Incidental Findings in Paranasal Sinuses and Mastoid Cells: A Cross-Sectional Magnetic Resonance Imaging (MRI) Study in a Pediatric Radiology Department

Purpose: Misdiagnosis of "sinusitis" is still frequent in children, although mucosal swelling in the paranasal sinuses of children has been reported as a common incidental finding. Recent radiological publications on the problem are rare. We prospectively evaluated the mucosal thickening in the paranasal sinuses and mastoid cells of children who underwent MRI of the head for reasons other than sinusitis or mastoiditis. Materials and Methods: 147 patients, 0.2 - 22.7 years, median 8.9. Axial and sagittal 12 TSE images were evaluated by two experienced pediatric radiologists. Categories for the degree of mucosal swelling were for the maxillary, frontal and sphenoid sinuses: no swelling, minor: < 5 mm, or major: >= 5 mm; for ethmoid cells and mastoid cells: not present, minor: <= 50% of cells, or major: > 50 %. Results: 61 % of children had one or more salient findings in their paranasal sinuses or mastoid cells. 48% had mucosal swelling in their paranasal cavities, 25% in their mastoid cells. The prevalence was higher among children less than 10 years of age (60% and 42%) and among children with current upper respiratory tract infection (71% and 35%). There was no correlation to a history of headache, snoring, asthma and allergies, or to gender or place of residence. Conclusion: Mucosal swelling in paranasal sinuses and in mastoid cells is a frequent incidental finding in children. Even major mucosal swelling in a paranasal sinus is not necessarily a sign of infection. In radiological reports the terms "sinusitis" and "mastoiditis" should therefore be used with great caution. The initiation of treatment should be based on clinical symptoms and not on radiological abnormalities alone.