Transcript Liver masses detection & characterization

Detection of liver masses
* arterial phase imaging
* portal venous phase
* equilibrium phase
Characterization of liver masses
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Hypervascular lesions
Hypovascular lesions
Scar
Capsule
Calcification
Fat
Hemorrhage
Cystic components
Retraction of liver capsule
Peripheral enhancement & progressive fill in
• Minority of tumors contain calcifications , cystic
components, fat or hemorrhage and will be detected on
NECT.
• When we give IV contrast, it is important to understand
that there is a dual blood supply to the liver.
• Normal parenchyma is supplied for 80% by PV & only for
20% by hepatic artery, so it will enhance in the portal
venous phase.
• All liver tumors however get 100% of their blood supply
from hepatic artery , so when they enhance it will be in
arterial phase
• Small HCC in
cirrhotic liver
, not visible
on NECT ,
clearly visible
in arterial
phase, and
not visible in
portal venous
phase.
• In the arterial phase hypervascular tumors will
enhance via the hepatic artery , when normal
liver parenchyma does not yet enhances ,
because contrast is not yet in the portal venous
system.
• These hypervascular tumors will be visible as
hyperdense lesions in a relatively hypodense
liver
• However when the surrounding liver
parenchyma starts to enhance in the portal
venous phase , these hypervascular lesions may
become obscured.
• In the portal venous phase hypovascular
tumors are detected when the normal liver
parenchyma enhances maximally.
• These hypovascular tumors will be visible
as hypodense lesions in a relatively
hyperdense liver.
• In the equilibrium phase at about 10
minutes after contrast injection , tumors
become visible, that either loose their
contrast slower than the normal liver , or
wash out their contrast faster than normal
liver parenchyma. These lesions will
become either relatively hyperdense or
hypodense to the normal liver
• Above: arterial
phase showing
hypervascular FNH
• Middle: portal
venous phase
showing
hypovascular
metastases
• Down: equilibrium
phase showing
relatively dense
cholangiocarcinoma
Arterial phase imaging
• Optimal timing and speed of contrast
injection and type of CT scanner are very
important for good arterial phase imaging.
Optimal timing
• Hypervascular tumors will enhance
optimally at 35 seconds after contrast
injection (late arterial phase)
• A patient who underwent
two phases of arterial
imaging at 18 and 35
seconds .
• In the early arterial phase
we nicely see the arteries
, but we only see some
irregular enhancement
within the liver .
• In the late arterial phase,
we can clearly identify
multiple tumor masses.
• Notice that in the late arterial phase, there
has to be some enhancement of the portal
vein .
• The only time that an arterial phase is
needed is when you need an arteriogram ,
for instance as a roadmap for
chemoembolization of a liver tumor.
Speed of contrast injection
For arterial phase the best results are with
an injection of 5 ml/sec
• Patient with liver
cirrhosis and
multifocal HCC
injected at 2.5
ml/sec and at 5
ml/sec.
• At 5 ml/sec. there
is far better
contrast
enhancement and
better tumor
detection.
Type of CT scanner
• If you have a single slice scanner , it will take
about 20 seconds to scan the liver.
• For late arterial phase imaging 35 sec. is the
optimal time , so you start at about 25 seconds
and end at about 45 seconds.
• However if you have 64 multislice scanner , you
will be able to examine the whole liver in 4
seconds , so you start scanning at about 33
seconds.
Tripple Phase Helical CT
Axial C+ CT
Portal Venous
Phase
Axial C+ CT
Arterial Phase
Axial C+ CT
Hepatic Venous
Phase
Contrast Injection
Arterial
0
15
30
Portal Venous
Time (sec)
Hepatic Venous
45
60
Foley, WD. Multiphase Hepatic CT with a Multirow Detector CT Scanner. 2000 (175): 679-685.
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Portal venous phase
• Portal venous phase imaging work on the opposite idea .
We image the liver when it is loaded with contrast
through the portal vein to detect hypovascular tumors.
• The best moment to start scanning is at about 75 sec.,so
this is a late portal phase , because enhancement of
portal vein already starts at 35 sec in the late arterial
phase.
• Late portal venous phase is also known as hepatic
phase because there already must be enhancement of
hepatic veins . If you don’t see enhancement of hepatic
veins , you are too early.
