Diagnostic Imaging of the Liver

Mohamed Zaitoun
Assistant Lecturer-Diagnostic Radiology
Department , Zagazig University Hospitals
Egypt
FINR (Fellowship of Interventional
Neuroradiology)-Switzerland
zaitoun82@gmail.com

Knowing as much as
possible about your enemy
precedes successful battle
and learning about the
disease process precedes
successful management

Liver
a) Diffuse Liver Diseases
b) Infections
c) Tumors
d) Trauma
e) Vascular Abnormalities
f) Benign Hepatic Cysts
g) Hepatic Calcifications
h) Hepatomegaly

a) Diffuse Liver Diseases :
1-Hepatitis
2-Cirrhosis
3-Fatty Liver
4-Focal Confluent Fibrosis
5-Glycogen Storage Disease
6-Gaucher’s Disease
7-Hemachromatosis

1-Hepatitis :
a) Causes
b) Radiographic Features

a) Causes :
1-Viral hepatitis :
-Hepatitis A , B & C
-Other viruses : cytomegalovirus, Epstein-Barr,
herpes simplex , rubella , yellow fever
2-Chemical hepatitis :
-Alcohol
-Drugs : INH, halothane , chlorpromazine ,
phenytoin , methyldopa , acetaminophen
-Toxins such as CCl4

b) Radiographic Features : U/S
1-Acute Hepatitis :
-In most cases , the liver appears normal
-The liver parenchyma may have a diffusely
decreased echogenicity with accentuated
brightness of the portal triads (starry sky) ,
periportal cuffing
-Hepatomegaly & thickening of the G.B. wall

2-Chronic Hepatitis :
-In most cases , the liver appears normal
-When cirrhosis develops , U/S may
demonstrate a coarse echotexture & other
morphologic changes of cirrhosis

2-Cirrhosis :
a) Definition
b) Pathology
c) Classification
d) Radiographic Features

a) Definition :
-Diffuse process characterized by fibrosis
and the conversion of normal liver
architecture into structurally abnormal
nodules

b) Pathology :
-3 pathologic mechanisms which in combination
create cirrhosis :cell death , fibrosis &
regeneration
c) Classification :
1-Micronodular (nodule 1 mm to 1 cm) in alcohol
intake
2-Macronodular (up to 5 cm) in chronic viral
hepatitis

d) Radiographic Features :
a) U/S :
1-Volume redistribution
2-Coarse echotexture
3-Nodular surface
4-Nodules
5-Portal hypertension

1-Volume redistribution :
-Early stages , the liver is enlarged
-Advanced stages , the liver is often small with
relative enlargement of the caudate , left lobe or
both in comparison with the right lobe
2-Coarse echotexture :
-Increased echogenicity and coarse echotexture
are frequent observations in diffuse liver disease

3-Nodular surface :
-Irregularity of the liver surface corresponds to the
presence of regenerating nodules and fibrosis
4-Nodules (regenerative & dysplastic) :
-Regenerative nodules (RN) , represents regenerating
hepatocytes surrounded by a fibrous septa (isoechoic or
hypoechoic with a thin echogenic border)
-Dysplastic nodules , considered premalignant , 1 cm , they
contain well differentiated hepatocytes , a portal venous
blood supply and also atypical or frankly malignant cells
5-Portal hypertension :
Ascites , splenomegaly and varices

b) CT :
-CT is insensitive in early cirrhosis
-More established findings : as U/S

3-Fatty Liver :
a) Causes

a) Causes :
1-Obesity (most common cause)
2-Alcohol
3-Hyperalimentation
4-Debilitation
5-Chemotherapy
6-Hepatitis
7-Steroids , Cushing's syndrome

1-U/S :
-The liver echogenicity is higher than normal
, liver parenchyma becomes brighter than
right kidney parenchyma

*N.B. >> Focal fatty change includes :
Focal fatty infiltration and focal fatty
sparing , both may mimic neoplastic
involvement
a) Focal fatty infiltration , regions of
increased echogenicity are present within
a background of normal liver parenchyma

b) Focal fatty sparing , islands of normal
liver parenchyma may appear as
hypoechoic masses within a dense fatty
infiltrated liver

-Features of focal fatty change include :
a) Focal fatty sparing and focal fatty liver , both most
commonly involve the peripheral region of the medial
segment of the left lobe (segment IV)
b) Sparing also occurs commonly by the gall bladder fossa
and along the liver margins
c) Lack of mass effect , hepatic vessels as a rule are not
displaced
d) Geographic margins are present , although focal fat may
appear round , nodular , or interdigitated with normal
tissue
e) Rapid change with time , fatty infiltration may resolve as
early as within 6 days
f) CT scan of the liver will demonstrate corresponding
regions of low attenuation

2-CT :
-Fatty areas are hypodense , normal liver appears
relatively hyperdense
-Liver less dense than spleen
-Hepatic and portal veins appear dense relative to
decreased parenchymal density
-Common focal fatty deposit : segment IV ,
anteriorly near fissure for falciform ligament

4-Focal Confluent Fibrosis :
-Wedge shaped area of low attenuation on
noncontrast CT
-Retraction of overlying liver capsule (90%)
-Located in medial segment of left lobe
and/or anterior segment of right lobe in a
cirrhotic liver
-May show delayed persistent enhancement

-Differential Diagnosis of liver lesions causing
capsular retraction :
1-Metastases
2-HCC (mainly the fibrolamellar type)
3-Cholangiocarcinoma
4-Cirrhosis (confluent hepatic fibrosis)
5-Following trauma (including iatrogenic , e.g.
biliary drainage , biopsy , radiofrequency
ablation)
6-Inflammatory pseudotumor

-Lesion (asterisk) of
lower attenuation than
adjacent liver
parenchyma involving
segment IV and mild
retraction of liver
capsule (arrowhead),
which is typical of
focal confluent
fibrosis

Patient with alcoholic cirrhosis and focal confluent fibrosis , axial unenhanced
CT shows progressive retraction of liver capsule over lesion (arrowhead)
and moderate volume loss

5-Glycogen Storage Disease :
a) Definition

a) Definition :
-Enzyme deficiency results in accumulation
of polysaccharides in liver and other organ

b) Radiographic Features :
1-Primary liver findings :
-Hepatomegaly
-US : increased echogenicity (looks like fatty liver)
-CT : increased density (55 to 90 HU)
2-Other organs :
-Nephromegaly
3-Hepatic complications :
-Hepatic adenoma

