Chapter 26 - Liver, Biliary Tree and Gallbladder (CHERI NOTES) Flashcards
__ is the current method of choice for most hepatic imaging.
(p.692)
DYNAMIC BOLUS CONTRAST-ENHANCED MDCT
___ is used as a screening method for patients with abdominal symptoms and suspected diffuse or focal liver disease. (p.692)
ULTRASOUND
___ are used to assess hepatic vessels and tumor vascularity.
(p.692)
COLOR FLOW and SPECTRAL DOPPLER
____ is used in the characterization of cavernous hemangiomas
and focal nodular hyperplasia. (p.692)
RADIONUCLIDE IMAGING
MDCT of the liver is performed using a ___ or ___ protocol
of multiple scans of the entire liver. (p.692)
THREE-PHASE or FOUR-PHASE
Maximum enhancement of the liver is attained during the ___ phase to demonstrate hypovascular lesions as low-attenuating masses on a background of brightly-enhanced parenchyma. (p.692)
PORTAL VENOUS phase
2/3 of the hepatic blood supply comes from the ____. (p.692)
PORTAL VEIN
maximum enhancement of the liver parenchyma occurs at
____ to ___ seconds following hepatic arterial enhancement.
(p.692)
60 to 120 seconds
Delayed images are obtained several minutes after contrast
injection to document late-contrast fill-in of _____ and
delayed enhancement of ____. (p.692)
HEMANGIOMA and CHOLANGIOCARCINOMA
Gadolinium-based contrast agent which is akin to
iodine-based contrast agents used in CT. (p.692)
Gadopentetate dimeglumine (Magnevist)
Liver-specific contrast agents such as ____ have conventional properties of the extracellular agents as well as being taken up by hepatocytes; which improves the detection and
characterization of small lesions. (p.692)
Gadoxetate disodium (Eovist)
_____ emerged as a method of hepatic lesion detection and
characterization in patients who cannot receive IV contrast.
(p.692)
DIFFUSION-WEIGHTED MR
____ is used for quantitation of liver fatty infiltration and other diffuse hepatic diseases. (p. 692)
MR spectroscopy
____ is used as a rapid screening modality to detect diseases
of the liver; biliary tree and gallbladder. (p.692)
ULTRASOUND
Radionuclide imaging of liver offers functional information
in characterizing lesions such as ____. (p.692)
FOCAL NODULAR HYPERPLASIA
_______ is very useful for definitive diagnosis of
cavernous hemangioma. (p.692)
RADIONUCLIDE BLOOD POOL IMAGING
Transient enhancement difference are seen during either
____ phase imaging or ____ phase imaging on MDCT and
dynamic MR. (p.694)
ARTERIAL phase imaging or
PORTAL VENOUS phase imaging
meaning of the acronyms THADs or THIDs (p.694)
TRANSIENT HEPATIC ATTENUATION DIFFERENCES or
TRANSIENT HEPATIC INTENSITY DIFFERENCES
-this results in focal areas of increased or decreased enhancement during the various phases of the parenchymal enhancement.
Portal venous flow may be altered by these three causes.
p.694
- PORTAL BLOCKADE BY TUMOR OR THROMBUS
- EXTRINSIC COMPRESSION CAUSED BY RIBS OR DIAPHRAGMATIC SLIPS; OR TUMORS OF THE LIVER CAPSULE
- THIRD INFLOW from systemic veins in the pericholecystic; parabiliary; and epigastric-paraumbilical venous systems.
Systemic venous blood drains into ___ altering normal intrahepatic blood flow. (p.694)
HEPATIC SINUSOIDS
On CT, the attenuation of normal liver parenchyma is ____ than the attenuation of normal spleen parenchyma on unenhanced images. (p.694)
EQUAL TO OR GREATER THAN
-following bolus IV contrast administration; the normal parenchymal enhancement is less than that of the spleen during arterial phase; and equal to or greater than that of the spleen during the portal venous phase.
On MR T1WI; the normal liver is slightly higher signal intensity than the ____; and most focal lesions appear as lower-intensity defects.
SPLEEN
- with T2WI; the normal liver is less than or equal to the spleen in signal strength; and most lesions appear as high-intensity foci.
2 evidences of HEPATOMEGALY. (p.694)
- Rounding of the inferior border of the liver
2. Extension of the right lobe of the liver inferior to the lower pole of the right kidney.
A liver length greater than ___ cm; measured in the midclavicular line; is considered enlarged. (p. 694)
greater than 15.5 cm
______ is normal variant of hepatic shape found most often in women. It refers to an elongated inferior tip of the right lobe of the liver. (p.694)
REIDEL LOBE
- When a Reidel lobe is present; the left lobe of the liver
is respondingly smaller in size.
TRUE OR FALSE.
