Value of systematic analysis of the olfactory cleft in case of cerebrospinal rhinorrhea: incidence of olfactory arachnoid dilatation.

To report on the presence of olfactory arachnoid dilatations (OAD), a previously undescribed radiologic feature of spontaneous cerebrospinal fluid (CSF) rhinorrhea originating from the cribriform plate of the ethmoid bone. The medical records of all patients treated between 2001 and 2011 at a tertiary care center for a spontaneous CSF rhinorrhea originating from the cribriform plate were retrospectively reviewed. The radiological work-up included high-resolution computed tomography and magnetic resonance imaging with at least the following sequences: T1, T2, and T2 with fast imaging employing steady state acquisition (FIESTA).