6-Gaucher’s Disease :
a) Definition

a) Definition :
-Glucocerebrosidase deficiency leads to
accumulation of ceramide in cells of the
RES

1-Liver :
-Hepatomegaly
2-Spleen :
-Splenomegaly (marked)
-Focal lesions (infarcts) typically have low density (CT) and
are hyperechoic (US)
3-Musculoskeletal :
-Erlenmeyer flask deformity of femur
-Generalized osteopenia
-Multiple lytic bone lesions
-Aseptic necrosis of femoral head

7-Hemachromatosis :
a) Definition
b) Types
c) Radiographic Features

a) Definition :
-Iron overload
b) Types :
1-Primary Hemachromatosis (defect in intestinal
mucosa , increased iron absorption) :
-Clinical finding is bronze diabetes : cirrhosis ,
diabetes mellitus & hyperpigmentation
2-Secondary Hemachromatosis
-Multiple transfusions in bleeders

c) Radiographic Features :
1-US :
-Hyperechoic liver
2-CT :
-Dense liver (>75 HU), much denser than spleen
-Intrahepatic vessels stand out as low-density structures
3-MRI :
-Liver and spleen are markedly hypointense on T2
-Other organs with decreased SI : lymph nodes , bone
marrow , pituitary , heart , adrenals , bowel
-In primary hemachromatosis , pancreas also appears
hypointense

b) Infections :
1-Viral hepatitis
2-Bacterial diseases (pyogenic abscess)
3-Fungal diseases (candidiasis)
4-Parasitic diseases (Amebic abscess ,
Hydatid disease & Bilharziasis)

1-Viral hepatitis :
-See before

2-Bacterial diseases (pyogenic abscess) :
a) Causes

a) Causes :
-Pathogens : Escherichia coli , aerobic
streptococci , anaerobes
-Ascending cholangitis
-Trauma , surgery
-Pylephlebitis

1-U/S :
-Cystic with the fluid ranging from echofree to
highly echogenic
-Occasionally , gas producing organisms give rise
to echogenic foci
Fluid-fluid interfaces , internal septations & debris
have all been observed
-The abscess wall can vary from well defined to
irregular & thick
-May be multiple

2-CT :
-Hypodense mass or masses with peripheral
enhancement , no fill-in
-Double-target sign : wall enhancement
with surrounding hypodense zone
(edema)
-30% contain gas

3-Fungal diseases (candidiasis) :
-In immunocompromised
-Small abscesses spread throughout the
liver

4-Parasitic diseases :
a) Amebic abscess
b) Hydatid disease
c) Bilharziasis

a) Amebic abscess :
1-Etiology
2-Radiographic Features

1-Etiology :
-Pathogen : Entamoeba histolytica
2-Radiographic Features :
-Round or oval-shaped lesion
-Irregular shaggy borders
-Contiguity with the diaphragm , may be
associated with pleural effusion & lung collapse
-Internal septations , 30%
-Multiple abscesses , 25%

b) Hydatid disease : (Echinococcus)
1-Etiology
2-Classification

1-Etiology :
-Caused by infestation by the parasite
Echinococcus granulosus

2-Classification :
a) Simple cyst containing no internal
architecture except sand (fine debris)
b) Cysts with detached endocyst 2ry to
rupture
c) Cysts with daughter cyst matrix
(echogenic material between the daughter
cysts)
d) Densely calcified masses

a) Simple cyst containing no internal
architecture except sand (fine debris)

b) Cysts with detached endocyst 2ry to
rupture

c) Cysts with daughter cyst matrix
(echogenic material between the daughter
cysts)

-Calcification
-Internal floating shadows
-Daughter cysts
-Other cysts (especially in the lung)

c) Bilharziasis :
1-Etiology

1-Etiology :
-Caused by Schistosoma
-Causes periportal fibrosis , fine and coarse

a) U/S :
-Widened echogenic portal tracts , sometimes
reaching a thickness of 2 cm
-The porta hepatis is the region most often
affected
-Initially the liver is enlarged , however as the peri-
portal fibrosis progress , the liver is contracted &
the features of portal hypertension prevails

b) CT :
-Prominent hypodense and hypovascular
periportal tracts secondary to periportal
fibrosis

c) Tumors :
(I) Benign :
1-Cavernous Hemangioma
2-Focal nodular hyperplasia
3-Adenoma
4-Hemangioendothelioma
5-Mesenchymal Hamartoma
(II) Malignant :
1-Hepatocellular Carcinoma (HCC)
2-Mets
3-Lymphoma
4-Hepatoblastoma

*How to detect the site of the focal >>
Couinaud system >>
-The liver is divided by the branches of the hepatic veins
into 8 segments starting at the caudate lobe & running in
clock-wise direction
-LT lobe :
*Segment I >> caudate lobe
*Segment II & III divided by LT PV >>
the furthest left
II >> lateral superior
III >> lateral inferior

*Segment IV >>
-Lies between the LT hepatic vein & middle
hepatic vein
-Separated from segment II & III by the LT
hepatic vein
-IVa >> medial superior
-IVb >> medial inferior
Divided by the LT PV

-RT lobe :
*Segment V >> anterior inferior
*Segment VI >> posterior inferior
*Segment VII >> posterior superior
*Segment VIII >> anterior superior
The RT lobe is divided by >>
> RT hepatic vein into : antero-medial & postero-
lateral
> RT branch of PV into : superior & inferior

(I) Benign :
1-Cavernous Hemangioma
2-Focal nodular hyperplasia
3-Adenoma
4-Infantile Hepatic Hemangioendothelioma
5-Mesenchymal Hamartoma

1-Cavernous Hemangioma :
a) Incidence

a) Incidence :
-Most common benign tumor of the liver
-80% in females , hemangiomas may enlarge
particularly during pregnancy or estrogen
administration
-Two types :
1-Typical Hemangioma : Common
-Small , asymptomatic , discovered incidentally
2-Giant Hemangioma : > 5 cm
-Uncommon

1-U/S :
-Small < 3 cm , well defined , homogenous
and hyperechoic
-Giant hemangiomas are heterogeneous
-Posterior acoustic enhancement is
common