The left lobe of the liver may; as a normal variant; be elongated and surround a portion of the spleen.(p.694)
TRUE
___ is the most common abnormality demonstrated by hepatic imaging. (p.694)
FATTY LIVER (HEPATIC STEATOSIS)
- 15% prevalent in the general population
- in 50% of patients with hyperlipidemia
- up to 75% of patients with severe obesity
2 most common causes of FATTY LIVER. (p. 694)
- ALCOHOLIC LIVER DISEASE
- NON-ALCOHOLIC FATTY LIVER DISEASE
related to metabolic syndrome of insulin resistance; obesity; diabetes; hyperlipidemia and hypertension.
Give 6 other causes of fatty liver aside from alcoholic liver disease and non-alcoholic fatty liver disease. (p.694)
- VIRAL HEPATITIS
- DRUGS (esp.steroids and chemotherapy agents)
- NUTRITIONAL ABNORMALITIES
- RADIATION INJURY
- CYSTIC FIBROSIS
- all conditions injure hepatocytes by altering hepatocellular lipid metabolism; with defects in free fatty acid metabolism resulting in accumulation of triglycerides within hepatocytes. - STORAGE DISORDERS
Fatty liver is initially reversible but may progress to____ with further progression to cirrhosis. (p.694)
STEATOHEPATITIS
CELL INJURY; INFLAMMATION AND FIBROSIS
____ includes a continuum of liver disease that extends from simple fatty liver through non-alcoholic steatohepatitis (NASH) to cirrhosis. (p.694)
NON-ALCOHOLIC FATTY LIVER DISEASE (NASH)
- is diagnosed solely by liver biopsy showing inflammation and fibrosis in addition to hepatic steatosis.
On US, the normal liver parenchyma is equal to; or slightly more
echogenic; than the ___ and ____ parenchyma. (p.695)
RENAL CORTEX and SPLENIC PARENCHYMA
Three reliable US findings of fatty liver (p.695)
- LIVER ECHOGENICITY distinctly greater than that of the renal cortex
- LOSS OF VISUALIZATION of normal echogenic portal triads in the periphery of the liver.
- POOR SOUND penetration with loss of definition of the diaphragm.
On CT; fat infiltration lowers the attenuation of the hepatic parenchyma; and makes the liver appear ____ dense than the spleen. (p.695)
LESS
- the liver normally has a slightly higher attenuation than the spleen or blood vessels.
- differences in density between liver and spleen are most reliably judged on non-contrast images
- on postcontrast images; the normal spleen enhances maximally 1 to 2 minutes before maximal liver enhancement and is thus transiently brighter than the normal liver.
Fatty liver enhances __ than normal liver. (p.695)
LESS
On unenhanced CT; fatty liver is diagnosed when the liver attenuation is __ H less than the spleen attenuation; or when the liver attenuation is less than ___ H. (p.695)
10 H; 40 H
- when fatty liver is severe; blood vessels may appear brighter than the dark liver on unenhanced CT
Comparison of CT and US findings may yield the diagnostic ________ sign; with fatty liver being dark on CT and bright on US. (p.695)
FLIP-FLOP sign
___ is the MR method most sensitive to the diagnosis of fatty liver. (p.695)
GRADIENT ECHO IMAGING WITH FAT AND WATER MOLECULES IN-PHASE AND OUT-OF-PHASE
- same technique used to characterize benign adrenal adenomas
On IN-PHASE images; the signal from water and fat molecules
are _____. (p.695)
ADDITIVE
ON OUT-PHASE images; the signals from water and fat _____.
p.695
CANCEL OUT EACH OTHER
A loss of signal intensity between in-phase and out-of-phase
images is indicative of ____. (p.695)
FATTY LIVER
This opposed-phase chemical shift GRE technique is more sensitive in the detection of _____ intracellular fat characteristic of fatty liver. (p.695)
MICROSCOPIC intracellular fat
Fat-saturation MR techniques, have greater sensitivity for __fat.
(p.695)
MACROSCOPIC fat
Iron deposition in the liver will also cause a ___ on out-of-phase
MR imaging and is a potential pitfall in MR diagnosis of fatty liver in patients with cirrhosis. (p.695)
LOSS OF SIGNAL
Characteristic features of fatty deposition include these TWO findings. (p.695)
- LACK OF MASS EFFECT (no bulging of the liver contour or displacement of intrahepatic blood vessels)
- ANGULATED GEOMETRIC BOUNDARIES between involved and uninvolved parenchyma.
Fatty changes can develop within __ weeks of hepatocyte insult and may resolve within __ days of removing the insult. (p.695)
3 weeks: 6 days
- patterns of fatty infiltration are strongly related to hepatic blood flow.
____ fatty liver involving the entire liver is the most common pattern. (p.695)
DIFFUSE fatty liver
____ fatty liver involves a geographic or fan-shaped portion of the liver with the same imaging features as diffuse fat deposition.
