Delineation of Optic Nerves and Chiasm in Close Proximity to Large Suprasellar Tumors with Contrast-enhanced FIESTA MR Imaging

Abstract

To evaluate whether contrast material-enhanced (CE) fast imaging employing steady-state acquisition (FIESTA) can depict the anterior optic pathways in patients with large suprasellar tumors. Institutional review board approval was obtained. Twenty-eight patients with large suprasellar tumors undergoing surgical treatment (19 pituitary adenomas, six meningiomas, and three additional miscellaneous tumors) underwent preoperative magnetic resonance (MR) imaging, including CE FIESTA, at 3.0 T. Two radiologists assessed the visibility of five segments of the optic pathways (bilateral optic nerves and optic tracts, optic chiasm) with CE FIESTA and conventional MR imaging, including thin-section coronal T2-weighted imaging and CE T1-weighted imaging, by using a three-point scale. Moreover, the preoperative signal intensity of the optic pathways was correlated with pre- and postoperative visual impairment to determine whether high signal intensity at CE FIESTA is predictive of persistence of visual impairment after surgery. The χ(2) test was used to compare scores assigned to CE FIESTA and conventional MR images. The percentage of anterior optic pathways rated as visible was significantly higher with CE FIESTA than with conventional MR imaging (100% [140 of 140 segments] vs 78% [109 of 140 segments], P < .05). Thirty-one of the 140 segments (22%) were not depicted with conventional MR imaging; all of these 31 segments were visualized with CE FIESTA. For 12 patients who underwent transcranial surgery, the anatomic locations of the optic pathways at CE FIESTA were compatible with the surgical findings. CE FIESTA helped predict persistent visual impairment after surgical treatment with a sensitivity of 75% (three of four patients) and a specificity of 96% (23 of 24 patients). The accuracy of CT FIESTA in the prediction of visual loss was significantly higher than that of T2-weighted imaging (93% [26 of 28 patients] vs 50% [14 of 28 patients], P < .05). CE FIESTA is useful for the preoperative localization of the anterior optic pathways in patients with large suprasellar tumors and offers the potential to predict persistent visual impairment after decompression.