- At the discretion of the investigator, results from a historic imaging diagnostic, i.e. computer tomography (CT), digital volume tomography (DVT), or magnetic resonance tomography (MRT) (before screening and not older than 24 months, not taken during acute exacerbation), which will be considered additionally for confirmation of bilateral involvement of middle meatus and paranasal sinuses without resolution of symptoms (mucosal changes within the ostiomeatal complex and/or sinuses)