FOCAL fatty liver
- focal fat may simulate a liver tumor;
- however the area of involvement has a density characteristic of fat.
Focal fat (in fatty liver); is most adjacent to the ___; ____ and ____. (p.695)
FALCIFORM LIGAMENT; GALLBLADDER FOSSA; AND PORTA HEPATIS
- these are the areas prone to altered hepatic blood flow with systemic flow; and focal fat deposition may be related to higher concentrations of insulin in these areas.
______ in a diffusely fatty infiltrated liver may be the most confusing pattern becaused spared areas of normal parenchyma may convincingly simulate a liver tumor. (p.695)
FOCAL SPARING
Fat-spared areas are most commonly found in segment ___.
p.696
segment IV
The fat-spared area is hypoechoic relative to the rest of the liver on US and is of higher density than the rest of the liver on CT.
What is this RADIOLOGIC SIGN? (p.696)
FLIP-FLOP sign
___ fatty liver is an uncommon pattern of fat deposition throughout the liver in multiple atypical locations. (p.696)
MULTIFOCAL FATTY LIVER
____ fatty liver is seen as HALOS OF FAT surrounding the portal veins; hepatic veins or both. (p.696)
PERIVASCULAR fatty liver
- unknown cause
____ fatty liver is seen only in patients with renal failure on peritoneal dialysis and only when INSULIN is added to the dialysate. (p.696)
SUBCAPSULAR fatty liver
- high concentrations of INSULIN in the subcapsular liver leads to fat deposition
\_\_\_\_\_ hepatitis most commonly causes no abnormalities on hepatic imaging (p.696)
ACUTE hepatitis
- in some patients; diffuse edema lowers the parenchymal echogenicity and causes the portal venules to appear unusually bright on US.
In ____ hepatitis; areas of necrosis show ill-defined areas of low density on CT. (p.696)
ACUTE FULMINANT hepatitis
_____ hepatitis is characterized pathologically by portal and perilobular inflammation and fibrosis. (p.696)
CHRONIC hepatitis
- causes include chronic viral infection; and hepatitis B and C.
- perilymphatic lymph nodes are commonly visualized.
- US may show a subtle coarse increase in hepatic echogenicity.
The primary role of imaging patients with chronic hepatitis is to detect ____. (p.696)
HEPATOCELLULAR CARCINOMA
____ is characterized pathologically by diffuse parenchymal destruction fibrosis with alteration of hepatic architecture; and innumerable regenerative nodules that replace normal liver parenchyma. (p.696)
CIRRHOSIS
Give 4 causes of cirrhosis. (p. 696)
- HEPATIC TOXINS
(alcohol; drugs; and aflatoxin from a grain fungus) - INFECTION (viral hepatitis; esp.types B and C)
- BILIARY OBSTRUCTION
- HEREDITARY (Wilson Disease)
In the U.S.: 75% of cirrhotic patients are ___.
In Asia and Africa: most cases of cirrhosis are due to ___.
(p.____)
CHRONIC ALCOHOLICS;
CHRONIC ACTIVE HEPATITIS
7 imaging findings of CIRRHOSIS? (p.696)
- HEPATOMEGALY (early)
- ATROPHY OR HYPERTROPHY of hepatic segments
- COARSENING OF HEPATIC PARENCHYMAL TEXTURE.
- NODULARITY OF THE PARENCHYMA; often most noticeable on the liver surface
- HYPERTROPHY OF THE CAUDATE LOBE with shrinkage
of the right lobe - REGENERATING NODULES
- ENLARGEMENT OF THE HILAR PERIPORTAL SPACE
(>10 mm) reflecting parenchymal atrophy.
Extrahepatic signs of CIRRHOSIS include the presence of
_______ as evidence of portal hypertension; splenomegaly;
and ascites. (p.696-697)
PORTOSYSTEMIC COLLATERALS
TRUE OR FALSE.
The pathological changes of cirrhosis are irreversible; but disease progression can be limited or stopped by eliminating the causative agent. (stop drinking alcohol). (p.____)
TRUE
______ is an effective treatment for portal hypertension and
long-term control of esophageal variceal bleeding. (p.697)
TRANSJUGULAR INTRAHEPATIC PORTOSYSTEMIC SHUNT (TIPS)
DIAGNOSIS?
US finding of heterogeneous parenchymal with coarsening of the echotexture and decreased visualization of the small portal triad structures. (p.697)
CIRRHOSIS
- CT finding may be normal in the early stages or may reveal parenchymal inhomogeneity with patchy areas of increased and decreased attenuation.
- MR shows heterogeneous parenchymal signal on T1WI and T2WI. High-signal fibrosis on T2WI is the predominant cause of the heterogeneous appearance.
