This document summarizes common focal liver lesions that can be seen on multiphasic CT scans. It describes key features of benign lesions such as hemangioma and focal nodular hyperplasia as well as malignant lesions including hepatocellular carcinoma, cholangiocarcinoma, and metastases. Characteristics of each lesion like appearance on different phases of CT and other modalities like MRI are discussed. Differential features between lesions are also provided to aid in diagnosis.

1. FOCAL LIVER LESIONS
PRESENTED BY
DR.SANTOSH ATREYA
RESIDENT, PHASE –B
RADIOLOGY & IMAGING
BSMMU

2. Focal liver lesions
Benign
 Hemangioma
 Focal nodular
hyperplasia(FNH)
 Adenoma
 Cyst
 Abscess
Malignant
 Hepatocellular
carcinoma(HCC)
 Fibrolamellar
carcinoma(FLC)
 Intrahepatic
cholangiocarcinoma(ICCA)
 Metastases
 Hepatoblastoma
 Lymphoma
 Angiosarcoma
 Epithelial
hemangioendothelioma

4. MULTIPHASIC CT SCAN
For detection, characterization & differentiation
of benign and malignant liver lesions.
Non contrast CT- Calcification, fat,
hemorrhage.
 Contrast CT-
Arterial phase
Portal venous phase
Delayed phase

5. Understanding the phases
Liver has dual blood supply.
Normal parenchyma is supplied for 80% by
portal vein & only for 20% by hepatic artery.
All liver tumors get their blood supply from
hepatic artery.

6. Arterial phase
 20-40sec
 Hypervascular tumors
enhance via the hepatic
artery, when normal liver
parenchyma does not yet
enhance, because contrast
is not yet in the portal
venous system.
 Hypervascular tumors
enhance optimally at 35
sec after contrast injection.
Hypervascular lesions
• Benign:
 Hemangioma
 Adenoma
 FNH
• Malignant:
 HCC
 Metastases(RCC,carcinoi
d,thyroid
ca,NET,sarcoma)

8. Portal venous phase
 Normal liver parenchyma enhances in this phase.
 To detect hypovascular tumors(more common, majorities are
metastases).
 Scanning is done at about 75 seconds.
Delayed/equilibrium/washout phase
 Begins at about 3-4minutes after contrast injection &imaging
is best done at 10 minutes.
 Valuable for washout of contrast (HCC), retention of contrast
in blood pool (hemangioma) & retention of contrast in fibrous
tissue (capsule of HCC, central scar of FNH).

10. HEMANGIOMA
• Commonest benign hyper vascular liver tumor.
• Is composed of multiple vascular channels
lined by endothelial cells.
• Usually asymptomatic & frequently diagnosed
as an incidental finding on imaging.
• More common In female.
• Size varies from a few mm to more than 10 cm
(giant hemangioma).
• Calcification is rare & seen in <10%, usually in
the central scar of giant hemangioma.

11. USG
• Typically well defined, homogeneous & hyper-
echoic lesions(67%-79%).
• May be hypoechoic, within background of
fatty liver.
• Post acoustic enhancement.
• Large lesion-heterogeneous with central hypo
-echoic foci.

13. CT SCAN
• NECT: Well defined low density mass.
• CECT: Diagnostic triad
 Discontinuous, nodular, peripheral enhancement
starting at arterial phase & gradual central filling in.
 Retention of contrast in delayed phase.
 Enhancement must match blood pool in each
phase(similar to aorta in arterial phase , portal vein
in portal venous phase).

16. MRI
• T1WI: Hypo-intense relative to liver
parenchyma.
• T2WI: Significantly hyperintense –producing
light bulb appearance.
• T1C+(GD): Similar to CECT.

18. FOCAL NODULAR HYPERPLASIA
• 2nd most common benign tumor of liver.
• Characterized by a central fibrous scar
surrounded by nodules of hyperplasic
hepatocytes & small bile ductules.
• More prevalent in women of reproductive age
& associated with OCP use.
• Usually solitary(95%).
• No capsule.
• Asymptomatic.

