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

Abstract

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