Solitary Liver LesionsA) Benign Tumours 1.Cavernous Haemangioma 2.Adenoma 3.Focal nodular hyperplasia 4.Mesenchymal Hamartoma

B)Infections 1. Abscess 2.Echinococcus cyst 3.Infective pseudotumour

C)Trauma 1.Haematoma 2.Traumatic cyst

D) Malignant Tumours 1.Hepatocellular carcinoma 2.Metastasis

E) Other 1.Fatty change 2.Simple cyst

CAVERNOUS HAEMANGIOMAMost common benign liver neoplasm.Usually in women, rare in children.Asymptomatic when small, mass effect when

large.May be isolated or multipleUsually in the posterior segment of the right

hepatic lobe. Usually less than 5 cm in diameter but can be

very large.

They typically remain stable in size but may demonstrate growth.

Rarely haemorrhage may occur.

Pathologically, composed of many endothelium-lined vascular spaces separated by fibrous septa.

Blood supply from the hepatic artery.

IMAGING FINDINGSUltrasound features

Well defined, rounded or ovoid hyperechoic lesion.

Homogeneous when small, heterogeneous due to internal haemorrhage and necrosis when large.

No/ minimal flow on color Doppler u/s.

IMAGING FINDINGSAt unenhanced CT, a well defined hypodense

lesion.

At contrast-enhanced CT, a characteristic pattern of enhancement.

Nodular peripheral puddling of contrast on

early-phase images, followed by centripetal diffusion into the centre.

Persistence of contrast on delayed images.

A central scar (if present) may not enhance, even on delayed images.

Calcification within hemangiomas has been reported.

Spiral CT,contrast enhanced,arterial phase.well defined rounded hypodense lesion with peripheral nodular puddling.

Spiral CT contrast enhanced, arterial phase, oval shaped hypodense lesion with peripheral nodular contrast enhancement.

Delayed phase, central perfusion of contrast with persistence of contrast.

MR imagingHemangiomas usually appear hypointense and well defined on T1-weighted images.

Demonstrate a marked hyperintensity that increases with echo time on T2-weighted images .

After administration of contrast, same characteristic pattern of enhancement as is seen at CT.

MRI T1W image, unenhanced, well defined rounded hypointense lesion in right lobe.

T1 post contrast

T1 post contrast,nodular puddling with central non enhancing scar

Focal nodular hyperplasiaSecond most common benign neoplasm of the

liver after hemangioma.

Typically occurs in young women

Asymptomatic, some may present with right upper quadrant pain.

Increased prevalence in women taking oral contraceptives .

Composed of hepatocytes, Kupffer cells, primitive bile ductules not connected with the biliary tree, and blood vessels .

A central fibrous scar containing a small arteriovenous malformation may be present.

Usually less than 5 cm in diameter , may be multiple and is often located near the liver surface.

IMAGING FEATURESUltrasound findings

Well defined mass of hypo, iso or hyperechogenicity.

Doppler U/S demonstrates high velocity flow within the lesion.

At unenhanced CT, appears homogeneous, well defined, and

hypo to isodense relative to the liver.

At contrast-enhanced CT, it exhibits a characteristic pattern of enhancement.

Enhances brightly on early-phase images with subsequent wash out.

On delayed scans, the mass may be isodense relative to the liver and therefore imperceptible except for any mass effect.

A central scar (if present) may demonstrate delayed enhancement and may remain bright on subsequent images due to delayed washout .

Contrast enhanced spiral CT arterial phase, well defined heterogeneously enhancing oval lesion in left lobe with central non enhancing scar.

Arterial phase contrast enhanced spiral CT,isodense lesion displacing adjacent vessels, central non enhancing scar

Delayed scan, imperceptible lesion, persistantly enhancing central scar.

At MR imaging, Iso to hypointense on T1-weighted images and hyperintense on T2-weighted images.

Demonstrates early arterial enhancement after administration of contrast with rapid wash out.

However, the central scar shows delayed enhancement with delayed wash out.

T1W MRI, axial cuts, contrast enhanced,arterial phase showing an oval shaped brightly enhancing lesion in left lobe.

