[Immature hemangiomas in infants: MR and Doppler-US imaging features]

To determine the MR imaging features of immature hemangiomas. To discuss the value of MR imaging compared to Doppler ultrasonography (US).

We performed a retrospective study of clinical, Doppler US and MRI data of 12 immature hemangiomas in 11 children. The mean age was 2 months and 21 days. The mean clinical follow up was 22 months and 7 days.

MRI was performed for non-diagnosed lesions (4 cases) or to further define lesion extension (8 cases). The lesions either involved the head and neck (8 cases) or the extremities (4 cases). At MR imaging, all immature hemangiomas corresponded to well defined homogeneous T2W hyperintense masses. On T1-weighted images, 11 immature hemangiomas were isointense with intense homogeneous enhancement. Eleven tumors contained linear low signal intensity flow voids. Ten lesions had superficial cutaneous and/or subcutaneous extension whereas 2 lesions had intra-muscular extension. At Doppler US, immature hemangiomas were highly vascularized masses, with well defined margins, often compressibles, homogeneous isoechoic or heterogeneous with nodular hypoechoic foci, relative to subcutaneous fat. A diagnosis of immature hemangioma was confirmed either by pathology (2 cases) or clinical follow up (10 cases).

In our study, the MR imaging features of immature hemangiomas were reproducible and similar to reports from the literature. MRI is a useful tool to better define the extent of immature hemangiomas, which can be difficult to assess at US. The sensitivity and specificity of MR imaging for this pathology remain to be defined.