CT and MRI features of a hepatic hemangioma
What are the CT and MR imaging features of a hepatic hemangioma?
Hepatic hemangioma is the most common benign hepatic neoplasm, and it is composed of vascular channels and fibrous stroma. On CT, hepatic hemangioma appears as a well-defined lobulated low attenuation lesion. On MRI, it is hypointense on T1-weighted images and hyperintense on T2-weighted images relative to liver parenchyma. On heavily T2-weighted images, it remains hyperintense relative to liver parenchyma and spleen, although with signal intensity less than simple fluid.
Peripheral nodular discontinuous enhancement (following the enhancement of the aorta) with subsequent centripetal fill-in and persistent delayed phase enhancement is the characteristic enhancement pattern of hepatic hemangioma, and it is pathognomonic of this diagnosis. Small hemangiomas (<1.5 cm) may sometimes demonstrate homogeneous arterial phase (“flash filling”) enhancement, potentially mimicking hypervascular hepatic malignancies. However, hemangiomas will have persistent hyperenhancement in the venous and delayed phases of enhancement relative to liver parenchyma, whereas malignant lesions will tend to become isoenhancing or hypoenhancing relative to liver parenchyma in the venous or delayed phases of enhancement. Large hemangiomas (>4 to 5 cm) almost always have a central cleft-like area of cystic degeneration or liquefaction that has low attenuation, low T1-weighted signal intensity, and very high T2-weighted signal intensity, without enhancement.