2-CT : Fill in sign
-Noncontrast : often hypoattenuating relative to
liver parenchyma
-Arterial phase : typically discontinuous , nodular ,
peripheral enhancement (small lesions may
show uniform enhancement)
-Portal venous phase : progressive peripheral
enhancement with more centripetal fill in
-Delayed phase : further irregular fill in and
therefore iso or hyperattenuating to liver
parenchyma (fill in sign)

3-MRI : Light-bulb sign
-Hyperintense (similar to CSF) on heavily T2
(light-bulb sign)
-Post-gadolinium peripheral nodular
enhancement with centripetal fill-in
-Imaging modality of choice

2-Focal Nodular Hyperplasia :
a) Incidence

a) Incidence :
-The 2nd
most common benign liver mass
after hemangioma
-More common in women in childbearing
period

1-U/S :
-Often a subtle liver mass that is difficult to
differentiate from in echogenicity from the
adjacent liver parenchyma
-The central scar may be seen as a
hypoechoic linear or stellate area within
the central portion of the mass , on
occasion may be hyperechoic

-Doppler : highly suggestive, in that well
developed peripheral and central blood
vessel larger are seen , the blood vessels
can be seen to course within the central
scar which either a linear or stellate
configuration (spoke-wheel vascularity)

2-CT :
-Non-contrast : hypo or isodense but may
appear hyperdense if the rest of the liver is
fatty , a hypodense central scar can be
seen in up to 60% of lesions over 3 cm in
size
-Arterial : FNH demonstrates bright arterial
contrast enhancement except for the
central scar which remains hypodense
-Portal : the lesion becomes isodense to
liver
-Delayed : the scar demonstrates
enhancement on delayed scans in up to
80% of cases

3-MRI :
-Lesion isointense to liver , central scar
hyperintense on T2
-Arterial enhancement
-Delayed enhancement of central scar
-Angiography : hypervascular lesion

Axial T2 shows a large FNH lesion (straight arrow) that is isointense
relative to the surrounding liver parenchyma, the central scar
(curved arrow) has slightly higher signal intensity than the lesion

3-Adenoma :
a) Incidence

a) Incidence :
-Less common than FNH
-More common in women , increase incidence now due to
usage of oral contraceptive agents
-Anabolic steroids (typically young men) , Glycogen storage
disease
-The tumor may be asymptomatic , but often the patient or
the physician feels a mass in the right upper quadrant
-Pain may occur as a result of bleeding or infarction within
the lesion , the most alarming manifestation is shock
caused by tumor rupture and hemoprotineum

1-U/S :
-Solitary and large at the time of diagnosis (5-15cm)
-Non specific , the echogenicity may be hyperechoic (most
common) , hypoechoic , isoechoic or mixed
-With hemorrhage , a fluid component may be evident
within or around the mass and free intraperitoneal blood
may be seen
-A hypoechoic halo of focal fat sparing is also frequently
seen
-Colour Doppler may show perilesional sinusoid

2-CT :
-Unenhanced : they are well marginated and
isoattenuating to liver
-On contrast administration they demonstrate
transient relaitvely homogenous enhancement
returning to near isodensity on portal venous
and delayed phases
-The density of these tumors is variable depending
on :
Fresh hemorrhage , may be hyperdense
Fat content may make the mass hypodense
3-MRI :
-High in T1 & T2

4-Infantile Hepatic
Hemangioendothelioma :
a) Incidence

a) Incidence :
-It is a rare tumor that may occur as a
solitary lesion or multifocal nodules
ranging in size from few mm upto 15 cm
-Most common benign pediatric liver tumor
-85% present at < 6 months
-Associated cutaneous hemangiomas in
50%

1-US :
-Appears as a complex, mostly solid hepatic lesion
with variable hypo- and hyperechoic echotexture
-In cases of significant arteriovenous shunting,
dilated hepatic vasculature with prominent blood
flow at Doppler US is typical
-If large vascular spaces are present, anechoic
regions with detectable flow may be seen
-The lesions are often well demarcated from the
surrounding liver parenchyma

Transverse US image shows several small, well-demarcated,
homogeneous hypoechoic lesions (arrowheads) in the liver

Color Doppler image shows peripheral flow around some of
the lesions

Diffuse form of Hemangioendothelioma in a 10-week-old girl with severe
hypothyroidism, (a, b) Transverse (a) and longitudinal (b) US images show
numerous large masses (* in a) replacing the liver and compressing the
inferior vena cava (arrow in a), AO in a = aorta, (c) Longitudinal color
Doppler image shows a direct portal vein-to-hepatic vein shunt

2-CT :
-At unenhanced CT, manifests as a well-defined
mass that is hypoattenuating relative to the
normal liver parenchyma, in about 16%-40% of
cases, the lesion is heterogeneous with central
high-attenuation areas due to hemorrhage or
calcifications
-At contrast-enhanced CT, the enhancement
pattern may resemble that of an adult giant
hemangioma, with “nodular” peripheral puddling
of contrast material in the early phase,
subsequent peripheral pooling, and central
enhancement with variable delay, in larger
tumors, central enhancement is often lacking
due to fibrosis, hemorrhage, or necrosis,
conversely, small lesions, which tend to be
multifocal, frequently enhance completely and
typically do not demonstrate hemorrhage or
necrosis

CT+C, obtained in the early portal venous phase, shows peripheral
corrugated enhancement of the masses (arrowheads) and
compression of the inferior vena cava (arrow), (e) Delayed phase
CT image shows centripetal enhancement of the masses

Axial CT scan post-contrast arterial phase at the level of the kidneys
showed diffused hepatic masses with intense peripheral
enhancement and central non-enhancing areas, B) Venous phase
shows diffused enhancement of the lobulated liver segments

3-MRI :
*T1 : low signal intensity
*T2 : high signal intensity
-In tumors with arteriovenous shunting and high
blood flow, flow voids may be observed on T2
-Because of the simultaneous presence of
hemorrhage, necrosis, and fibrosis, the mass
often appears heterogeneous on both T1 & T2
*T1+C : the lesions usually show an enhancement
pattern similar to that described at CT

A) Axial unenhanced T1 shows diffused nodules with low signal
intensity, B) Coronal T2 shows diffuse high signal intensity nodules
occupying almost the entire abdomen

A) Axial MRI fat suppression shows diffused high signal nodules, B)
Sagittal MRI post gadolinium shows enhancement of the nodules

