Computed tomography attenuation measurements for the characterization of hepatic haemangiomas.

The attenuation values of 21 hepatic haemangiomas in 19 patients were measured on non-enhanced computed tomographic (CT) scans and compared with the attenuation of adjacent liver and the inferior vena cava (IVC). The attenuation of hepatic haemangiomas was lower than that of the surrounding liver, but there was no correlation between these two measurements. There was a highly significant correlation between the attenuation of haemangiomas and blood in the vena cava (r = 0.905, p less than 0.001). All the haemangiomas had attenuations within 7 HU of caval blood. By comparison, in 34 hypodense hepatic lesions that did not show contrast-enhanced appearances characteristic of haemangioma, there was no significant correlation between the attenuation of the lesions and the IVC. Nineteen (56%) of these lesions had attenuations differing more than 7 HU from that of caval blood. The influence of this observation on the requirement for dynamic contrast-medium-enhanced and delayed post-contrast CT in the assessment of hepatic lesions is discussed.