MRI protocol and image analyses
Head MRI studies were performed on a 3.0 T system (Achieva X-Series, Philips Medical Systems, OH, USA) and T2-weighted images were used for the screening of paranasal sinusitis. All T2-weighted images were obtained in the axial plane, although, if necessary, sagittal or coronal images were also obtained. The images were analyzed independently by three observers, with more than 5 years of work experience in neuroradiology, who were unaware of the participants’ information or the study’s purpose.