Evaluation of optic nerve sheath complex by magnetic resonance imaging in patients with idiopathic normal pressure hydrocephalus

Background: We aimed to evaluate the optic nerve and optic nerve sheath diameter of patients with idiopathic normal pressure hydrocephalus with magnetic resonance imaging and to compare with the normal population. Methods: Magnetic resonance images and clinical records of the patients were retrospectively evaluated between 01.01.2015 and 01.01.2020. Twenty one patients in the normal pressure hydrocephalus group and 47 patients in the control group were included. Measurements were performed from the images obtained by creating multiplanar reconstructions from thin-slice Fast Spin Echo T2-weighted images. Measurements were made of optic nerve from the 3 mm posterior to the optic globe, on the plane which is oriented perpendicular to the nerve. Results: There was no difference between the two groups in terms of optic nerve diameters. Optic nerve sheath diameters are significantly higher in the normal pressure hydrocephalus group (p<0.0001). Conclusion: Morphological analysis of the optic nerve sheath complex which contains cerebrospinal fluid will contribute to the diagnosis and understanding chronic effects of normal pressure hydrocephalus, a disease in which changes in brain compliance and cerebrospinal fluid absorption are suspected in its etiology.