_____ are conditions that cause diffuse hepatic nodularity or portal hypertension including pseudocirrhosis of treated breast CA metastases; miliary metastases; sarcoidosis; schistosomiasis; Budd-Chiari syndrome; nodular regenerative hyperplasia and idiopathic portal hypertension. (p.697)
MIMICS OF CIRRHOSIS
HCC may arise ____ or as a _______ process from a regenerative
nodule to low-grade dysplastic nodule to high-grade dysplastic nodule to small HCC to large HCC. (p.697)
DE NOVO or STEPWISE
_____ are the most common nodule and are a regular pathologic feature of cirrhosis due to attempted repair of hepatocyte injury. (p.697)
REGENERATIVE NODULES
- composed primarily of hepatocytes that are surrounded by coarse fibrous septations.
Small regenerative nodules size? (p.___)
< 3 mm
Larger regenerative nodules (> __ mm) produce the macronodular pattern of cirrhosis. (p.697)
> 3 mm
Very large regenerative nodules (up to __ cm) can mimic
mass. (p.697)
up to 5 cm
Regenerative nodules are supplied by the _____ and thus show no enhancement on arterial phase postcontrast imaging. (p.____)
PORTAL VEIN
Regenerative nodules, because they consist of proliferating hepatocytes, are typically _____ on US; CT and MR imaging.
(p.697)
INDISTINCT
- uncommonly; regenerative nodules are hyperintense to liver on T2WI; reflecting the accumulation of fat; protein or copper.
Regenerative nodules that accumulate iron (siderotic nodules) are ___ signal intensity on T1WI and T2WI. (p.697)
LOW
Infarction of regenerative nodules results in __ signal on T2WI.
(p.697)
HIGH
Regenerative nodules show ___ enhancement on arterial phase postcontrast CT and MR imaging. (p.697)
NO
____ nodules show foci of low-grade or high-grade dysplasia.
p.697
DYSPLASTIC
____ -grade dysplastic nodules show minimal atypia;
have no mitosis; and are not premalignant. (p.697)
LOW-grade dysplastic nodules
____ -grade dysplastic nodules shows moderate atypia; have occasional mitosis; may secrete alpha fetoprotein (AFP), but are not frankly malignant. (p.697)
HIGH-grade dysplastic nodules
- they are however considered premalignant
TRUE OR FALSE.
Dysplastic nodules are almost never hyperintense on T2WI,
differentiating them from HCC. (p.697)
TRUE
Siderotic dysplastic nodules with iron accumulation are ___ signal on T1WI and T2WI. (p.698)
LOW
___ nodule is a radiologic term used to describe nodules that are high iron content and appear as low-signal nodules on both T1WI and T2WI. (p.698)
SIDEROTIC nodule
TRUE OR FALSE.
Dysplastic nodules may disappear on imaging follow-up.
(p.698)
TRUE
____ HCC; defined as less than 2 cm diameter; overlap the
appearance of high-grade dysplastic nodules. (p.698)
SMALL HCC
- on T1WI: hypointense nodule with internal foci isointense to liver parenchyma
- on T2WI: the nodules are of low intensity with foci of high-signal intensity.
TRUE OR FALSE.
High signal intensity on T2WI differentiates small HCC from dysplastic nodules. (p.699)
TRUE
___ content within the nodules raises the risk of HCC. (p.699)
FAT
Small HCCs shows the hallmark finding of ____ enhancement
on ____ phase dynamic MR. (p.699)
INTENSE; ARTERIAL
TRUE OR FALSE.
The American Association for the Study of Liver Diseases
(AALSD) no longer requires biopsy to diagnose HCC.
(p.___)
TRUE
Small nodules that are ________ on arterial phase postcontrast
CT or MR and show _____ of contrast on portal venous phase
are considered to be HCC. (p.699)
HYPERVASCULAR: WASHOUT
HCC developing within a dysplastic nodule may produce a characteristic _____ appearance seen as a high-signal focus within a low-intensity nodule. (p.699)
NODULE WITHIN A NODULE
- high signal focus enhances avidly on arterial phase.
On US; ____ HCCs appear as a well-circumscribed hypoechoic mass in the cirrhotic liver. (p.699)
SMALL HCC
- on T1WI: hypointense nodule with internal foci isointense to liver parenchyma
- on T2WI: the nodules are of low intensity with foci of high-signal intensity.
3 MIMICS OF HCC? (p.699)
- NON-SPECIFIC ARTERIALLY ENHANCING LESIONS
- PSEUDOLESIONS
- THADs
- lesions are features of cirrhosis related to arterio-portal shunts and fibrotic obstruction of the portal vein.
- these non-specific lesions are usually isointense on delayed imaging; unlike in HCC which commonly becomes hypointense to the surrounding liver on delayed imaging.
