Noticable Findings in Cranial MRI of the Patients with Idiopathic Intracranial Hypertension

Idiopathic intracranial hypertension (IIH) is characterized by increased intracranial pressure. We investigated the optic nerve, Meckel's cavity, internal carotid artery (ICA) and pituitary findings of IIH by Cranial Magnetic Resonance Imaging (MRI).

Cranial MRI images of 35 adult patients with IIH and 35 adult subjects with normal cranial MRI results (control) were evaluated. Optic nerve diameter (OND), optic nerve sheat diameter (ONSD), OND/ONSD ratio, ON tortuosity, ON protrusion, posterior scleral flattening, ICA transverse diameter, CSF distance in Meckel's cavity and ICA transverse diameter/CSF distance in Meckel's cavity ratio, and pituitary gland measurements (height and transverse dimension; and Optic chiasm- pituitary gland distance) were measured.

OND and ONSD of the IIH group were significantly higher than those of the control groups at anterior and posterior measurements (p < 0.05). OND/ONSD ratio of the IIH group was lower at anterior measurement; and higher at the posterior measurement than the control group (p < 0.05). Right ICA transverse diameter and bilateral CSF distance in Meckel's cavity of the IIH group were higher than those of the control. Optic chiasm- pituitary gland distance of the IIH group was significantly higher than that of the control group (p < 0.05).

OND/ONSD ratio is different in anterior and posterior measurements. So we recommend measuring OND and ONSD separately in IIH patients to use in the clinical practice. Similarly, optic chiasm-pituitary gland distance is also another point to note for IIH patients on MRI. Our paper adds new approach to IIH in terms of OND/ONSD ratio.