19. USG
 Subtle iso-echoic mass with contour abnormality.
Displacement of vascular structure.
Central scar- hypo-echoic linear or stellate
area, may be hyper-echoic.
Doppler study: well developed peripheral &
central blood vessels are seen.

21. CT SCAN
• NECT: Homogeneous low density mass, often
with a central low density (central scar).
• CECT: lesion enhance markedly & uniformly in
arterial phase with exception of central scar.
• Isodense to normal liver parenchyma in PVP.
• Contrast accumulates within the central scar
in delayed phase.

24. MRI
• T1WI: Iso-intense to normal liver
parenchyma.
• T2WI: Iso to slightly hyper-intense.
• Central scar is hypointense inT1WI &
hyperintense in T2WI.
• T1C+(GD): Similar to CECT.

26. HEPATIC ADENOMA
• Consists of hepatocytes arranged in cords.
• Lacks of portal tracts, hepatic vein, kupffer cell &
biliary canaliculi. Fat & glycogen rich hepatocytes
are often present.
• Most common in women, with H/O OCP or
anabolic steroid.
• Usually solitary.
• Central hemorrhage/necrosis.
• Thin capsule.
• Association: type 1 glycogen storage disease.
• Complication: potential for rupture & may result
hemoperitonium , risk of malignant
transformation.

27. USG
• Nonspecific
• The echogenecity may be iso, hypo , hyperechoic
or mixed.
CT SCAN:
NECT: low attenuation mass (fat, glycogen), high
density if hemorrhage present.
CECT: early peripheral with centripetal
enhancement, no retention of contrast in
later phases because of AV shunting .

30. MRI
• T1WI: mildly increased signal intensity( fat &
hemorrhage).
• T2WI: heterogeneous with iso, hypo &
hyperintense areas.
• Capsule-hypointense rim.
• T1C+(GD) : similar to CECT.

32. HEPATOCELLULAR CARCINOMA(HCC)
Commonest primary malignant neoplasm of liver.
Consists of abnormal hepatocytes arranged in a
typical trabecular pattern.
May be solitary, multiple nodules or diffusely
infiltrating.
Alpha- fetoprotein levels are elevated.
80% of HCC occur in cirrhotic liver.
There is propensity toward venous
invasion(PV>HV).

34. USG
 Variable in appearance.
Small <3 cm usually hypoechoic.
A thin ,peripheral hypoechoic halo( fibrous
capsule).
Larger tumors often are heterogeneous
(necrosis,hge & fibrosis).
May invade the portal & hepatic veins.
Most tumor will show central vascularity on
Doppler study.

36. CT SCAN
NECT: large hypodense mass, often with
central area of low attenuation(necrosis).
May be isodense to liver.
CECT: non necrotic area enhances strongly in
arterial phase & early washout in subsequent
phases.
Detection of venous invasion (portal,hepatic
veins,IVC).

40. MRI
• T1WI : variable (fatty
change, internal
fibrosis,hge)
• T2WI : hyperintense
• Capsule : hypo in T1
&T2WI
• CEMR : similar to CECT

41. HCC RNs DPNs
NECT Hypo/ isodense Iso to liver except
siderotic nodule
Hypo to liver but
may be iso or hyper
CECT Early enhancement
in arteial phase &
early washout in
later phases.
Same as liver
parenchyma
Low grade- same as
liver parenchyma
High grade- early
enhancement in
arterial phase but
not early wash out
in delayed phase..
T1WI LOW SI variable High SI
T2WI High(mild to
moderate) SI
Iso/low SI iso/low SI
DWI Restricted diffusion no no

42. • Hepatocellular carcinoma and regenerative nodule.
• T1WI MRI (A) and T2WI MRI (B) demonstrating a
hepatocellular carcinoma (white arrowhead) and an
adjacent atypical regenerativenodule (black
arrowhead).

44. FIBROLAMELLAR CARCINOMA
• Histologic subtype of HCC.
• Found in young adults & adolescents.
• No coexisting liver disease.
• The serum AFP levels are usually normal.
• The prognosis is better compared with HCC.
• Hemorrhage & necrosis –rare.
• A fibrous central scar may present.
• Calcification is common(within the scar in stellate
pattern).