_____ describes mass-like areas of fibrosis found in livers with
advanced cirrhosis. (p.699)
CONFLUENT FIBROSIS
- extensive fibrosis produces a wedge
- shaped mass radiating from the porta hepatis associated with parenchymal atrophy and flattening or retraction of the liver capsule.
Key feature of Confluent Liver Fibrosis. (p.699)
VOLUME LOSS OF THE AFFECTED PORTION OF THE LIVER.
*the central portion of the right hepatic lobe is most often involved.
CT Imaging appearance of Confluent Liver Fibrosis in A. Noncontrast-CT B. Arterial phase contrast CT C. Portal venous phase contrast CT (p.699)
A. NECT: LOW ATTENUATION
B. Arterial phase CECT:
MOST LESIONS (60%) SHOW LITTLE TO NO ENHANCEMENT; WHEREAS THE REMAINDER ISOENHANCE WITH LIVER PARENCHYMA
C. Portal venous phase CECT:
MOST LESIONS ARE HYPODENSE OR ISODENSE TO LIVER PARENCHYMA; whereas 17% showed
hyperenhancement
MR Imaging appearance of Confluent Liver Fibrosis in A. On T1WI B. On T2WI C. Postcontrast MR (p.\_\_\_\_)
A. T1WI: Hypointense
B. T2WI: ACUTE fibrosis
- has high fluid content and appears bright on T2WI
CHRONIC fibrosis
- is low in fluid content and appears bright on T2WI
C. Post-Contrast MR:
Negligible enhancement on arterial phase and late enhancement on delayed venous phase.
_____ is a pathological increase in portal venous pressure that results in the formation of portosystemic collateral vessels that divert blood flow away from the liver into the systemic circulation.
(p.699)
PORTAL HYPERTENSION
3 causes of PORTAL HYPERTENSION (p.699)
- PROGRESSIVE VASCULAR FIBROSIS ASSOCIATED WITH CHRONIC LIVER DISEASE
- PORTAL VEIN THROMBOSIS OR COMPRESSION
- PARASITIC INFECTIONS (SCHISTOSOMIASIS)
9 imaging signs of PORTAL HYPERTENSION (p.699)
- Visualization of portosystemic collaterals
(coronary; gastroesophageal; splenorenal; paraumbilical; hemorrhoidal; and retroperitoneal) - Increased portal vein diameter (>13mm)
- Increased superior mesenteric and splenic vein diameters (>10mm)
- Portal vein thrombosis
- Calcifications in the portal and mesenteric veins
- Edema in the mesentery; omentum and retroperitoneum
- Splenomegaly due to vascular congestion
- Ascites
- Reversal of flow in any portion of the portal venous system (hepatofugal flow)
_______ may occur as a complication of cirrhosis; or may be caused by portal vein invasion or compression by tumor; hypercoagulable states; or inflammation (pancreatitis). (p.699)
PORTAL VEIN THROMBOSIS
On CT and US; the _____ is seen as a hypodense plug within the portal vein. (p.699)
THROMBUS
TRUE OF FALSE.
Malignant thrombus in the portal vein is contiguous with and extends from the primary tumor. (p.699-700)
TRUE
TRUE OF FALSE.
Cavernous transformation of the portal vein develops when small collateral veins adjacent to the portal vein expand and replace the obliterated portal vein. (p.700)
TRUE
- These collateral veins appear as a tangle of small vessels surrounding the thrombosed portal vein
_____ refers to a group of disorders characterized by obstruction to hepatic venous outflow involving one or more hepatic veins. (p.700).
BUDD-CHIARI SYNDROME
TRUE OR FALSE.
Hepatic venous obstruction causes increased pressure in the hepatic sinusoids; resulting in liver congestion; portal hypertension and decreased hepatic perfusion. (p.700)
TRUE
Three causes of Budd-Chiari syndrome (p.700)
- COAGULATION DISORDERS
- MEMBRANOUS WEBS OBSTRUCTING
THE HEPATIC VEINS OR IVC (most common in Asian countries) - MALIGNANT TUMOR INVASION OF THE HEPATIC VEINS
- CAUDATE lobe is spared because of its venous drainage to the IVC.
COMMA SIGN is seen in what syndrome? (Comma-shaped intrahepatic collateral vessels may be seen on CT or MR.
(p.700)
BUDD-CHIARI SYNDROME
In BUDD-CHIARI SYNDROME; blood flow to the right and left hepatic lobes is severely impaired resulting in a characteristic _______ pattern on contrast-enhanced CT. (p.700)
FLIP-FLOP pattern
_______ is a common complication of congestive heart failure and constrictive pericarditis. (p.700)
PASSIVE HEPATIC CONGESTION
- Hepatic venous drainage is impaired and the liver becomes becomes engorged and swollen.
