**10. Conclusion**

Imaging of sinonasal disorders shows a wide specter of diseases. However, the most common cause to unilateral CRS is odontogenic infection.

Odontogenic infection, pyocele, and fungal sinusitis are very often not in the list of the radiologist's differential diagnoses and often due to wrong CT imaging technique.

Sinonasal malignancy is rare but should always be in mind, especially in unilateral disease.
