Idiopathic ıntracranial hypertension: diagnostic contribution of novel MRI parameters and their relationship with CSF pressure.

backgroundIdiopathic intracranial hypertension (IIH) is associated with well-known classical neuroimaging hallmarks, but not all patients exhibit these typical findings. We aimed to investigate novel imaging features that could aid in diagnosing IIH and to assess the relationships between these features and cerebrospinal fluid (CSF) opening pressures.

methodsA total of 57 IIH patients (50 females, mean age 37 years) and 57 age- and sex-matched controls (mean age 34 years) were retrospectively evaluated. CSF opening pressures, brain MRI and MR venography findings were reviewed for typical IIH imaging features and novel basal cistern measurements, including Meckel cave dimensions, prepontine AP diameter, cerebellopontine cistern volume, mamillopontine distance, and pontomesencephalic/interpeduncular angles. Associations between imaging parameters and CSF opening pressure were analyzed.

resultsEmpty sella was the most frequent typical imaging finding, present in nearly all patients with IIH. Compared to controls, IIH patients showed increased prepontine AP diameter and larger Meckel cave measurements, while mamillopontine distance was reduced. Higher CSF opening pressure was associated with optic nerve sheath enlargement and/or bilateral transverse sinus stenosis. Mamillopontine distance demonstrated the best diagnostic performance (AUC: 0.710), with 66.7% sensitivity and 70.2% specificity at a 6.35 mm cut-off.

conclusionsIn addition to classical imaging findings, Meckel cave, prepontine AP diameter, and mamillopontine distance measurements differ significantly in patients with IIH from controls. High CSF opening pressure is associated with optic nerve sheath enlargement and bilateral transverse sinus stenosis.