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113 Cards in this Set
- Front
- Back
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What percent of the population has liver cyst
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14%
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Describe the margin and shape of a benign liver cyst
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round/ovid with sharp margins
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What are the signal characteristics of a benign liver cyst on MR
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low T1
high T2 |
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should you be able to see the wall of a liver cyst
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no
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can liver cyst have a hemorraghic component
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yes rarely but more common in polycystic liver
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What is the DDX for t2 bright liver lesions
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cystic mets
carcinoid hemangioma biliary cystadenoma bilary cystadenomcarcinoma |
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Do biliary cystadenocarcinoma and cystadenoma typicaly have septae and are large in size
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yes
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Do all cystic mets enhance
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no
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What is a way to differentiate a simple cyst from neoplastic
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close followup
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Where are hemangiomas more common; the left or right lobe
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right
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What percent of the population have hemangiomas
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7-20%
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What is the typical enhancement pattern of a hemangioma
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interrupted peripheral nodular enhancement
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Does enhancement follow the blood pool in hemangiomas
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yes
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Do all hemangiomas fill in completely
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no, if the lesion is large and there is a central scar it may not
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What is the T2 signal characteristic of a hemangioma
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almost as bright as a cyst
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What is the ddx of a t2 bright liver lesion
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hypervascular tumor
cystic met |
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How do you tell that sequence is delayed enhancement by looking at the renal collecting system
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gad is dark in the collecting system
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Do you see peripheral enhancement with very small hemangiomas
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no
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Do small hemangiomas have delayed washout
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yes, differentiates from a met
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What is the ddx for interrupted peripheral nodular enhancement
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treated mets
hemangioendothelioma angiosarcoma |
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What demographic will get hemangioendothelioma
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pediatric
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if there is a lesion in a pediatric pt that has nodular enhancement and capsular retraction what should you think about
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hemangioendothelioma
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Where do angiosarcomas occur
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lung, spleen, liver
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What does the periphery of angiosarcoma look like
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nodular heterogenous enhancement (not as nice looking as a hemangioma)
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Where does focal fat occur
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falciform ligament
GB fossa |
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What happens to focal fat in the out of phase imaging
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it will loss signal (has microscopic fat)
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What are 2 characteristic of focal fat
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no mass effect
non-displaced vessels coarse through |
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What is the appearance of a fat sparring region in the liver
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fat sparring
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What percent of FNH occurs in young women
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80-95%
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What percent of FNH are solitary
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80%
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What is the typical contour and location of FNH
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lobulated
liver periphery |
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What are the MR characteristics of FNH
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iso to low on T1
iso to high on T2 (similar to liver parenchyma bc it is hyperplasia so similiar signal characteristics) |
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What percent of FNH have a central scar
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50-75 percent
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What is the MR characteristics of the central scar of fnh
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low t1
high t2 |
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Does the non-central scar portion of a FNH enhance homogenously
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yes (helps differentiate from an adenoma)
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When does the scar of fnh enhance
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delayed phase
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What is the ddx of liver lesion with central scar
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hepatic adenoma
large hemangioma fibrolamellar hcc |
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What nuc med scan can be used for fnh
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sulfur colloid
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What is the typical age group of fibrolamellar hcc and fnh
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fibrolamellar hcc- adolescent and young adult
FNH- 30-40 |
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What is age group of a large hemangioma
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40-50
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What is the order of frequency of fnh, adenoma and fibrolamellar hcc
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fnh>adenoma> fibrolamellar
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Should you ever diagnose fnh in the context of underlying liver disease
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no
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What drug is hepatic adenomas associated with
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OCP
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What are the MR characteritics of an adenoma
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heterogenous T1 and T2
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What causes the heterogenous appearance of an adenoma
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fat/ hemorrhage
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What are the malignant lesions of the liver
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mets
hcc cholangioCA |
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What is more common a hypodense or hyperdense met to the liver
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hypodense
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What is the typical mr characteristics of mets of the liver
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T1 bright (not as bright as tumor)
T2 dark |
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Liver mets enhancement pattern
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early arterial enhancement
low signal portal venous phase |
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What causes cystic change in a metastatic liver lesion
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necrosis from rapid cell turnover which outstips the blood supply
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Are cystic mets common
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no
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What are common primaries of cystic mets
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mucinous adenocarcinoma
colorectal ovarian |
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What do you usually see in the periphery of a cystic met during arterial phase
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a ring of enhancement
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What two primaries cause calcificed liver mets
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serous ovarian carcinoma
mucin producing colorectal |
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What is the DDX for hypervascular liver mets
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neuroendocrine tumors
thyroid sarcoma RCC |
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Name 3 neuroendocrine tumors
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islet cell
carcinoid pheochromocytoma |
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Name 4 predisposing factors to HCC
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alcoholic cirrhosis
Hep C hemachromatosis glycogen storage disease |
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What percent of HCC have some high T2 signal
