Complementary role of MR imaging of ethmomaxillary sinus disease depicted at CT in cystic fibrosis.

Purpose: To assess whether MR imaging can improve characterization of ethmomaxillary opacification diagnosed at CT in patients with cystic fibrosis (CF) in order to select patients that may benefit from functional endoscopic sinus surgery (FESS).

Material And Methods: Sixty-two CF patients (26 females and 36 males) aged 4-50 years (median 20 years) with ethmomaxillary sinus disease at CT underwent MR examination of the paranasal sinuses (coronal T1 and STIR sequences). FESS had been performed in 28 of the patients prior to this study. MR signal intensities were interpreted as mucosal thickening or infectious material, according to a previous study.

Results: Three major maxillary sinus MR patterns could be distinguished: Air-filled, oval-shaped pus-filled, and streaky-shaped pus-filled sinus lumen. For air-filled maxillary sinuses with mucosal thickening, CT and MR imaging were diagnostically equivalent. Where CT showed homogeneous opacification of the maxillary sinuses, MR imaging differentiated between thickened mucosa and pus-filled areas. Patients who had undergone FESS most commonly had air-filled or streaky-shaped pus-filled maxillary sinus lumen. In non-operated patients oval-shaped pus-filled sinus lumen was most common and could occur without ethmoid disease.

Conclusion: MR imaging of the paranasal sinuses can differentiate between infectious material and thickened mucosa and should be used to select CF patients with pus-filled areas that can be eradicated with FESS.