4 Imaging findings in PASSIVE HEPATIC CONGESTION (p.700)
- DISTENTION OF THE HEPATIC VEINS AND IVC
- REFLUX OF IV CONTRAST INTO THE HEPATIC VEINS
AND IVC - INCREASED PULSATILITY OF THE PORTAL VEIN
- INHOMOGENEOUS CONTRAST ENHANCEMENT OF THE LIVER.
4 Secondary findings in PASSIVE HEPATIC CONGESTION
p.700
- Hepatomegaly
- Cardiomegaly
- Pleural effusions
- Ascites
_____ may be primarily resulting from a hereditary disorder that increases dietary iron absorption or secondary due to excessive iron intake usually from multiple blood transfusions or chronic
disease including cirrhosis; myelodysplastic syndrome and certain anemias. (p.700)
HEMOCHROMATOSIS
- the susceptibility effect of iron; best appreciated on T2* images; causes loss of signal in tissues with excessive iron accumulation.
The ____ pattern of iron deposition is seen with increased iron absorption of primary hemochromatosis and with secondary hemochromatosis caused by chronic anemias. (p.700)
PARENCHYMAL
The ____ pattern of iron deposition is seen in secondary hemochromatosis; with iron overload caused by blood transfusions. (p. 700)
RETICULOENDOTHELIAL
- excess iron accumulation occurs in reticuloendothelial
cells in the liver; spleen; and bone marrow - MR shows diffuse decreased signal in all three areas.
The ___ pattern of iron deposition is rare but dramatic;
occuring only in patients with intravascular hemolysis caused by mechanical heart valves. (p.700)
RENAL
- excess iron deposition occurs in the proximal convoluted tubules of the renal cortex; causing a loss of cortical signal. On T1WI and T2WI; and thus reverse in the normal corticomedullary differentiation pattern.
Gas in the _____ may be an ominous imaging sign associated with bowel ischemia in adults and necrotizing enterocolitis in infants. (p.701)
gas in the PORTAL VENOUS SYSTEM
- CT reveals air in branching tubular structures extending to the liver capsule.
- Air is commonly evident within the mesenteric and central portal veins
- conventional radiographs show streaks of low density in the periphery of the liver.
GAS IN THE PORTAL VENOUS SYSTEM versus AIR IN BILIARY TREE? (p.701)
In distinction; AIR IN THE BILIARY TREE is more central;
not extending to within 2 cm from the liver capsule.
In normal liver; the most common hypervascular lesions are ____ (GIVE 4). (p.701)
- HEMANGIOMA;
- FOCAL NODULAR HYPERPLASIA;
- HEPATIC ADENOMA
- HYPERVASCULAR METASTASES
In cirrhosis; the most common hypervascular lesions are __ and ___.
(p.701)
HCC and DYSPLASTIC NODULES
____ are the most common MALIGNANT masses in the liver.
p.701
METASTASES
- 20 times more common than primary liver malignancies
Hepatic metastases most commonly originate from the __; __ and __. GIVE 3. (p.701)
GI TRACT; BREAST and LUNG
MNEMONIC: Liver Mets BLoG
The most characteristic feature of Liver Metastases is ______ enhancement; creating a ______ on post-contrast CT and MR images. (p. 701)
BAND-LIKE PERIPHERAL enhancement;
TARGET LESION
TRUE OR FALSE. Metastatic disease must be considered in the
differential diagnosis of virtually all hepatic masses. (p.701)
TRUE
- multiplicity of lesions favors metastatic disease
On CT; hypovascular metastases are most apparent on _____ phase images when the background liver is maximally enhanced and the metastatic lesions are of low attenuation. (p.701)
PORTAL VENOUS phase
The most common HYPOVASCULAR LIVER METASTASES are___ (GIVE 5). (p.702)
- COLORECTAL
- LUNG
- PROSTATE
- GASTRIC
- UROEPITHELIAL CARCINOMAS
Mnemonic: Check PLUG
TRUE OR FALSE. HYPERvascular metastases overlap the appearance of HCC. (p.702)
TRUE
- MR and CT show arterial phase enhancement with rapid washout on portal venous and delayed images.
HYPERVASCULAR METASTASES are associated with ____
GIVE 6). (p.702
1. PRIMARY NEUROENDOCRINE TUMORS (pancreatic islet tumors; carcinoid tumor;and pheochromocytoma). 2. RENAL CELL CARCINOMA 3. THYROID CARCINOMA 4. MELANOMA 5. SOME SARCOMAS 6. CHORIOCARCINOMA
_____ is second only to metastases as the common cause of a liver mass. (p.702)
CAVERNOUS HEMANGIOMA
What is the most common benign liver neoplasm?;
found in 7% to 20% of the population and more commonly in women.(p.702)
CAVERNOUS HEMANGIOMA
- this tumor consists of large; thin-walled; blood-filled vascular spaces separated by fibrous septa.
