Non-invasive aspergillosis of the paranasal sinuses: CT and MRI findings

Aspergillosis is the most common fungal infection of the paranasal sinuses, and needs to be recognized because it requires surgical removal. Twenty proven cases of aspergillosis of the paranasal sinuses are reported here. CT was performed in all the cases and MRI in 2 cases. The maxillary sinus was affected in 19 patients and the sphenoid sinus in 1. Mycosis was unilateral in all but 1 of the cases. Foci of increased attenuation at CT were observed in 18 cases, with calcification in 10 cases and/or dental material in 13 cases. An increased bony wall thickness was observed in 16 cases. All the patients but 1 had at least one of the signs. At MRI the fungal mass displayed a hypointense signal on T1- and T2-weighted images. No enhancement was noted on post-contrast T1-weighted images. The diagnosis of paranasal sinus aspergillosis is suggested by the CT findings, when a hyperdense mass with calcifications and/or dental material is noted with thickening of the sinus wall. MRI may have a complementary diagnostic role in doubtful cases.