• Hypovascular
metastases
seen as
hypodense
lesions in late
portal venous
phase
Liver metastases cancer colon
Equilibrium phase
• Starts when contrast is moving away from
the liver and the liver starts to decrease in
density .
• This phase begins at about 3-4 minutes
after contrast injection and imaging is best
done at 10 minutes after contrast injection.
• This phase can be valuable if you are looking
for:
1- fast tumor washout in hypervascular tumors
2- retention of contrast in blood pool like in
hemangioma
3- retention of contrast in fibrous tissue in capsule
( HCC )or scar tissue ( cholangiocarcinoma or
FNH )
• 1- fast tumor washout
in hypervascular
tumors like HCC
• 2- retention of
contrast in the blood
pool as in
hemangioma
• 3- retention of
contrast in fibrous
tissue in capsule (
HCC ) or scar tissue
(cholangiocarcinoma
, FNH)
Relative hyperdense lesions in
the delayed phase
• Fibrous tissue that’s well organized and dense is very
slow to let iodine or gadolinium in.
• Once contrast gets in however, it is equally slow to get
back out in the equilibrium phase.
• So when the normal liver parenchyma washes out, the
fibrous component of the tumor will look brighter than the
background liver tissue.
• Small
cholangiocarcinoma
not visible in portal
venous phase , but
seen as relative
hyperdense lesion
in the equilibrium
phase.
Relative hypodense lesions in
delayed phase
• In the delayed phase, malignant tumors ( like HCC ) , the
tumor is washed out more than the surrounding liver
parenchyma .
• But benign tumors typically will not show this kind of
wash out , but will stay isodense with liver parenchyma
or some times more dense, in the equilibrium phase.
• These benign lesions don’t have enough neoplastic
neovascularity to have a fast wash out.
• HCC in a
cirrhotic
liver. Notice
fast wash
out in
equilibrium
phase
compared to
surrounding
liver
parenchyma
.
Blood pool and hemangioma
• Normally when we look at lesions filling
with contrast, the density of these lesions
is always compared to the density of the
liver parenchyma.
• In hemangiomas, however you should not
compare the density of the lesion to the
liver but to the bloodpool
• This means that the areas of enhancement in a
hemangioma should match the attenuation of the
appropriate vessels { bloodpool } at all times.
• So, in the arterial phase the enhancing parts of
the lesion must have almost the same attenuation
value as the enhancing aorta.
• While in the portal phase, it must match the
attenuation value of the portal vein . And so in
venous or delayed phase.
• So, if it does not match the bloodpool in
every single phase of contrast
enhancement FOREGET the diagnosis
of a hemangioma.
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Hemangioma
in nonenhanced
CT, late
arterial, late
portal
venous, and
equilibrium
phase.
Notice that
the
attenuation
of the
hemangioma
matches the
bloodpool in
every single
phase.
• Flash filling
hemangioma
in
unenhanced,
arterial &
portal venous
phase .
Notice it
matches the
bloodpool.
Incidental hyper vascular lesions
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Hemangioma
Focal nodular hyperplasia ( FNH )
Adenoma
Hepatocellular carcinoma ( HCC )
Fibrolamellar hepatocellular carcinoma
Hypervascular mtastases
• It is important to differentiate between “touch”
and “don’t touch” lesions.
• Benign “don’t touch” hypervascular tumors
include hemangioma, FNH, small adenoma.
• “touch lesions” iclude large adenoma ( more
than 5 cm ) and malignant tumors like HCC ,
fibrolamellar HCC and metastases.
Benign hypervascular
lesions
Hemangioma
Hemangioma
• Bloodpool and hemangioma
• Normally when we look at lesions filling with
contrast, the density of these lesions is always
compared to the density of the liver parenchyma.
• In hemangiomas, however you should not
compare the density of the lesion to the liver but
to the bloodpool
• This means that the areas of enhancement in a
hemangioma should match the attenuation of the
appropriate vessels { bloodpool } at all times.
• So, in the arterial phase the enhancing parts of
the lesion must have almost the same attenuation
value as the enhancing aorta.
• While in the portal phase, it must match the
attenuation value of the portal vein . And so in
venous or delayed phase.
