Imaging in the Work-Up of CSF Leak

In the diagnostic/pre-operative work-up of cerebrospinal fluid rhinorrhea imaging plays a key role. The localization of the site(s) of the leak is the most obvious main goal of the radiologic investigation, but there are several other critical issues that a proper imaging study can address. Two are the imaging techniques mainly indicated: computer tomography (CT) and magnetic resonance (MR). CT explores bony structures with fine detail, but it has low soft-tissue resolution. Conversely, MR can differentiate and characterize a wide range of soft tissues and fluids, allowing to directly visualize a CSF leakage. It is up to the radiologist to choose the imaging study (or the combination) most suitable for each specific situation. In fact, there is no standard study protocol that can fit all possible patients. Nevertheless, with just a few general indications in mind an informative exam can be obtained with relative ease. Performing a high-quality exam, though, is just the first part of the job for the radiologist. The next step is the analysis/interpretation of the images. To meet this target, the knowledge of the etiology of the rhinorrhea is of paramount importance, since different etiologies imply different reasoning for the correct interpretation of the radiological images.