5-Mesenchymal Hamartoma :
a) Incidence

a) Incidence :
-2nd
most common benign tumor in pediatric
population
-It typically occurs in children and neonates,
with most cases presenting within the first
two years of life
-Male predominance (2:1)

-Mesenchymal hamartomas can show a wide
spectrum of radiological features, from being :
1-Predominantly cystic tumor, to
2-Multiseptated cystic tumor, to
3-Mixed solid and cystic tumor, to
4-Even a completely solid tumor
-The dominant radiographic pattern, however, is a
large (often around 12-15 cm), predominantly
cystic mass with internal septations, there can
be considerable variation in the size of septae
and cystic spaces

1-US :
-It usually appear as a multiseptated cystic
lesion interspersed with solid components
2-CT :
-On unenhanced CT, it usually has a
heterogeneous appearance, the stromal
elements often appear hypoattenuating,
whereas the cystic components have
water attenuation, the appearance of
cystic and solid portions has been likened
to Swiss cheese
-On a postcontrast CT scan, solid portions
or thick septa of the tumors can show
heterogeneous enhancement

(a) Transverse US image shows cystic (arrowheads) and
solid (T) portions of the tumor and adjacent normal liver (*),
(b) Longitudinal color Doppler image shows no flow to the cystic
component, which contains low-level echoes (arrowhead), minimal
flow is seen in the solid component (arrows)

Mesenchymal hamartoma in a 2-year-8-month-old boy, A. US shows a large,
multiseptated cystic tumor in the right lobe of the liver. The septa of the
tumor (arrows) are very thin and regular in thickness, B. CT+C shows a
large cystic tumor with fine enhancing septa (arrows) in the liver, there is no
solid portion or calcification within the tumor

Mesenchymal hamartoma in a 7-year-2-month-old boy, A. US shows a huge, mixed solid
and cystic tumor, the echogenic materials and fluid-fluid levels (arrows) are noted in
the cystic portions of the tumor, the solid portion of the tumor is hyperechoic (*),
B. Color Doppler US shows vascularity along the thick septa and solid portion of the
tumor, C. A pre-contrast CT scan shows a low attenuating tumor in the right lobe of
the liver, note the fluid-fluid levels due to an intracystic hemorrhage within some of
the cystic areas (arrows), D. On a post-contrast CT scan, the solid portion of the
tumor shows heterogeneous enhancement (arrows)

Coronal CT image obtained with intravenous and oral contrast material
shows the mixed cystic (arrowheads) and solid (T) tumor replacing
the left hepatic lobe, * = normal live

3-MRI :
-The appearance of mesenchymal hamartoma
depends on the cystic versus stromal
(mesenchymal) composition of the mass, as well
as the protein content of the fluid in the cysts
-Solid portions may appear hypointense to
adjacent liver on both T1 and T2 owing to
fibrosis
-The cystic portions are generally close to water
signal intensity on T2 and demonstrate variable
signal intensity on T1, depending on the protein
content of the cyst fluid
-After intravenous administration of gadolinium
contrast material, enhancement is mild and
limited to the septa and stromal components

Mesenchymal hamartoma of the liver in a 2-year-old boy, * = normal
liver, (a) Axial T2 shows the markedly hyperintense mass
containing thin septa (arrows), (b) Coronal T1 shows that the mass
(arrows) is homogeneously hypointense relative to the
liver, (c) Coronal T1+C obtained at the same level shows that
enhancement is limited to the septa (arrows)

These (a) coronal and (b) axial T2 exquisitely depict the massive size
of the mesenchymal hamartoma with multiple cystic areas (C) of
varying sizes, few solid areas (S) and internal septations, the solid
areas are hyperintense to normal liver (L)

(a) T2 shows hyperintensity, (b) T1 shows hypointensity

(II) Malignant :
1-Hepatocellular Carcinoma (HCC)
2-Mets
3-Lymphoma
4-Hepatoblastoma
5-Angiosarcoma

1-HCC :
a) Incidence
c) Fibrolamellar HCC

a) Incidence :
-One of the most common malignant tumors
-More in men
-Incidence : Alcoholic cirrhosis
Hepatitis B & C

1-U/S :
-Typically a small focal HCC appears
hypoechoic compared to normal liver
-Larger lesions are heterogeneous due to
fibrosis , fatty change , necrosis and
calcification
-A peripheral halo of hypoechogenicity may
be seen with focal fatty sparing

2-CT :
-Several pattern may be seen :
a) Focal HCC :
-Large usually hypodense mass
-May have necrosis , fat , calcification
b) Multifocal HCC :
-Multiple masses of variable attenuation lesions
-May also have central hypodense necrotic
portions
c) Diffuse HCC :
-May be difficult to distinguish from associated
cirrhosis

-Enhancement pattern is the key to correct
assessment of HCC , usually the mass
enhances vividly during early arterial (25
seconds) and then washes out becoming
indistinct or hypodense compared to the
rest of the liver at the portal phase

3-MRI :
-T1 : Hypo , iso or Hyper (due to fat
degeneration)
-T2 : Hyperintense
-T1+C : enhancement is usually arterial and
may be brief , rapid wash out becoming
hypointense c.f. remainder of the liver
(96% specific) , this is on account of the
supply to HCC being from the hepatic
artery rather than portal vein
4-Angiography : Hypervascular , AV
shunting is typical & dilated arterial supply

42-year-old man with HCC and hepatitis B-related cirrhosis: multiphasic MR technique
with gadoxetate disodium. (a, b) Gadoxetate disodium-enhanced T1-weighted 3D
GRE show large hypointense mass on (a) precontrast image with (b)
hyperenhancement in late hepatic arterial phase, (c) Portal venous
and (d) transitional phase images show apparent washout of contrast material from
tumor, (e) Mass is hypointense relative to strongly enhanced liver parenchyma on
hepatobiliary phase image obtained at 20 minutes after injection

**N.B. :
-MRI allows differentiation of dysplastic nodules from HCC
as the dysplastic nodules are :
1-Hyperintense on T1
2-Hypointense on T2
3-Lack of enhancement in the arterial phase
4-Enhance in the portal venous phase and appear
iso/hyperintense to liver parenchyma
-The regenerative nodules have variable intensity on T1,
hypointense on T2 with an enhancement pattern similar
to normal liver parenchyma and without abnormal
enhancement during the arterial phase