• So, if it does not match the bloodpool in
every single phase of contrast
enhancement , foreget the diagnosis of a
hemangioma.
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Hemangioma
in nonenhanced
CT, late
arterial, late
portal
venous, and
equilibrium
phase.
Notice that
the
attenuation
of the
hemangioma
matches the
bloodpool in
every single
phase.
• Hemangiomas less than 1 cm frequently
demonstrate immediate homogenous
enhancement , isodense to aorta.
• Hemangiomas larger than 1 cm generally
show slow centripetal spread of nodular
enhancement
• Flash filling
hemangioma
in
unenhanced,
arterial &
portal venous
phase .
Notice it
matches the
bloodpool.
• Giant
hemangioma
with scar tissue.
Notice that the
enhancement
matches the
bloodpool in all
phases, central
scar is
hypodense on
NECT & stays
hypodense.
Progressive fill in •
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The lesion definitely has some
features of hemangioma like
nodular enhancement in the
arterial phase & progressive fill
in portal venous & equilibrium
phase.
In portal venous phase
however the enhancement is
not as bright as the
enhancement of portal vein .
The conclusion must be that
this lesion doesn’t match blood
pool in all phases , so it can’t
be hemangioma.
So progressive fill in is a nonspecific feature of that can be
seen in many other tumors like
metastases or
cholangiocarcinoma.
The delayed enhancement in
this lesion is due to fibrotic
tissue in a cholangiocarcinoma
& is a specific feature of this
tumor
Rim enhancement
• The enhancement of a
hemangioma starts
peripheral. It is nodular or
globular & discontinuous.
• Rim enhancement is
continuous peripheral
enhancement is never
hemangioma.
• Rim enhancement is a
feature of malignant lesions
, especially metastases.
• Left: rim enhancement in
breast carcinoma
• Right: nodular discontinuous
enhancement in
hemangioma
Atypical hemangioma
Hemangioma on US
• Hemangioma on dynamic MRI will show
the same enhancement characteristics as
on contrast enhanced CT
Focal nodular hyperplasia
FNH
• Non-neoplastic, hyperplastic response to a congenital vascular
malformation.
• At late arterial phase, FNH typically presents with bright
homogenous enhancement , but less intense than the aorta with a
hypodense central scar.
• Smaller (<3cm) FNH , often lack a central scar.
• At portal phase, FNH is often isoattenuating to the normal liver and
may be difficult to delineate.
• Delayed phase often shows hyperattenuation of central scar due to
late opacification of fibrous components ( or due to the AVM scar )
• No calcification, inhomogenity or capsule should be seen in FNH
• Best diagnostic clue: brightly and homogeneously enhancing mass in
arterial phase on CT or MRI with delayed enhancement of the central
scar.
• Central scar containing AVM
• Central scar seen in 2/3 of large and 1/3 of smal FNH.
• No malignant transformation
• No association with oral contraceptives.
• Nuclear study: normal or increase uptake {only FNH contains kuffer
cells that cause increase uptake in 9% of cases }…….pathognomonic
• Classic FNH looks like a cross section of an orange ( central scar,
radiating septa )
Hemangioma & FNH
• FNH seen as
hypervascular
lesion in the
late arterial
phase &
isodense in
the portal
venous phase
. No scar was
seen.
• T2W, T1W
without
gadolinium
and a
delayed
phase after
gadolinium.
Adenoma
• Best diagnostic clue: spherical well defined
hypervascular and heterogenous mass due to fat &
hemorrhage .
• Symptomatic in 80%-abdominal pain- ( FNH
asymptomatic in 80%)
• 98% in yoyung females taking oral contraceptives
• Not seen in males unless on anabolic steroids or
with glycogen storage disease.
• Adenoma
showing
capsule in
delayed
phase
• Female with
acute abdominal
pain
• On portal phase,
hypodense
hepatic lesion
with hemorrhage
adjacent to it,
extending
subcapsularly.
• Fat in
adenom
a
• Hemorrhage
in adenoma
Malignant hypervascular
lesions
Hepatocellular carcinoma
HCC
• Any hypervascular lesion in a cirrhotic liver
is hepatocellular carcinoma untill proven
otherwise.
