Optic tract edema: a highly specific magnetic resonance imaging finding for the diagnosis of craniopharyngiomas.

Objective: To clarify the accuracy, sensitivity, and specificity of optic tract edema in the diagnosis of craniopharyngiomas.

Methods: Preoperative magnetic resonance images (MRIs) of 49 patients (between May 1996 and March 2003) who had a diagnosis of parasellar masses were blindly reviewed by two radiologists. The spread of edema surrounding the tumor on the coronal TSE T2-weighted images was analyzed. Sensitivity and specificity were calculated based on the numbers in this series and also pooled numbers from previous known reported series.

Results: Edema along the optic tracts was detected in 7 of 11 craniopharyngiomas, giving a sensitivity of 63.6% (95% CI = 30.8-89.1) for our series and 66.7% (95% CI = 47.2-82.7) for the pooled numbers. The specificity was 100% (95% CI = 90.7-100.0) for our series and 93.9% (95% CI = 87.1-97.7) for the pooled numbers. None of the 28 pituitary macroadenomas, 4 meningiomas, 2 hypothalamic astrocytomas, 2 germinomas, 1 mixed-germ cell tumor and 1 arachnoid cyst in our study showed edema of the optic pathways.

Conclusions: Optic tract edema, commonly seen in craniopharyngiomas, is a useful MR finding for distinguishing craniopharyngiomas from other parasellar tumors with considerable sensitivity and high specificity.