| Benign lesions |
| | Noncontrast ultrasound | Contrast-enhanced CT | Contrast-enhanced MRI |
| Hepatic hemangioma | - Well-demarcated homogeneous hyperechoic mass
- May be hypoechoic in patients with fatty infiltration of the liver due to the bright signal from the surrounding parenchyma
| - Well-demarcated hypodense mass on precontrast study
- Peripheral nodular enhancement in the early phase, followed by a centripetal pattern or "filling in" during the late phase
- Lesion usually opacifies after a delay of ≥3 minutes and remains isodense or hyperdense on delayed scans
| - Smooth, well-demarcated homogeneous lesion that has low-signal intensity on T1-weighted images and is hyperintense on T2-weighted images
- With contrast enhancement, early peripheral discontinuous nodular or globular enhancement is seen in the arterial phase with progressive centripetal enhancement or "filling-in" on delayed scans
|
| Focal nodular hyperplasia | - Variable appearance: May be homogenous hyper-, hypo-, or isoechoic lesion
- Central hyperechoic area (central scar)
| - Hypo- or isodense on noncontrast imaging with a central scar
- Hyperdense during the arterial phase
- Typically isodense during the portal venous phase, although the central scar may become hyperdense as contrast diffuses into the scar
| - An isointense lesion is noted on T1-weighted images, while an isointense to slightly hyperintense mass appears on T2-weighted images
- On delayed images, central scar appears hyperintense
|
| Hepatocellular adenoma | - Heterogenous, hyperechoic lesion in relation to the surrounding liver parenchyma
| - Typically well-demarcated lesion with peripheral enhancement during early phase with centripetal flow during portal venous phase
- Hepatocellular adenoma with recent hemorrhage appears as a high attenuating lesion
| - Typically a well-demarcated lesion with arterial phase enhancement
- Enhancement pattern in subsequent phases varies with lesion subtype
|
| Malignant lesions |
| | Noncontrast ultrasound | Contrast-enhanced CT | Contrast-enhanced MRI |
| Hepatocellular carcinoma | - Poorly-defined margins and coarse, irregular internal echoes
| - Hypervascular relative to the liver parenchyma during the arterial phase, with washout of the contrast during later phases
| - Lesion with low-intensity pattern on T1-weighted images and high-intensity pattern on T2-weighted images
|
| Intrahepatic cholangiocarcinoma | - Homogenous hypoechoic mass
| - Hypodense lesion with peripheral (rim) enhancement
| - Hypointense lesion on T1-weighted images and hyperintense lesion on T2-weighted images
- Dynamic images show peripheral rim enhancement followed by progressive and concentric filling-in of the tumor with contrast material
|
| Liver metastases | - Usually multiple lesions
- Metastases from adenocarcinoma are hypoechoic in comparison with the surrounding liver parenchyma
| - Metastatic liver lesions from the colon, stomach, and pancreas usually show lower attenuation (ie, are darker) in contrast to the brighter surrounding liver parenchyma
- Hypervascular metastases (eg, neuroendocrine tumor, renal cell carcinoma) appear as rapidly enhancing lesions visible on the arterial phase
| - Low-signal areas on T1-weighted images and moderately high-signal areas on T2-weighted images
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