Background: Pituitary macroadenoma with optic nerve or optic chiasm compression may lead to further visual impairment and need surgical treatment.
Objective: We aim to evaluate microstructural change of the optic radiation in pituitary macroadenoma patients before surgery compared to the normal control subjects by diffusion tensor imaging (DTI).
Material and Method: Nine patients with pituitary macroadenoma and optic chiasm compression confirmed by 3-Tesla MRI (pituitary protocol) and 9 normal control subjects were evaluated with DTI. The probabilistic tractography and DTI
parameters of optic radiation were evaluated in both patients and normal control subjects.
Results: There were statistically significant increase of radial diffusivity (RD, p<0.05), 2nd and 3rd eigen values (p<0.05) in
pituitary macroadenoma patients whereas, slightly increased in mean diffusivity (MD) and decreased in fractional anisotropy (FA) of the patients but no statistically significant difference (p = 0.053 and 0.133, respectively) as compared with normal
control subjects.
Conclusion: Microstructural change of the optic radiations in pituitary macroadenoma patients with optic chiasm compression
was demonstrated by means of DTI parameters before conventional MRI. Therefore, the value of DTI parameters might be non-invasive tools for further evaluation and prediction of visual recovery after surgery as correlate with clinical examination.

Keywords: Pituitary macroadenoma, Diffusion tractography, DTI, Optic radiation