Idiopathic intracranial hypertension (IIH) is characterized by elevated intracranial pressure of unknown cause, resulting in typical symptoms such as headache and impairment of the optic nerve due to papilledema. It is rare in the general population but disproportionately affects women of childbearing age with obesity (20 cases per 100 000 population).
1-3 Currently, the diagnosis of IIH is based on expert opinion, as summarized in the 2013 diagnostic criteria,
4 and requires (1) normal neurological examination findings except abducens nerve palsy, (2) normal magnetic resonance imaging (MRI) brain parenchymal and cerebral venography findings, (3) normal cerebrospinal fluid (CSF) composition, (4) elevated lumbar puncture opening pressure (≥25 cm H
2O in adults), and (5) papilledema. However, when papilledema is absent but conditions 1 to 4 are fulfilled, patients are classified as having IIH without papilledema when presenting with abducens nerve palsy or as having suspected IIH without papilledema when presenting with 3 of 4 MRI criteria (empty sella, flattening of the posterior aspect of the globe, distension of the perioptic subarachnoid space with or without a tortuous optic nerve, and transverse venous sinus stenosis
4) instead. However, the diagnostic impact of these MRI criteria is vague, because they are neither evidence based nor further specified, resulting in variable interpretation and application; furthermore, they are often difficult to assess with standard MRI examination and require specific thin-slice orbital or pituitary gland sequences. Because of these pitfalls, up to 40% of patients examined outside tertiary centers receive an incorrect diagnosis.
5-8 An evidence-based update of the 2013 diagnostic criteria, in which IIH is defined by the presence of 2 of 3 findings (papilledema, opening pressure ≥25 cm H
2O, and ≥3 neuroimaging signs), has been suggested recently.
9 With this update, abducens nerve palsy was removed from the criteria, and empty sella was replaced by suprasellar CSF herniation into more than one-third of the sella turcica.
9 In addition, an increasingly large panel of neuroimaging signs associated with IIH has been proposed, although its use has yielded contradictory results, and these signs have not been validated in a prospective, clinical practice patient cohort.
10-14 Here, we blindly evaluated a comprehensive panel of neuroimaging signs for IIH diagnosis in a well-defined, meticulously characterized population of patients with clinically suspected IIH and validated our results internally in parts of our patient cohort, as well as externally in patient cohorts from other university hospitals.