[State of the Art. Diagnostic imaging of paranasal sinus diseases].

The following article describes a diagnostic concept of paranasal sinus imaging, based on more than 10 years close collaboration of the authors. CT and MR are the primary imaging modalities for investigating paranasal sinus lesions. Conventional X-ray images add little information due to insufficient sensitivity. Angiography is restricted to those patients who require preoperative tumor embolization or emergency treatment of intractable epistaxis. After thorough medical treatment of inflammatory paranasal sinus disease, CT becomes the method of choice to clearly depict preoperative osseous anatomy and to distinguish between benign and malignant intraosseous lesions. In cases where trauma is involved, CT easily identifies anterior skull base fractures. Moreover, CT will be the first step to localize early or late CSF rhinorrhea. MR, with its ability to distinguish between different soft tissues, compliments CT. This holds particularly true for inflammatory or neoplastic disease close to the skull base, orbital apex and cavernous sinus. The signal intensity in T(1) and T(2) weighted images provides additional information with respect to cellularity and vascularization of lesions, which has important diagnostic and therapeutic implications.