- blood flow through the maze of vascular spaces is extremely slow; resulting in characteristic imaging findings.
- thrombosis within the vascular channels may result in central fibrosis and calcification
Larger lesions; GIANT HEMANGIOMAS (> ____ cm); occasionally causes symptoms. (p.702)
> 5 cm
TRUE OR FALSE. The size of most cavernous hemangiomas is stable over time. (p.702)
TRUE
- enlargement of cavernous hemangiomas is a cause for reassessment.
US feature of a cavernous hemangioma. (p. 702)
Well-defined; uniformly hyperechoic mass in 80% of patients
- no Doppler signal is obtained from most cavernous hemangiomas because the flow is too slow.
CT feature of a cavernous hemangioma. (P. 702)
Well-defined; hypodense mass on unenhanced scans
- because the lesion consists mostly of blood;attenuation of the hemangioma is similar to that of blood vessels within the liver.
What is the characteristic pattern of enhancement with bolus IV contrast in cavernous hemangiomas? (p.702)
DISCONTINUOUS NODULAR ENHANCEMENT FROM THE PERIPHERY OF THE LESION THAT GRADUALLY BECOMES ISODENSE OR HYPERDENSE COMPARED TO THE LIVER PARENCHYMA.
- the degree of contrast enhancement parallels that of hepatic blood vessels during all postcontrast phases.
The contrast enhancement in cavernous hemangiomas persists
for __ to __ minutes following injection because of slow flow within the lesion. (p. 702)
20 to 30 minutes
Areas of fibrosis remain ____ in all image sequences. (p. 702)
DARK
MR contrast enhancement pattern of cavernous hemangiomas.
p.702
Well-marginated mass with discontinuous peripheral nodular enhancement; leading to progressive fill-in of the lesion
on delayed imaging (>5 minutes).
- brightness of enhancement parallels the blood pool
Central areas of fibrosis,usually seen in ___ hemangiomas (>5 cm); do not enhance. (p.702)
GIANT
_____ hemangiomas (< 1.5 cm) fill in more rapidly; and the peripheral nodular enhancement may not be evident depending upon the timing of the images. (p.703)
SMALL CAPILLARY hemangiomas
FLASH hemangiomas ____ contrast on delayed images;
whereas other small early phase-enhancing lesions; such as
HCC and hypervascular metastases; show early and progressive
_____. (p.703)
RETAIN; CONTRAST-WASHOUT
Radionuclide scanning using _____ as a blood pool agent is extremely accurate in the diagnosis of cavernous hemangioma. (p. 703)
TECHNETIUM-LABELED RED BLOOD CELLS
____ is the most common primary malignancy of the liver.
p.703
HEPATOCELLULAR CARCINOMA
- 5th most common tumor in the world and the 3rd most common cause of cancer-related death (following lung and gastric cancer).
Give 3 risk factors of HEPATOCELLULAR CARCINOMA. (p.703)
- CIRRHOSIS
- CHRONIC HEPATITIS
- VARIETY OF CARCINOGENS
(sex hormones; aflatoxin; and thorotrast)
Mnemonic: 3 C’s of HCC
In asia; most HCCs are found in patients with _____. (p.703)
CHRONIC ACTIVE VIRAL HEPATITIS
___ is the most sensitive imaging modality for the detection of HCC at 81% (p.703)
MR
Elevation in serum ______ is found in 90% of patients and is strongly suggestive of hepatoma in patients with cirrhosis.
(p.703)
ALPHA FETOPROTEIN
Three major growth patterns of hepatomas that affect their imaging appearance. (p.703-704)
- SOLITARY MASSIVE
- MULTINODULAR
- DIFFUSE INFILTRATIVE
_____ HCC growth pattern which appears as a single large mass with or without satellite nodules. (p.704)
SOLITARY MASSIVE HCC
____ HCC growth pattern which appears as multiple discrete nodules involving a large area of the liver. (p.704)
MULTINODULAR HCC
_____ HCC growth pattern which manifests as innumerable tiny indistinct nodules throughout the liver distorting the parenchyma but not causing a discrete mass. (p.704)
DIFFUSE HCC
High intensity on T1WI reflects the accumulation of __; ___ or ____ within the tumor (HCC). (p.704)
FAT; GLYCOGEN; or COPPER
- fat shows signal loss on opposed-phase or fat saturation images.
Moderate high signal on T2WI is quite specific for HCC as dysplastic nodules are not high signal unless ____. (p.704)
INFARCTED
Arterial phase enhancement in HCC reflects ____ with supply from the ____ artery. (p.704)
- This is considered an essential characteristic for diagnosis.
NEOANGIOGENESIS; HEPATIC artery
- enhancement is HOMOGENOUS in small lesions and HETEROGENOUS in large lesions.
