Centrifugal (inside-out) enhancement of liver hemangiomas: a possible atypical appearance on contrast-enhanced US.

OBJECTIVE

To report the prevalence and to describe the atypical centrifugal (inside-out) appearance of contrast-enhancement of liver hemangiomas on contrast-enhanced sonography.

MATERIALS AND METHODS

Baseline and SonoVue-enhanced ultrasonography of 92 patients with 158 liver hemangiomas - considered atypical at grey-scale examination and confirmed by computed tomography, magnetic resonance imaging and ultrasound follow-up - were reviewed in consensus by two experienced radiologists, who evaluated baseline echogenicity and the dynamic enhancement pattern of each lesion looking for the presence of central enhancing foci in the arterial phase followed by a centrifugal (inside-out) enhancement in the portal-venous and late phases.

RESULTS

After administration of SonoVue, 12/158 hemangiomas (7.6%) (size range: 1-7cm; mean: 3.2cm) in seven patients (5 women, 2 men; age range: 34-71 years, mean: 50.8 years) showed a central enhancing focus in the arterial phase followed by a centrifugal enhancement in the portal-venous and late phases. In all cases centrifugal enhancement was incomplete at contrast-enhanced sonography, whereas computed tomography and/or magnetic resonance imaging were able to depict a complete and homogeneous fill-in.

CONCLUSION

Radiologist should be aware that centrifugal (inside-out) appearance on contrast-enhanced sonography is a rare but possible feature of liver hemangioma.