MRI of the dysplastic nodule, (a) T1 showing a hyperintense dysplastic
nodule in the left lobe of the liver, (b) Nodule is characteristically
hypointense on T2, (c) Non enhancing after IV gadolinium
administration

Small HCC in segment 8 of the liver, (a) T1 showing a small
hypointense nodule adjacent to the right hepatic vein, (b) Nodule is
characteristically hyperintense on T2, (c) Enhancement during
arterial phase after administration of IV gadolinium

c) Fibrolamellar HCC :
1-Incidence
3-Differential Diagnosis

1-Incidence :
-Typically these tumors occur in young
adults (20 to 40 years of age)
-Unlike HCC they do not have an
association with cirrhosis, alcoholism or
hepatitis B / C infection, i.e. it occurs in a
non-cirrhotic liver

a) US
b) CT
c) MRI

a) US :
-Fibrolamellar HCCs have nonspecific
sonographic features and are seen as
well-defined masses of variable
echogenicity on ultrasound
-Multiphasic CT using a liver protocol or
dynamic contrast-enhanced MRI is usually
required for further characterization

Fibrolamellar hepatocellular carcinoma (HCC) in 23-year-old woman,
transverse gray-scale ultrasound image shows large heterogeneous
echogenic lesion (curved arrow) in liver, echogenic strands in center
of lesion (straight arrow) represent central scar, ultrasound features
of fibrolamellar HCC are usually nonspecific

b) CT :
-Usually present as large heterogeneous lesions (mean
diameter, 13 cm)
-Most of these tumors are well defined and have a
lobulated outline, however, fibrolamellar HCC may also
be ill-defined
-The tumors are predominantly hypoattenuating on the
unenhanced images
-Calcification is commonly seen
-Central stellate scar is typically seen, the presence of a
central scar is not pathognomonic of fibrolamellar HCC
and has been reported in many benign and malignant
liver lesions, however, a large scar (width > 2 cm) and
presence of radiating fibrotic bands or septa are more
common in fibrolamellar HCC
-Furthermore, presence of calcifications within the central
scar is a useful diagnostic feature
-Tumor necrosis may be seen, but intratumoral
hemorrhage is uncommon

Fibrolamellar hepatocellular carcinoma in 16-year-old girl, A, Axial unenhanced
CT shows hypoattenuating mass (arrow) with central calcification
(arrowhead), B, Axial CT+C in arterial phase shows that tumor (curved
arrow) is hyperattenuating compared with liver parenchyma, central scar
does not show any enhancement (straight arrow), C, Axial CT+C in portal
phase shows tumor is still hyperattenuating (curved arrow) compared with
adjacent liver parenchyma (straight arrow), D, Axial CT+C in delayed phase
shows washout in mass (curved arrow), which is now hypoattenuating.
Central scar shows delayed enhancement (straight arrow)

(a) Unenhanced, (b) Arterial phase, (c) Venous phase, (d)
equilibrium phase

c) MRI :
*T1 : hypointense
*T2 : hyperintense
-The fibrous central scar is typically hypointense
on both T1 and T2
-This feature can help to distinguish fibrolamellar
HCC from FNH because the central scar in the
latter is predominantly T2 hyperintense, the
presence of intralesional fat has not been
reported in fibrolamellar HCC
*T1+C : contrast enhancement characteristics of
fibrolamellar HCC mimic the patterns seen on
CT, showing marked heterogeneous contrast
enhancement on the arterial phase and
becoming isointense or hypointense on the
portal venous and delayed phase

27-year-old woman with fibrolamellar hepatocellular carcinoma, coronal
T1+C shows hypervascular mass (arrow) with central scar, tumor
thrombus is present in portal vein (arrowhead)

Fibrolamellar hepatocellular carcinoma in 29-year-old man, A, Axial T1 shows mildly hypointense
heterogeneous mass in liver (arrow) containing T1-hypointense central scar (arrowhead), B, Axial
T2 shows that tumor (arrow) has heterogeneous high signal intensity, central scar is hypointense
on T2 (arrowhead), C, Axial 3D gradient-echo fat-saturated T1+C in arterial phase shows
heterogeneous enhancement within mass (arrow), no enhancement is seen within central scar
(arrowhead), D, Axial T1+C in portal phase shows that tumor (arrow) is mildly hyperintense
compared with liver, partial enhancement is seen in central scar (arrowhead), E, Axial T1+C in
delayed phase shows that tumor (arrow) is isointense to mildly hyperintense compared with liver.
Central scar shows almost complete enhancement (arrowhead)

3-Differential Diagnosis :
From liver lesions with a central scar
1-FNH
2-Hemangioma (especially if large)
3-HCC (Fibrolamellar type)
4-Cholangiocarcinoma (peripheral type)
5-Hepatic adenoma , metastases
(occasionally)

2-Metastases :
a) Incidence

a) Incidence :
-18 to 20 times more common than HCC
-The most common primary tumor sites :
GB , Colon , Stomach , Pancreas , Breast &
Lung

1-U/S :
a) Echogenic metastases
b) Hypoechoic
c) Target
d) Calcified
e) Cystic
f) Diffuse

a) Hyperechoic :
-Gastrointestinal origin or from HCC
-The more vascular the tumor , the more
likely the lesion to be echogenic
-Renal cell carcinoma , carcinoid ,
choriocarcinoma , vascular primaries &
islet cell carcinoma

b) Hypoechoic :
-Hypovascular
-Breast , lung , lymphoma , esophagus , stomach
& pancreas
-Multiple hypoechoic hepatic masses is more
typical of primary NHL of the liver or lymphoma
associated with AIDS , however lymphomatous
masses may appear anechoic & septated ,
mimicking hepatic abscesses

c) Bull’s eye (target pattern) :
-Peripheral hypoechoic zone
-The appearance is nonspecific & common ,
although it is frequently identified in
metastases from bronchogenic carcinoma

d) Calcified metastases :
-Marked echogenicity & distal acoustic shadowing
-Mucinous adenocarcinoma , osteosarcoma ,
chondosarcoma , teratocarcinoma ,
neuroblastoma
-Calcium may appear as large , echogenic &
shadowing foci or more often shows
innumerable tiny punctate echogenicities without
clear shadowing

e) Cystic metastases :
-Necrosis in sarcoma , cystic growth pattern
as in cystadenocarcinoma of ovary &
pancreas & mucinous carcinoma of colon

f) Diffuse (infiltrative) :
-Breast , lung & malignant melanoma
-The diagnosis can be difficult if the patient
has a fatty liver from chemotherapy

