[MRI findings of orbital hemangiomas]

To evaluate the MR imaging findings of orbital hemangiomas in pediatric and adult groups.

MR imaging findings of seven orbital hemangiomas were reviewed. All patients had axial and coronal T1 and T2 weighted images. Axial and coronal fat suppressed (STIR) images and postcontrast T1 weighted images in three planes were obtained in order to evaluate the relation with surrounding structures. Localization, size, margins and signal characteristics of the lesions were analyzed.

Four of the cavernous hemangiomas were intraconal, one was extraconal. The location of the lesions was superomedial in two, middle medial, inferomedial and inferolateral in one lesion. The lesions were iso-hypointense to muscle on T1W, hyperintense on T2W and markedly hyperintense on STIR images. All cases had a capsule. In four cases a chemical shift artifact was seen. Contrast enhancement was patchy in early images and homogenous in late images. Cavernous hemangiomas were well circumscribed. All cases underwent operation and had a histopathologic diagnosis. The capillary hemangioma seen in a ten-year-old case was superomedial in localization and had irregular contours. The other case was a one year old. The lesion surrounded the superolateral margin of the bulbus and involved the lateral rectus, the eyelid and neighboring skin. The lesions were hypointense on T1W and hyperintense on T2W images, with diffuse homogenous contrast enhancement.

With MRI, orbital hemangiomas, the most common cause of chemosis and proptosis are easily detected. MR findings are not only helpful for diagnosing the lesion but also for choosing the appropriate surgical approach.