Optic chiasmal edema observed on T2-weighted MR images: a reversible finding in obstructive hydrocephalus.

PURPOSE

To evaluate the clinical significance of optic chiasmal edema (OCE) observed in hydrocephalus.

MATERIALS AND METHODS

Twenty patients with obstructive hydrocephalus and eight patients with communicating hydrocephalus were recruited. We classified both groups into OCE-positive and negative subgroups on three-dimensional T2-weighted images. In the obstructive hydrocephalus group, the pre- and postoperative periventricular hyperintensity (PVH) grade, Evans index, and third ventricle diameter were compared between the subgroups. The visual disturbances were reviewed in the medical records.

RESULTS

Eleven obstructive hydrocephalus patients (55 %) had OCE, while none of communicating hydrocephalus patients did. OCE was improved in all patients postoperatively. Preoperative PVH grade was significantly higher in the OCE-positive subgroup (p < 0.01). There were no statistically significant differences in the other indices. Visual disturbances were observed in two OCE-negative patients alone.

CONCLUSION

OCE is a reversible finding frequently observed in obstructive hydrocephalus and may not be associated with visual disturbances.