The classic and most common appearance of HCC on MR is
___ signal on T1WI; __ signal on T2WI; with ____ enhancement and venous _____. (p.704)
LOW; HIGH; ARTERIAL ENHANCEMENT;VENOUS WASHOUT
- delayed images commonly show late enhancement of an outer rim or capsule; a feature highly sensitive and specific.
6 imaging characteristics of large HCCs (p.704)
- MOSAIC PATTERN (80 to 90% with HCC)
of confluent small nodules separated by thin septations and necrotic areas; best seen on T2WI - DISTINCT TUMOR CAPSULE
- EXTRACAPSULAR EXTENSION (40% to 80%)
of tumor with satellite lesions or tumor projection through the capsule - VASCULAR INVASION (25%) of tumor into portal veins or; less commonly hepatic veins
- EXTRAHEPATIC DISSEMINATION to abdominal lymph nodes; bones; lungs; and adrenals
- PATTERN OF CONTRAST ENHANCEMENT
- heterogeneous enhancement during arterial phase with rapid washout of contrast during portal venous and equilibrium phase.
Washout to become hypointense on delayed postcontrast images is a feature of ____; not seen with regenerative or dysplastic nodules. (p.705)
HCC
_______ is a common finding related to portal vein compression
or occlusion by the tumor with compensatory increase in hepatic arterial supply. (p.____)
PERITUMORAL ARTERIAL PHASE ENHANCEMENT
- peritumoral enhancement is commonly wedge-shaped and confined to the segment of the liver with compromised portal venous supply. (p.705)
Approximately 24% of liver tumors are surrounded by a fibrous capsule or pseudocapsule. This encapsulated HCC; a variant of the solitary massive form; is found more frequently seen in ____ populations and has a ___ prognosis.(p.____)
ASIAN; BETTER
___ metamorphosis is a common histologic finding in HCC and hepatic adenomas.(p.705)
FATTY metamorphosis
_____ shunting is seen as early or prolonged enhancement of the portal vein; or as a wedge-shaped area of parenchymal enhancement adjacent to the tumor.(p.705)
ARTERIOPORTAL shunting
Abundant copper binding protein in cancer cells may lead to _____ within the tumor. (p.705)
EXCESSIVE COPPER ACCUMULATION
- high copper concentration causes the tumor to appear hyperdense on noncontrast CT and hyperintense (due to T1 shortening effect) on T1WI on MR.
____ HCC (approximately 13% of cases) appears as a heterogeneous permeative extensive tumor difficult to differentiate from the distorted parenchyma or cirrhosis.
DIFFUSE HCC
- Vascular invasion and portal vein thrombosis is a prominent clue to the diagnosis.
- hypointensity on delayed images is highly indicative of diffuse tumor.
______ is as benign solid mass consisting of abnormally arranged hepatocytes, bile ducts and Kupffer cells. (p.705)
- second to hemangioma as the most common benign liver tumor
FOCAL NODULAR HYPERPLASIA (FNH)
- most tumors are diagnosed in women of childbearing age.
Liver lesion that is mostly solitary; less than 5 cm in diameter;
and are hypervascular with a CENTRAL FIBROUS SCAR containing thick-walled blood vessels.
- Lesions are lobulated and well-circumscribed but lack a capsule.
(p.705)
FOCAL NODULAR HYPERPLASIA (FNH)
- benign lesions that do not require treatment but must be differentiated from hepatic adenoma and fibrolamellar carcinoma.
- found most commonly in women
- twice as common as hepatic adenoma and is not related to oral contraceptive use
Because of the presence of ___ cells, most (50% to 70%) FNH will show normal or increased radionuclide activity on technetium sulfur colloid liver-spleen scans. (p. 705)
KUPFFER CELLS
DIAGNOSIS?
US finding of slight bulge in the liver contour or subtle alteration of parenchymal echogenicity may be the only clues to the presence
of a lesion. Color Doppler may show its central vascularity.
(p.705)
FOCAL NODULAR HYPERPLASIA(FNH)
DIAGNOSIS?
CT FINDING of a subtle; slightly hypoattenuating lesion on unenhanced images.
Post-contrast shows characteristic intense homogeneous enhancement in arterial phase sometimes with visualization of the large feeding vessels.
Contrast washes out early on portal venous phase.
The lesion is isointense and commonly near invisible on delayed-phase equilibrium images. (p.705)
FOCAL NODULAR HYPERPLASIA (FNH)
MR key diagnosis to recognize Focal Nodular Hyperplasia?
p.705
FNH is near isointense to liver parenchyma on all precontrast MR sequences
- central scar is hypointense on T1WI and isointense to slightly hyperintense on T2WI
______ are rare; benign liver tumor that carry a risk of life threatening hemorrhage and potential for malignant degeneration.(p.705)
HEPATIC ADENOMAS
- surgical removal of the tumor is advocated