Arachnoid granulations in the transverse sinuses of a patient with ocular melanoma.

Arachnoid granulations show typical imaging features that allow their distinction from dural sinus thrombosis and intrasinus tumor. These features include a mid-lateral transverse sinus location, focality, common adjacent entering superficial veins, origin of attachment, low density on computed tomography (CT), isointensity-hypointensity on T1-weighted magnetic resonance imaging (MRI) and hyperintensity on T2-weighted MRI. We report the CT and MRI findings of incidentally detected bilateral arachnoid granulations in the transverse sinuses of a patient with ocular melanoma.