Optic Sheath Meningioma

Clinical History: 
This 54 year old female patient presented with subtle, progressive, partial loss of sight involving the left eye. Clinical exam showed papilledema and atrophy of the optic nerve on the left.

Optic nerve sheath meningioma.

MR Technique: 
All images were acquired on a 1.5 T whole body MR System (Magnetom Avanto, Siemens Medical Solutions, Erlangen, Germany) using a 12 element standard head coil. T1-weighted images were acquired with fat saturation after administration of a gadolinium chelate in both the coronal and axial planes. Sequence details are: TR/TE = 647/17, 1:48 min acquisition time, bandwidth 130 Hz/pixel, 168×320 matrix and 1.0 x 0.7 x 3.0 mm3 spatial resolution. T2-weighted images were acquired before contrast agent administration in the axial plane with TR/TE = 1500/132, requiring 5:24 min for acquisition. Bandwidth was 410 Hz/pixel, matrix 268 x 320, and spatial resolution 0.9 x 0.8 x 1.0 mm3.


fig. A


fig. C


fig. D

 Imaging Findings:
The optic nerve and tumor are isointense on the T1- and T2-weighted sequences prior to contrast administration (A, C). After contrast administration the optic nerve remains hypo-/iso-intense in distinction to the hyperintense (enhancing) tumor (B, D). This leads to the typical “tram track sign” caused by the contrast agent uptake of the tumor surrounding the non-enhancing optic nerve (D).