Delayed phase, lesion becoming isointense to normal liver

Hepatic abscessLocalized collections of necrotic

inflammatory tissue caused by bacterial, parasitic or fungal agents

In developing countries, parasitic abscesses are most common, including

amoebaeechinococcusprotozoahelminths

In developed countries, bacterial abscesses are most common, usually in association with a co-morbidity such as:

Abdominal sepsisImmunocompromised

Diabetes mellitus HIV/AIDSElderlyChemotherapy / transplant recipientsMalignancy

TraumaERCPCryptogenic

Most common bacterial agents are Gram negative and gram positive organisms

Escherichia coli,Klebsiella pneumoniae,bacteroides

anaerobic streptococci,enterococciTypical presentation is of right upper

quadrant pain, fever and jaundice. Anorexia, malaise and weight loss are also

frequently seen.

RADIOGRAPHIC FEATURESAs a general rule, bacterial and fungal abscesses

are often multiple, whereas amoebic abscesses are more frequently single.

Amoebic abscesses are more common in a sub-diaphragmatic location

Are more likely to spread through the diaphragm and into the chest. 

Amoebic abscess is more likely to be round or ovoid, hyporeflective with fine level echoes.

Ultrasound FindingsPyogenic abscesses are typically poorly

demarcated with a variable appearance, ranging from predominantly hypoechoic to hyperechoic.

Hyporeflective and irregular wall.

Internal contents may show debris, fluid levels and septations.

Gas bubbles may also be present.

Doppler will demonstrate absence of flow.

Amoebic abscesses are typically single

Peripherally located

Well defined round or ovoid mass

With fine low level internal echoes.

CT Scan Variable in appearance.

In general, appears as peripherally enhancing, centrally low density lesion.

Occasionally they appear solid, or contain gas. 

Oval shaped hypodense lesion with peripherally enhancing irregular rim.

MRIT1

HeterogeneousUsually hypointense centrallyMay be slightly hyperintense in fugal abscessEnhancement of the capsule, although this may

be absent in immunocompromised patientsMultiple septations may be present

T2 - tends to have hyperintense signal.

Hydatid cystHydatid disease is a worldwide zoonosis

produced by the larval stage of the Echinococcus tapeworm

The two main types of hydatid disease are caused by E granulosus and E multilocularis.

Definitive host is dog.

Human becomes the intermediate host when comes in contact with definitive host.

The right lobe is the most frequently involved

Imaging findings depend on the stage of cyst growth

whether the cyst is unilocularcontains daughter cystsis partially calcified,or is completely calcified [dead]

Ultrasound findings

US is the most sensitive modality for the detection of membranes, septa, and hydatid sand within the cyst.

Simple cyst appears as well defined anechoic lesion with posterior acoustic enhancement.

Echogenic foci due to hydatid sand may be seen within the lesion by repositioning the patient.

Quickly fall to the most dependent part of the cavity without forming visible strata—snow storm sign.

Detachment of the endocyst from the pericyst-- “floating membranes”.

Complete detachment of the membranes inside the cyst-water lily sign.

Multivesicular cysts manifest as well-defined fluid collections in a honeycomb pattern with multiple septa.

Membranes may appear within the matrix as serpentine linear structures.

Calcification seen in 20%–30% of cases.

Usually manifests with a curvilinear or ringlike pattern.

Or dense calcification of all components during healing phase.

Zoomed imaged, well defined oval shaped heterogeneous lesion with internal echoes.Internal echogenic serpentine structures—collapased membranes.

CT Scan findings

Indicated when U/S fails due to: Patient-related difficulties (e.g, obesity,

excessive intestinal gas, abdominal wall deformities, previous surgery) or

Disease complications.

CT may display the same findings as U/S.

Cyst fluid usually demonstrates water attenuation (3–30 HU).

Calcification of the cyst wall or internal septa is easily detected at CT.

Typically has a high-attenuation wall at

unenhanced CT even without calcification.

Detachment of the membranes is visualized as linear areas of increased attenuation within the cyst.

Hydatid cyst with collapsed parasitic membranes. Unenhanced CT scan shows a circular area of increased attenuation within the cyst representing detached membranes

MRI FindingsA well defined hypointense lesion on T 1 and

hyperintense on T2 W images.

A characteristic sign of hydatid disease is a low-signal-intensity rim on T2-weighted images, represents the collagen rich outer layer of the hydatid cyst.

Collapsed parasitic membranes appear as twisted linear structures within the cyst.

Noncalcified hydatid cysts. Axial T1-W MRI.two large cystic lesions in the right hepatic lobe. Anterior cyst has high SI(reduction in the water content of the fluid).Several round,nodular,low SI lesions--daughter cysts.Mother cyst has a characteristic low SI rim. Posterior cyst has homogeneous low SI with a double ring.hypointense outer ring– pericyst,partially “wrinkled,” intermediate SI inner ring--incompletely detached membranes

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