• HCC may be solitary, multifocal or diffusely
infiltrating.
• Large HCC typically have a mosaic appearance
due to hemorrhage & fibrosis.
• HCC is a silent tumor, so if patients don’t have
cirrhosis or hepatitis C , you will discover them in
a late stage.
• They tend to be large with mozaic pattern , a
capsule , hemorrhage and necrosis.
• HCC become isodense or hypodense to liver in
the portal venous phase due to fast wash-out
• On delayed images, the capsule and sometimes
septa demonstrate prolonged enhancement.
• Large
HCC with
mozaic
pattern in
a non
cirrhotic
liver
• Cirrhotic liver with
hypervascular ,
inhomogenous
lesion.
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inhomogenous
enhancement and
partial capsule are
helpful for the
diagnosis of HCC
• Small HCC in cirrhotic
liver not visible on
NECT , clearly visible
on arterial phase, and
not visible in portal
venous phase
• HCC in
cirrhotic
liver , notice
fast wash
out in
equilibrium
phase
compared
to
surrounding
liver
parenchyma
PS: Triple Phase CT
Axial C- CT
Film Findings:  Nodular liver
 No discrete lesions
Axial C+ CT: Arterial Phase
 Early hyperenhancing lesion
PS: Triple Phase CT
Axial C+ CT: Portal Venous Phase
Film Findings:
 Quick washout of
enhancing lesion
Axial C+ CT: Delayed Phase
 Hypoenhancing lesion with
peripheral rim of enhancement
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• In the arterial phase we see two hypervascular lesions. Now do not
just concentrate on the images, where you see the lesions best. You
have to look at all the other images, because they give you the clue
to the diagnosis.
The upper images show a lesion that is isodens to the liver on the
NECT. In the arterial phase there is enhancement, but not as
dense as the bloodpool. In the portal venous phase the lesion is
again isodense to the surrounding liver parenchyma and you can't
see it. If you only had the portal venous phase you surely would
miss this lesion.
The lower images show a lesion that is visible on all images. You
see it on the NECT and you could say it is hypodens compared to
the liver. Does this help you? No, not in the least. However if you
look at the bloodpool, you will notice that on all phases it is as dense
as the bloodpool.
So we have a HCC in the right lobe on the upper images and a
hemangioma in the left lobe on the lower images. The key is to look
at all the phases.
HCC & PV thrombosis
Many patients with cirrhosis have portal venous
thrombosis and many patients with HCC have
thrombosis.
These are two common findings and they can be
coincidental.
It is very important to make the distinction between just
thrombus and tumor thrombus.
First, if you have a malignant thrombus in the portal vein,
it will always enhance and you'll see it best in arterial
phase.
Secondly, if you have a malignant thrombus in the portal
vein, it will increase the diameter of the vessel.
Sometimes a tumor thrombus may present with
neovascularity within the thrombus .
• Above : diffusely
enhancing tumor
thrombus in HCC
with portal venous
thrombosis.
• Down: tumor
thrombus with
vessels within the
thrombus
Fibrolamellar HCC
• Large hpervascular , heterogenously
enhancing,lobulated mass in a normal, noncirrhotic liver in young adult
• Central fibrotic scar in 60%
• Calcification in 70% of cases
• Normal alpha fetoprotein (increased in HCC)
• Non
enhanced
image , a
fibrolamaellar
HCC usually
presents as a
big mass with
central
calcification.
• FLC in late
arterial phase
, central
calcification &
heterogenous
enhancement
.
• Delayed
phase with
hypodense
central scar
Hypervascular
metastases
Characteritics of hypervascular
metastases
-a hyper vascular 1ry tumor like renal cell
carcinoma, endocrine tumors( thyroid-islet cell –
carcinoid) & some breast carcinoma
-often co-existing hypo and hypervascular
metastases.
-larger lesions are often inhomogenous due to
central necrosis.