45. USG
• Echogenecity of FLC is variable.
• Puncate calcification & central echogenic scar.
• CT SCAN:
• NECT: well defined ,low density mass with a
more low attenuating central scar.
• CECT: moderate enhancement of the lesion
with delayed enhancement of scar.

49. MRI
• T1WI: Isointense to normal liver.
• T2WI: iso to slightly hyperintense.
• Lac of hemorrhage & necrosis.(HCC-
common).
• Central scar is hypointense in both T1WI &
T2WI due to its fibrous nature.(FNH)

52. HCC FLC
Risk factor Occur in cirrhotic liver Normal liver
Age Old Age Young adult
S.AFP Elevated Normal
Central scar Less common More common
Hemorrhage, necrosis more less
Calcification
Portal vein thrombus
Less common
More common
More common
Less common

53. INTRAHEPATIC
CHOLANGIOCARCINOMA
• An adenocarcinoma, originates in small
intrahepatic ducts.
• 10% of all cholangiocarcinoma.
• Usually large, firm masses with abundant fibrous
tissue. Desmoplastic reaction is prominent.
• Age: 7th decade. M>F.
• Increased incidence- carolis disease, sclerosing
cholangitis, IH calculi & IBD.
• A normal Serum AFP may be helpful in suggesting
ICCA rather than HCC.

54. USG

55. CT SCAN
• NECT: well defined round to oval hypo dense
mass.
• CECT: typically shows early peripheral
enhancement. Centre of the tumor remains
no enhanced (abundant fibrous stroma).
• In delayed phase centre of the tumor is
enhanced.
• Capsule retraction and biliary dilatation
adjacent to mass is highly suggestive of ICCA.

58. MRI
• The tumour is hypointense on T1WI &
hyperintense on T2WI with an irregular
contour.
• Strongly hypeintense areas on T2WI- necrosis.
• DWI: peripherally hyperintense target
appearance.
• CEMRI is similar to CECT.

61. HCC IHCC
Pathology Soft tumor(lack of stroma) Hard mass(abundant
fibrous tissue)
Risk factor Cirrhosis, alcoholism Sclerosing cholangitis
carolies disease,IBD
Hge & necrosis Common rare
Capsular retraction Less common Common(fibrosis)
Vascular invasion common Less common
NECT Hypodense Homogenous hypodense
CECT Early enhancement(Arterial
phase),
early washout( later
phases).
Heterogeneous minor
peripheral enhancement
with gradual enhancement
centrally.

62. hemangioma ICCA metastasis
age Any age Older age(7th
decade)
Older(but can occur
any age)
sex F M M=F
MRI(T2WI) Iight bulb
appearance
Hyperintense Variable
Cystic—light bulb
Post contrast Nodular peripheral
enhancement
Mild heterogenious
peripheral
enhancement,exce
pt central scar
Peripheral rim like
enhancement
Bile duct invasion no common Less common
Capsular retraction No common No

63. Metastases
• Liver is the most common site of metastasis.
• Usually multiple.
• Majorities are hypovascular (GI tract,lung
breast& head,neck tumour, lymphoma).
• Hypervascular metastasis are less .(NET, RCC,
carcinoid, sarcoma, melanoma).
• Calcified metastases are uncommon( colon,
stomach, breast,melanoma).
• Cystic meatstases occur from mucinous ca of
ovary, colon, sarcoma, melanoma).

64. USG
• Sonographic appreance is variable( iso, hypo,
hyperechoic, calcified or cystic).

66. CT SCAN
• NECT: Typically hypodense, may be iso or
hyperdense, cystic, mixed,calcified.
• CECT: Enhancement is typically peripheral in
arterial phase & washout in delayed phase.

68. MRI
• Variable but usually most metastatic nodules
are hypointense on T1W & hyperintense on
T2WI.
• High signal intensity in T1WI- mets from
melanoma, ca colon.
• Higher signal on T2WI- mets with liquifective
necrosis.
• CEMRI: variable.

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