumor appears hyper dense during arterial imaging and hypo dense during noncontract scanning

A

HCC

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16
Q

Primary tumors that - commonly metastasize to the liver typically come from where ( list 5)

A
stomach
colon 
lung 
pancreas 
breast
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17
Q

What is steatosis ?

A

A fatty liver

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18
Q

Indications for a MDCT scan of the liver

A
  • liver disease thats spread
  • trauma
  • infection
  • preop / post op
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19
Q

Two examples of diffuse liver disease

A

steatosis (fatty liver)

cirrhosis

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20
Q

Two causes of liver cirrhosis

A

alcoholism

hepatitis

21
Q

chronic disease characterized by portal hypertension , enlarged lobes, and invading fatty substance

A

cirrhosis

22
Q

chronic disease that makes the liver appear less dense than the spleen

A

steatosis

23
Q

Most commonly injured organ in trauma

second most common

A

spleen

liver

24
Q

Describe the dual blood supply of liver

A

75% from hepatic portal vein

25% hepatic artery

25
Q

What are the four phases of contrast enhancement in the liver

A

arterial
portal venous
equilibrium

26
Q

what time frame (seconds) is associated with each enhancement phase of the liver

  • arterial
  • portal venous
  • equilibrium
A
  • arterial 25-35 sec
  • portal venous 60-70 sec
  • equilibrium 2-3 min
27
Q

Hypervascular tumors are maximally enhanced at this phase

A

arterial

28
Q

hypovascular lesions are maximally enhanced at this phase

A

portal venous

29
Q

contrast enhancement begins to dissipate and you cant tell the difference between lesions and vasculature at this phase

A

equilibrium

30
Q

What’s the time difference between an arterial and early arterial phase

A

early arterial
15-20 after contrast admin

arterial
25-35 seconds after

31
Q

which phase occurs 5-20 mins after contrast admin?

What is the purpose of this phase during MDCT of the liver?

A

delay

represents complete fill of hemangioma

32
Q

3 factors that influence the timing of hepatobiliary phases

A
  • cardiac output
  • injection duration
  • Iodine [C]
33
Q

What is the benefit of scanning the liver in multiple phases

A

improves visualization of hypo and hyper vascular lesions

34
Q

The degree of liver tissue enhancement depends on what ?

A

dose of iodine delivered

35
Q

T/F reduced cardiac output has no effect on peak arterial and tissue enhancement

A

false . Delays enhancement

36
Q

How does a rapid injection rate benefit enhancement phases in the liver

A

provides more temporal separation between arterial and venous phases

37
Q

Give example of increasing iodine dose both directly and indirectly

A

directly: use contrast with higher iodine [C]
indirectly: use higher flow rate

38
Q

T/F. it is important to scan the liver during the highest level of contrast enhancement

A

True

39
Q

Describe gallbladder appearance on CT

A

oval sac, along inferior surface of the liver , within a fossa

40
Q

The CT density of the gallbladder is near that of what substance ?

A

water

41
Q

difference between cholelithiasis and cholecystitis

A

cholelithiasis is otherwise known as gall stones

the other is inflammation of the gallbladder

42
Q

How do calcified vs cholesterol vs mixed composite gall stones appear on a ct

A

calcified stones: easier to see
cholesterol stones: less density than bile

mixed composition: obscured on image

43
Q

3 parts of the biliary tract

A

common hepatic duct
common bile duct
intrahepatic bile duct

44
Q

What initial step can be used to look for gall stones

A

pre contrast image

45
Q

what can be used to eliminate streaking artifact from positive contrast in duodenum

A

water

46
Q

size of thins needed fro optimal images of GB and biliary tree

A

0.5 - 2 mm

47
Q

indications for biliary tree CT

A

bile duct stones

inflamed bile duct

neoplasm in BD

dilated or blocked duct

48
Q

what is choledocholithiasis?

cholangitis ?

A

bile duct stones

inflamed BD