[New diagnostic approaches in the assessment of the enlarged optic nerve--comparison of ultrasound echography and magnetic resonance tomography].

Enlargement of the orbital optic nerve was examined in patients by means of A- and B-scan ultrasonography and NMR imaging techniques; the results were then compared. We found that separation of the optical nerve sheets and the nerve structures themselves can be demonstrated with both methods, and increased width of the subarachnoidal space can be differentiated from the axonal cylinder. Our findings in meningeomas and gliomas are analyzed, as are the various reasons for edema of the disc. The pathogenesis of fluid collection in the subarachnoidal space in tumors of the optic nerve is discussed.