Hypervascular metastasis
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Renal cell carcinoma
Islet cell tumors of pancreas
Thyroid carcinoma
Carcinoid
Malignant melanoma
Choriocarcinoma
Pheochromocytoma
15 % of cancer breast
• Hypervascular
metastases
with typical
peripheral
enhancement
• Peripheral
enhancement
in metastases
from breast
carcinoma
Hypervascular metastases
Hypervascular metastases
breast
cancer
Characterization of liver
masses
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Scar
Calcification
Capsule
Fat
Blood
Retraction of liver capsule
Scar
• Focal nodular hyperplasia …… AVM
• Fibrolamellar HCC ……………Fibrous
tissue
• Cavernous hemangioma …….. Fluid
• HCC
• cholangiocarcinoma
Focal nodular hyperplasia
Fibrolamellar HCC
Hemangioma
Calcification
• Metastases
• Fibrolamellar HCC
• Cholangiocarcinoma
• hemangioma
Calcified mestastases ca ovary
Calcified metastases
Fibrolamellar HCC
Capsule
• Hepatocellular carcinoma “ HCC “
• Adenoma
• Biliary cystadenoma
HCC
Adenoma
Fat
• Adenoma
• HCC
• Metastatic liposarcoma
• Angiomyolipoma
Adenoma
Blood
• HCC
• Adenoma
HCC
Adenoma
Retraction of liver capsule
• Cholangiocarcinoma
• Breast cancer metastases
Cholangiocarcinoma
Cancer breast metastases
Hepatic Cyst
Axial C+ CT
Film Findings:
 Sharply demarcated,
non enhancing, water-dense
cyst.
http://bb.westernu.edu/web/Pathology/webpath60/webpath/radi
ol/heparad/
Focal Nodular Hyperplasia
Axial C+ CT
Film Findings:
 Enhancing lesion with
central filling defect (central
scar)
http://uuhsc.utah.edu/rad/medstud/BodyCaseStudies/BodyCa
se6a.htm
Hepatocellular Adenoma
Axial C+ CT
Film Findings:
 Multiple hypoenhancing
heterogenous lesions
Enhancing hepatic veins
UpToDate: Hepatic Adenoma
HCC: MR Imaging
Axial T1 Weighted MR
Precontrast
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Axial T1 Weighted MR
Arterial Phase
Axial T1 Weighted
MR Portal-phase
Variable intensity on T1 and T2 weighted imaging
Early arterial phase enhancement
Quick washout
Rim enhancement of fibrous capsule in
portal/delayed phases
Liver Metastasis (Colonic
Adenocarcinoma)
Axial C+ CT
Film Findings:
 Multiple hypoenhancing
heterogenous lesions
http://www.mypacs.net/repos/mpv3_repo/viz/full/11724/586248.j
pg
Liver Abscess
Axial C+ CT
Film Findings:
 Well demaracated
hypoenhancing lesion
 Rim of increased
enhancement relative to
central region
http://www.e-radiography.net/ibase5/Hepatic/index.htm
• A Walk Through The Differential
Diagnoses:
Lesions
Classical CT Findings
Hepatic Cyst
Sharply demarcated wall, water density,
non-enhancing
Hemangioma
Peripheral filling in of contrast over time
“Light Bulb Sign” on T2 MRI
Focal Nodular
Hyperplasia (FNH)
Early filling in arterial phase with central
filling defect (scar)
Hepatocellular
Adenoma
Metastasis
Variable, central changes due to
hemorrhage often seen
Abscess
Hepatocellular
Carcinoma (HCC)
Mostly multiple low attenuation lesions, rim
enhancement without “filling in”
Well demarcated hypodense areas with
peripheral enhancement, may see gas
Early arterial enhancement, fast washout,
delayed fibrous capsule enhancement
PS
References
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Clinical Radiology Research Unit and Medical Physics Department, St
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British Journal of Radiology (2003) 76, 866-874
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Small hypoattenuating hepatic lesions at Contrast-enhanced CT: Prognostic
importance in patients with breast cancer.
George A. Krakora, MD et al
Radiology 2004; 233:667-673
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by Karhunen PJ.
J Clin Pathol. 1986 Feb;39(2):183-8.
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Atlas of tumor pathology, AFIP, Washington DC, 1988.
by Robert L. Craig
Fibrolamellar Hepatocellular Carcinoma: Imaging and Pathologic Findings in
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Tomoaki Ichikawa, MD, Michael P. Federle, MD, Luigi Grazioli, MD, Juan
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