Imaging features and management of focal liver lesions

Table 3 Imaging features of common liver lesions

	US	CT (non-contrast)	MRI	Enhancement pattern (CT and MRI)
Hepatic hemangioma	Hyperechoic	Hypodense well-defined homogeneous lesion	T1: Hypointense	Arterial phase: Discontinuous, peripheral, nodular
	Well-defined homogeneous		T2: Markedly hyperintense	Enhancement
	lesions with acoustic enhancement			Portal venous and delayed phases: Progressive
	Rarely hypoechoic due to hepatic steatosis			Centripetal filling
				Hepatobiliary phase: Pseudo washout
Focal nodular hyperplasia	Difficult to detect (stealth lesion)	Difficult to detect (stealth lesion)	T1: Homogeneous isointense to slightly hypointense with hypointense stellate central scar	Arterial phase: Intense, homogenous enhancement
				Portal venous and delayed phases: Isointense or slightly hyperintense to the liver parenchyma
	Variable echogenicity	Hypodense or isodense well-defined lesions
			T2: Isointense to slightly hyperintense
			± Hyperintense central scar
				Hepatobiliary phase: Isointense or slightly hyperintense to the liver parenchyma
				± Central scar: Enhanced with extracellular gadolinium contrast agents, but not enhanced with HSCA
Hepatocellular adenoma	Heterogenous, well-defined lesions	Well-defined heterogenous lesion	T1: Variable signal intensity loss of signal	Arterial phase: Intense enhancement
	Highly variable echogenicity	± Hyperdense if hemorrhagic
		± Hypodense if fatty	On opposed-phase if fatty
		± Calcification in areas of old hemorrhage	T2: Hyperintense
Hepatic cyst	Anechoic, well-defined, homogenous lesion	Well-defined homogenous, hypodense lesion	T1: Hypointense	No enhancement with contrast agents
			T2: Hyperintense
			Well-defined, homogenous lesion
Polycystic liver disease	Multiple cysts with features, resembling hepatic cysts US findings	Multiple cysts with features, resembling hepatic cysts CT findings	Multiple cysts with features, resembling hepatic cysts MRI findings	No enhancement with contrast agents
Mucinous cystic neoplasm of liver	Solitary, well-defined, multiloculated anechoic lesion with septations	Well defined heterogenous lesion	T1: Variable signal intensity	± Enhancement of wall/septations
		± Calcification	T2: Hyperintense
	± Septal/mural nodules
	± Calcification
Cholangiocarcinoma	Heterogenous	Heterogenous hypodense lesion with capsular retraction and parenchymal atrophy	T1: Heterogeneous hypointense	Arterial phase: Peripheral, enhancement (targetoid appearance)
	Variable echogenicity
	± Hypoechoic rim		T2: Peripherally hyperintense and centrally hypointensite	Portal venous and delayed phases: Progressive, persistent heterogeneous enhancement
	± Dilated intrahepatic bile ducts	± Dilated intrahepatic bile ducts
	± Satellite lesions	± Satellite lesions
		± Vascular encasement
Hepatocellular carcinoma	Variable echogenicity	Early HCC, isodense, ± hypodense if fatty	T1: Variable signal intensity, ± loss of signal	Arterial enhancement
				Portal venous, delayed and hepatobiliary phases: Washout
		Progressed HCC, isodense or hypodense, occasionally hyperdense	On opposed-phase if fatty
			T2: Variable signal intensity, typically moderately hyperintense

CT: Computed tomography; MRI: Magnetic resonance imaging; US: Ultrasound; HSCA: Hepatobiliary-specific contrast agents.