Focal Liver Lesions MRI

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Focal liver lesions

MR imaging


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MRI TechniquesSequences

Coronal ultrafast spin-echo sequence(single breath-hold).

Axial fast spin-echo (T2-weighted)images.

Fat-saturated (frequency selective)

images increase the conspicuity ofliver lesions.

Axial 2D dual spoiled gradient-

recalled echo sequence (SPGR) (bothout-of- hase and in hase ima in


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Sequences

T1-weighted imaging

Diffusion-weighted imaging.

Dynamic contrast materialenhancedimaging at 20 (arterial phase), 60(portal venous phase), and 120

(equilibrium phase) seconds after theinjection of Gd-BOPTA and again at 1hour after injection


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Contrast agents

Extracellular fluid agents.

Hepatobiliary-specific agents.

Combined agents. Reticuloendothelial agents,

Blood-pool agents


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Hepatobiliary-specific Agents(Gd-BOPTA)

These hepatobiliary-specific agentsare taken up to varying degrees byfunctioning hepatocytes and are

excreted in the bile.

Gadolinium-based hepatobiliary-specific agents initially distribute in

the extracellular fluid compartment,just as extracellular fluid agents do,and are subsequently taken up by

hepatocytes.


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Focal liver lesions in MRI

Classification based on vascularizationpatterns

1.

Hypervascular lesions.2. Hypovascular lesions.

3. Lesions presenting delayed

persistent enhancement.


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Hypervascular lesions

Characterized by strong contrastenhancement in the arterial phasescan.

May be sharply demarcated or morediffuse appearance.


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Hemangioma

well-circumscribed mass of blood-filled spaces lined by endothelium ona thin fibrous stroma.

On T2-weighted images, they aremarkedly hyperintense and havecystlike signal intensity.

On T1-weighted images, hypointenserelative to the liver.

Three distinct enhancement patterns:


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Capillary Hemangioma


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Focal Nodular Hyperplasia

Represent a hyperplastic response ofthe hepatic parenchyma to apreexisting arterial malformation.

After hemangiomas, most incidentalhypervascular liver lesions innoncirrhotic livers represent FNH and

not adenoma. FNH - margin of the lesion, is

typically ill-defined or lobulated.

Adenomas - mar in is usuall smooth


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T1-weighted images - isointenserelative to the liver

T2-weighted images - isointense toslightly hyperintense.

Central scar is T1 hypointense and

T2 hyperintense.


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Hepatic Adenoma

Hepatic adenoma is a very rarebenign neoplasm.

Multiple in about 20% of cases,especially in patients with glycogenstorage disease.

Composed of benign hepatocytesthat are arranged in large plates orcords without acinar architecture.

T1-weighted images - variable signalintensit .


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Hepatic adenoma


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HepatocellularCarcinoma

Cirrhotic nodules range frombenign regenerative topremalignant dysplastic and frankly

malignant HCC. T1-weighted MR imaging, HCC

lesions less than 1.5 cm are often

isointense, whereas larger lesionsmay be hyperintense secondary tolipid, copper, or glycogen.

Fatty metamorphosis in a cirrhotic


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In cirrhotic patients, a hypervascularmass with increased T2 signal similarto that of the spleen is suspicious for

HCC. DWI - Well-differentiated tumors are

often isointense, whereas moderately

to poorly differentiated tumors aremore often hyperintense.

Arterial phase -heterogeneous

enhancement, portal venous and


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HypervascularMetastases

Hypovascular metastases showdecreased enhancement relative tonormal liver and are most

conspicuous on portal venous phaseimages.

Hypervascular metastases enhance

earlier, are best seen on arterialphase images, and show washout ondelayed images.

These metastases typically arise


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Hypervascular lesions -arterial phase


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Hypervascular lesions -arterial phase


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Hypovascular lesions


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Delayed persistentenhancement


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Focal Liver Lesions MRI

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