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90 (usualy heterogenous)
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What are the components of HCC that cause heterogenous T1 and T2 signal
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fat, necrosis, hemorrhage,
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Most HCC will be T1 dark but what percent are T1 high and why
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30%
copper, hemorrhage, fat |
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What is the measurement that a lesion must be to acurately diagnose as HCC
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2 cm, if it is less follow up or biopsy
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What happens to HCC on the venous phase
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wash out will occur
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Can HCC be infiltrating
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yes
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should you automaticaly suspect LN spread if there is a solitary LN that is 2cm in a patient with HCC
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no, bc these pt have underlying dz and it may be reactive. you look for a group of enlarge nodes
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Does HCC invade vessels
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yes
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How do you differentiate between bland tumor and tumor thrombus
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expansion of the vessel
arterial phase enhancement |
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What should be done if a patient has a cirrhosis and you see lesioon suspicios for HCC that is 1.5 cm
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follow up closely
cant diagnose unless 2cm or greater |
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What is a pitfall for diagnosing HCC in a pt with bud chiari
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benign hyperplastic regenerative nodules that enhance. This is specific to bud chiari
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What is the 2nd mc liver primary
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cholangiocarcinoma
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What is the enhancement pattern of cholangioCA
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delayed
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Does cholangioCA cause capsule retraction
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yes
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What are predisposing factors to cholangioCA
5 |
PSC
Caroli dz choledochal cyst thorotrast Parasites |
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What may happen to the wall of the bile duct and the intrahepatic ducts
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the bile duct wall becomes thickened
the intrahepatic ducts dilate |
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What are the 3 patterns of cholangioCA
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mass forming
infiltrating (periductal) Intraductal |
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What are the MR signal of cholangioCA
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Fluid
high T2 low T1 |
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What causes the nodularity of the liver in cirrhosis
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regenerative nodules
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What are the earliest segments to undergo retraction in cirrhosis
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anterior segment of the right lobe and the medial segment of the left lobe
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What is the signal characteristics of regenerating nodules
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low T1 and T2
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What 2 metals are found in regenerative nodules
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iron and copper
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What is a siderotic nodule
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a nodule that contains iron
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In addition to the right lobe, does the medial segment of the left lobe undergo atrophy
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yes
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What happens to the caudate lobe and lateral left in cirrhosis
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hypertrophy
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What is the radiographic difference between a dysplatic nodule an regenerativ nodule
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little. this is a differnence in the amount of atypia
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What is important to do if there is a suspiciious RN
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follow up
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How is RN different from DN (change prior slide)
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DN is classicaly bright on T1,
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What are the signal characteristics of fibrosis
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low on T1
high on T2 |
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Does fibrosis enhance
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minimally
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What does fibrosis in cirrhosis look like
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ill defined, patchy
thin or thick band perivascular cuffing (in PBC) |
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Where is focal confluent fibrosis seen
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anterior segment of right lobe
medial segment of the left lobe |
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What is the shape of confluent fibrosis
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wedge (may involve an entire segment)
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What is the ddx of focal confluent fibrosis
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HCC (bc its T2 bright)
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How are varices of the GE junction formed
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back up through the coronary vein and short gastrics to the systemic drainage of esophagus
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How are paraumbilical varices formed
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back up through the left portal and paraumbilical to epigastric veins
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What is the ddx of cause of fatty infiltration of the live
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obesity
TPN alcohol pregnancy steroids chemotherapy malnutrition |
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What is the hounsfield measuremnt used to determine faty liver on NECT
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liver is 10hu less than the spleen and darker it is fatty
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how do you determine if a liver is fatty on MR
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Out of phase GRE loss of signal
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What is hemochromatosis
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autosomal recessive condition with abnormal Fe absortion from the GI tract
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Where does the iron deposit in primary hemochromatosis
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liver
pancrease heart joints endocrine glands skin |
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What does the liver look like on T2 in a pt with hemochromatosis
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dark
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What do you use to compare to if you suspect hemochromatosis on T2 t
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the paraspinal muscles
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What does hemochromatosis do to the liver
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increased density (70-120 hu)
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What are causes of diffuse increased density of the liver
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amiodarone (look for pacer)
hemochromatosis wilson glycogen storage thorotrast |
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What is the cause of hemosiderosis
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dyserythropoesis
transfusions |
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where does the iron of hemosiderosis accumulate
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the Reticuloendothelial system only (liver, spleen, bone marrow)
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What is the signal of T2/T2*/T1 GRE in hemochromatosis
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dark
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What is the MCC of bud chiari
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idiopathic
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What is THAD
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transient hepatic attenuation differences that is do to local decrease in PV perfusion and increased hepatic artery perfusion
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When do you see THAD
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PV thrombosis
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When are the two times you see THAD
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lobar late arterial
Early PV attenuation |
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Is hepatic infarction common
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no
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What is hepatic infarction associated with
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liver transplant
cholecystectoma hepatic artery occusion shock, sepsis vasculitis eclampsia OCP |
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What do you see in hepatic infarction
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geographic areas of low attenuation
acites atrophy and necrosis later |
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What are the MR characteristics of hepatic infarction
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Low T1
High T2 |