2-CT :
-Best seen on portal venous phase images
except for hypervascular lesions (arterial
phase)
-Small lesions may fill in on delayed scans
-Peripheral washout sign (when seen) is
characteristic of metastases

3-Lymphoma :
-Secondary involvement occurs in up to 50
% of patients with systemic lymphoma ,
but it frequently occult , primary hepatic
lymphoma is very rare
-Multiple hypoechoic hepatic masses + solid
masses at the spleen , kidney , chest …
+ lymphadenopathy

NHL in a 16-year-old girl, (a) US scan shows a large hypoechoic
nodule (M) in the right hepatic lobe, K = kidney, L = liver, (b) CT+C
shows low-attenuation nodular lesions (arrowheads), a few discrete
lesions are evident in both hepatic lobes, with small nodules in the
spleen and right kidney

4-Hepatoblastoma :
1-Incidence

1-Incidence :
-Most common primary malignant liver
tumor in children
-Age : < 2 years

a) US :
-Large hepatic mass
-Mixed echogenicity (US), often hyperechoic
relative to adjacent liver
b) CT :
-Sharply circumscribed mass that is slightly
hypoattenuating relative to adjacent liver
parenchyma on unenhanced & contrast
enhanced, septa and periphery of the tumor may
enhance
-Calcification , 50%
-Metastases : lungs > lymph nodes , brain

Transverse US image shows the hyperechoic mass with a lobular
margin and hypoechoic septa (arrowheads), arrow = portal vein

(a) Axial CT image obtained in the arterial phase of enhancement
shows a circumscribed slightly hypoattenuating mass (arrowheads),
(b) CT image obtained in the portal venous phase shows more
heterogeneous, lobular enhancement (arrowhead), although the
mass is still hypoattenuating relative to adjacent liver

c) MRI :
*T1 : hypointense
*T2 : hyperintense ,septa are hypo in T1 &
T2 and enhance, hemorrhage appears
hyperintense in T1
*T1+C : the septa enhance

(a) CT+C shows that the tumor enhances less than normal liver, some
septa enhance (arrowheads), (b) Coronal T2 shows hyperintense
nodules with hypointense septa in between (arrowheads),
(c) Coronal T1+C shows enhancement of the septa and capsule
(arrowheads)

5-Angiosarcoma :
a) Incidence :
-Angiosarcoma is a rare malignant tumor of
vascular origin that can arise anywhere in
the body, including the liver
-Most commonly affecting elderly men

1-US :
-May reveal multiple nodules, a large mass,
or both or diffuse heterogeneous
echotexture of the entire liver
-The echogenicity of the nodules varies
depending on the amount of hemorrhagic
or necrotic change

2-CT & MRI:
-At unenhanced study, the nodules are
generally hypoattenuating to normal liver
but may contain hyperattenuating foci,
which represent acute hemorrhage
-Enhanced study: mimics the intense
peripheral nodular enhancement pattern
of cavernous hemangioma

63-year-old man with multifocal angiosarcoma, (A) Unenhanced helical CT scan shows
multiple masses (arrows) that are hypoattenuated to liver and hypo- and
isoattenuated to vessels, (B) Arterial phase CT+C shows heterogeneous
enhancement of tumors (long arrows), most of which are hyperattenuated to normal
liver but hypoattenuated to aorta, one lesion (short arrow) is hypoattenuated to both
liver and aorta, (C) Portal venous phase contrast-enhanced helical CT scan shows
that most lesions that were hyperattenuated in B (long arrows) are now nearly
isoattenuated to liver, but are hypoattenuated to vessels., large lesion (short arrow)
remains hypoattenuated to both liver and vessels

54-year-old man with multifocal angiosarcoma, arterial phase (A) and portal
venous phase (B) CT+C show large infiltrative mass (large straight arrows)
involving entire left hepatic lobe, small mass (small straight arrow) in right
hepatic lobe, and splenic metastasis (curved arrow), tumors are
hypoattenuated to surrounding liver and aorta, note masses remain
hypoattenuated to surrounding liver and aorta during portal venous phase
(B)

Angiosarcoma in a 62-year-old man, transverse CT+C shows multiple
hypoattenuating liver lesions, some with foci of enhancement
(arrowheads), which are of decreased attenuation compared with
the aorta

Angiosarcoma associated with a chronic organized subcapsular hematoma (arrowheads)
in a 76-year-old man, (a) Transverse CT in the portal phase demonstrates a
heterogeneous enhancement pattern in the lesion (arrows), (b) Transverse contrast-
enhanced dynamic delayed-phase CT scan demonstrates progressive enhancement
over time (arrows), (c) Transverse T1 shows a massive tumor (arrow) in the vicinity of
a chronic organized subcapsular hematoma (arrowheads), the lesion contains focal
areas of high intensity, which suggest hemorrhage, (d) Transverse fat-saturated T2
shows the marked heterogeneous appearance of the lesion (arrows) and hematoma
(arrowheads)

(a) Axial T1 shows a well-defined focus of high signal intensity
(arrowhead) at the margin of the tumor, a finding consistent with
hemorrhage, * = normal liver, (b) Coronal T2 shows that the mass is
predominantly hyperintense with dark septa (arrowheads). * =
normal liver

Angiosarcoma in a 37-year-old man with known aplastic anemia, (a)
Transverse T1 shows a diffuse lesion involving almost the entire posterior
segment of the right lobe of the liver, numerous small nodules of high
intensity suggest a focal area of hemorrhage, diffuse decrease in signal
intensity in the liver, spleen (not shown), and bone marrow is consistent with
patient’s known secondary hemochromatosis, (b) Transverse fat-saturated
T2 shows compartmentalization within the lesion that contains numerous
focal areas of high intensity

Angiosarcoma in a 65-year-old man, (a) Transverse T1 shows multiple
low-intensity lesions (arrows) that contain focal areas of slightly high
T1, (b) Transverse fat-saturated T2 shows heterogeneous signal
intensity throughout the dominant mass, fluid-fluid levels can be
seen in smaller satellite lesions (arrows)

d) Trauma :
1-Incidence
2-Types
3-Grading

1-Incidence :
-The liver is the most common
intraabdominal site of injury , however ,
one must inspect other organs (spleen ,
bowel) for coexistent trauma
-The predominant site of hepatic injury in
blunt trauma is the right lobe in particular
the posterior segment

