US CT and MRI features of hepatic hemangiomas
US: Cavernous hemangiomas appear as well-defined hyperechoic masses in a normal liver. Doppler and color flow imaging usually demonstrate no detectable flow within the mass as blood flow is usually very slow; however, a feeding vessel may sometimes be detected. Occasionally hemangiomas have a mixed or hypoechoic appearance, especially in the setting of a fatty liver.
MDCT: On NCCT, hemangiomas are usually isodense to blood vessels, with 20% containing calcifications. A characteristic peripheral nodular enhancement pattern, isodense to the aorta, is present on HAP imaging; followed by slow central filling of the lesion, which becomes isodense to the blood pool in the PVP. The enhancement typically persists; however, large lesions may not completely enhance. Less frequently, hemangiomas may initially have central or uniform enhancement, similar to the pattern present in malignant lesions.
MRI: Hemangiomas are usually well defined and have decreased T1-w and increased T2-w signal compared with the normal liver. The signal increases on more heavily T2-w images equal to or greater than the signal of bile. Using dynamic contrast-enhanced MRI, the enhancement pattern is similar to the pattern on CT