Imaging investigations of optic gliomas

Abstract

Objective To evaluate CT and MR imaging findings of optic gliomas and their clinical significance.Methods CT and MR imaging findings of 20 patients with pathologically confirmed optic gliomas were analyzed retrospectively.The age of the patients ranged from 8 months to 69 years.Ten patients were female and ten were male.CT scanning was performed in 10 patients with contrast scanning in 2,and MR imaging was performed in 19 patients with contrast scanning in 14.Results Of the 20 cases with optic gliomas,a fusiform thickening of the optic nerve was found on CT and /or MR imaging in 12,a tubular enlarging and kinking of the optic nerve in 5,a dumb-bell mass of the optic nerve in 2,and an ovoid mass in 1.Enlargement of intraorbital and intracanalicular segments of the optic nerve was seen in all 20 cases,simultaneous enlargement of intracranial segment in 15,a simultaneous mass of intraocular segment in 4,a simultaneous mass of optic chiasm in 6,and simultaneous enlargement of optic tract in 2.CT scanning performed in 10 patients showed iso-density mass.Enhancement of enlarged optic nerve was observed on postcontrast CT in two.MR imaging performed in 19 patients displayed a long T_1 and long T_2 signal intensity mass in 12,a long T_1 and identical T_2 signal intensity mass in 5,and an isointense mass on T_1- and T_2-weighted images in 2.After contrast administration in 14 cases,marked enhancement of the mass was seen in 12 cases,and moderate enhancement was demonstrated in 2.Of the 7 patients associated with neurofibromatosis Ⅰ,four optic gliomas appeared as a specific sign─ isointense in the center on both T_1- and T_2-weighted images,hypointense on T_1- and T_2-weighted images in the intermediate portion,and long T_1 and long T_2 signal intensity in peripheral portion.After statistical analysis,MR imaging was superior to CT in demonstrating the tumor involvement of the intracanalicular and intracranial segments of the optic nerve (P0.01). Conclusion CT and MR imaging could demonstrate the site,configuration,and characteristics of the tumors and may contribute to the diagnosis and treatment.MR imaging was superior to CT in the diagnosis of optic gliomas.