2-Types :
a) Laceration (most common)
b) Hematoma , subcapsular or
intraparenchymal
c) Active hemorrhage
d) Major hepatic vein injury
e) AV fistula

a) U/S :
- < 24 hrs following injury , the fresh hemorrhage is
echogenic
- Within the 1st
week , the hepatic laceration
becomes more hypoechoic & distinct as a result
of resorption of devitalized tissue & ingress of
intestinal fluid
- At 2 or 3 weeks later , the laceration becomes
increasingly indistinct as a result of resorption of
the fluid & filling of the spaces of the granulation
tissue

b) CT :
-Lacerations appear as irregular linear /
branching areas of hypoattenuation
-Hematomas appear as a hypodensity
between the liver and its capsule (and can
be differentiated from intra-peritoneal
hematoma as these distort the liver
architecture) or can be intraparenchymal
-Acute hematomas / hemorrhage are
typically hyperdense (40-60HU) compared
to normal liver parenchyma

Lacerations can be stellate , like the example on the left or branching like the
one on the right

CT+C shows linear low-attenuation defect crossing the posterior aspect
of the right lobe of the liver representing a laceration

CT+C shows multiple linear and branching low-attenuation
areas in the right hepatic lobe (arrows) that represent
lacerations

CT+C shows multiple subcapsular hematomas in the right and left
hepatic lobes (arrows) , multifocal intraparenchymal hematomas are
also seen (arrowheads)

CT+C shows a 5-cm intraparenchymal hematoma in the medial
segment of the left hepatic lobe (arrow) , arrowheads indicate
associated hemoperitoneum in the right subphrenic space

Unenhanced CT shows a high-attenuation hematoma in the anterior
segment of the right hepatic lobe (arrow) , note the halo of low
attenuation surrounding the hematoma (arrowheads)

e) Vascular Abnormalities :
1-Portal Hypertension
2-Portal Vein Thrombosis
3-Budd-Chiari Syndrome (BCS)
4-Arterio-Portal Shunting in Liver
5-Hepatic Artery Aneurysm

1-Portal Hypertension :
a) Definition
b) Etiology
c) Radiographic Features

a) Definition :
-Hepatic wedge pressure >10 mm Hg
b) Etiology :
1-Presinusoidal
2-Sinusoidal
3-Postsinusoidal

1-Presinusoidal :
-Portal vein thrombosis
-Extrinsic compression of portal vein
-Schistosomiasis
2-Sinusoidal :
-Cirrhosis
3-Postsinusoidal :
-Budd-Chiari syndrome
-Congestive heart failure

c) Radiographic Features :
-PV diameter > 13 mm
-Portosystemic venous collaterals (Varices) :
gastro-oesophageal junction , para-
umbilical vein , spleno-renal & gastro-renal
, intestinal & hemorrhoidal
-Splenomegaly
-Ascites
-In CT, contrast enhancement of
paraumbilical vein (pathognomonic)

Recanalized paraumbilical vein

2-Portal Vein Thrombosis :
a) Etiology

a) Etiology :
-1-Malignancy (HCC , liver mets , CA
pancreas)
2-Cirrhosis
3-Chronic pancreatits, hepatitis
4-Septicemia , trauma , splenectomy
5-Portocaval shunts , pregnancy

1-U/S :
-Acute thrombosis may be difficult to detect with
grey-scale imaging alone as the thrombus will be
hypoechoic , with time it becomes more
echogenic and easier to detect
-Colour Doppler will of course be able to
demonstrate absent flow in the portal vein and
even detect partial thrombosis

-Cavernous Transformations of the PV :
numerous wormlike vessels at the porta
hepatis which represent periportal
collateral circulation , this pattern is
observed in long standing thrombosis
requiring up to 12 months to occur , so it is
more likely to develop with benign disease

2-CT :
-Non-contrast scans are usually incapable of
demonstrating the thrombus, except is
some acute cases where the thrombus is
hyperdense
-The diagnosis can only reliably be made on
portal venous phase contrast enhanced
studies , complete or partial non-
opacification of part of or the whole portal
vein and its branches

-Importantly the thrombus itself should not
enhance , if enhancement is present then this
strongly suggests that the thrombus is not bland
but rather represents tumor thrombus most
frequently from HCC
-Cavernous transformation appears as multiple
small periportal vessels which represent dilated
collateral veins
-Associated findings of portal hypertension may of
course be evident

Cavernous transformation of the PV

3-Budd-Chiari Syndrome (BCS) :
a) Definition
b) Clinical Picture
c) Etiology
d) Radiographic Features
e) Differential Diagnosis

a) Definition :
-Occlusion of the lumina of the hepatic veins
with or without occlusion of the lumen of
the IVC

b) Clinical Picture :
1-Ascites
2-Pain
3-Hepatomegaly
4-Splenomegaly

c) Causes :
1-Idiopathic : 50%-75%
2-Secondary : 25%-50%
-Coagulation anomalies , clotting disorders ,
polycythemia
-Tumors : HCC , RCC
-Trauma
-Oral contraceptives , chemotherapy

d) Radiographic Features :
1-U/S :
-Partial or complete inability to see the hepatic
veins , stenosis with proximal dilatation , intra-
luminal echogenicity , thickened walls ,
thrombosis & extensive intra-hepatic collaterals
-Hemorrhagic infarction appears hypoechoic by
US
-Caudate lobe is often spared (emissary veins
drain directly into the IVC) and appears enlarged
, small right lobe

2-CT : Mottled appearance
-Inhomogeneous mottled liver with delayed
enhancement in the periphery of the liver and
around the hepatic veins = nutmeg liver
(contrast is prevented from diffusing through the
liver in a normal manner , this results in a
mottled pattern of contrast enhancement in the
arterial and early portal venous phase with
decreased enhancement of the liver periphery)

-Peripheral zones of the liver may appear
hypoattenuating because of reversed
portal venous blood flow
-Caudate lobe enlargement and increased
contrast enhancement compared with the
remainder of the liver
-Inability to identify hepatic vein

CT+C of 30-year-old woman with Budd-Chiari syndrome, note patchy
enhancement of liver (arrow) and absence of hepatic veins, Asterisk
= presence of ascites

CT+C of 30-year-old woman with Budd-Chiari syndrome. Note massive
enlargement of caudate lobe (CL) and patchy enhancement of liver
(arrow). Asterisk = presence of ascites, arrowhead = inferior vena
cava

CT+C of 19-year-old woman with subacute Budd-Chiari syndrome.
Note absence of hepatic veins, enlargement of liver, compression of
inferior vena cava, and presence of ascites (asterisks), Arrowhead =
inferior vena cava

15-year-old girl with acute Budd-Chiari syndrome who presented with acute
inferior vena cava (IVC) thrombosis, A, CT+C shows enlarged caudate lobe
(CL) and lack of opacification of IVC; these findings indicate presence of
acute thrombosis, Arrowhead = thrombosed IVC, B, CT+C obtained at lower
level than A shows extension of IVC thrombosis down to level of renal veins,
renal veins are also thrombosed (arrowheads)

44-year-old woman with Budd-Chiari syndrome, axial CT+C show enlarged liver (arrow)
with heterogeneous enhancement with central hyperattenuation, note caudate lobe
(CL) enlargement, large gastric varices (arrowhead, B), and lack of visualization of
hepatic veins and inferior vena cava (IVC)

CT+C shows ascites and stronger enhancement in the caudate lobe
and central portion of the liver parenchyma than in the periphery

CT+C shows patchy enhancement of the liver parenchyma,
hypertrophy of the left hepatic lobe and thrombosis of the hepatic
veins and IVC (arrow)

Early and delayed phases of liver enhancement

e) Differential Diagnosis :
-Hepatic venoocclusive disease which
causes progressive occlusion of small
vessels , is clinically indistinguishable from
BCS
Caused by :
1-Bone marrow transplantation
2-Chemotherapy
3-Jamaican bush tea

4-Arterio-Portal Shunting in Liver :
a) Definition
b) Types

a) Definition :
-Refers to abnormal shunt or fistulous
connection between the portal venous
system and a hepatic arterial system
within the liver

b) Types :
1-Tumorous Shunt :
-Occurs with hepatocellular carcinoma
-Trans-tumoral shunt is due to abnormal communication
between the feeding artery and draining vein of the
tumor which results in increased vascularity around the
tumor manifested as peritumoral transient hepatic
attenuation differences (THAD)
-The portal vein may show early enhancement in dynamic
arterial scan without enhancement of its main tributaries
the splenic and superior mesenteric veins
-THAD refer to areas of parenchymal enhancement visible
during the hepatic artery phase on helical CT , they are
thought to be a physiological phenomenon caused by
the dual hepatic blood supply , occasionally they may be
associated with hepatic tumors such as HCC

PV enhancement during arterial phase

2-Non-Tumorous Shunt :
-Mainly due to liver biopsy and other hepatic
intervention
-Also may occur due to liver cirrhosis

5-Hepatic Artery Aneurysm :
-Decreasing order of frequency of
abdominal aneurysms : aorta > iliac artery
> splenic artery > hepatic artery
-10% of patients with hepatic artery
aneurysm have sudden rupture
-Hepatic pseudoaneurysm may occur
secondary to pancreatitis

Hepatic artery aneurysm, (a) Left anterior oblique digital subtraction
angiogram obtained with the catheter in the distal CHA shows a
right hepatic artery branch aneurysm (arrowhead), (b) Digital
subtraction completion angiogram shows exclusion of the aneurysm
with use of the sac-packing coil embolization technique (arrowhead)

f) Benign Hepatic Cysts :
1-Simple cyst
2-Polycystic Liver Disease (PLD)
3-Hydatid cyst
4-Abscess (Pyogenic & Amebic)

1-Simple cyst >>
- Def. : fluid filled space having an epithelial lining
- U/S :
*Anechoic with a well demarcated thin wall & posterior
acoustic enhancement
*If complicated with hemorrhage or infection >> internal
echoes & septations , thickened wall or may appear solid
*If thick septae or nodules are seen within the cyst >> CT is
recommended as biliary cystadenoma & cystic
metastases must be considered in the differential
possibilities for complex appearing liver cysts

2-Polycystic Liver Disease (PLD) :
-Usually associated with polycystic kidney disease
but may also occur as an isolated finding in a
rarer genetically distinct disease
-U/S :
*Massive hepatomegaly with innumerable ,
predominantly simple cysts are present
*Portal vein patency should be assessed ,
compression of the main portal vein may result
in portal hypertension as well as associated
findings such as splenomegaly and ascites

3-Hydatid cyst :
-See before
4-Abscess ( Pyogenic & Amebic ) :
-See before
N.B. : Malignant cystic lesions
-Biliary cystadenoma / carcinoma
-Cystic metastases

g) Hepatic Calcifications :
1-Multiple & small :
-Tuberculosis , histoplasmosis and less commonly
brucellosis
-Usually < 2 cm
2-Curvilinear :
-Hydatid
-Abscess
-Calcified (porcelain) GB

3-Localized in a mass :
-Metastases
-Fibrolamellar HCC
-Adenoma
4-Sunray spiculation :
-Hemangioma
-Metastases
-Adenoma
5-Diffuse increased density :
-Hemachromatosis

h) Hepatomegaly :
1-Neoplastic :
-Metastases
-Hepatoma
-Lymphoma
2-Rasied Venous Pressure :
-CHF
-Constrictive pericarditis
-Tricuspid stenosis
-BCS

3-Degenerative :
-Cirrhosis (especially alcoholic)
-Fatty infiltration
4-Myeloproliferaive Disorders :
-Polycythaemia rubra vera
-Myelofibrosis
5-Infective :
-Viral (hepatitis , IMN)
-Bacterial (abscess , brucellosis)
-Protozoal (amoebic abscess , malaria , trypanosomiasis &
kala-azar)

6-Storage Disease :
-Amyloid
-Hemochromatosis
-Gaucher’s Disease
-Niemann-Pick disease
7-Congenital :
-Riedel’s lobe
-Polycystic Disease

Diagnostic Imaging of the Liver

Diagnostic Imaging of the Liver

Recomendados

Recomendados

Mais conteúdo relacionado

Mais procurados

Mais procurados (20)

Semelhante a Diagnostic Imaging of the Liver

Semelhante a Diagnostic Imaging of the Liver (20)

Mais de Mohamed M.A. Zaitoun

Mais de Mohamed M.A. Zaitoun (20)

Último

Último (20)

Diagnostic Imaging of the Liver