Nasofrontal outflow tract visibility in computed tomography imaging of frontal sinus fractures

The choice of frontal sinus fracture treatment is based on multiple factors, one of which is injury to the nasofrontal outflow tract (NFOT). Computed tomography (CT) imaging of the NFOT can play an important role in the decision process. We sought to assess the visibility of the NFOT on CT scans in frontal sinus fractures. Patients with frontal sinus fractures (including the posterior table) receiving a CT scan from April 1st 2001 to December 31st 2009 were included. Scans were retrospectively assessed for available views (axial, coronal, and sagittal), slice thickness, inclusion of the anatomical NFOT region in the scanned area, and visibility of the NFOT. A total of 170 patients were included. In majority (71%) of patients NFOT was visible on one or more views, whereas in 33% (N = 56) of patients had three complete views (complete anatomical NFOT region scanned in three views). In this subgroup, the ability to assess the NFOT increased to 89%. When selecting patients with three complete views of ≤ 2 mm slice thickness (N = 47), the ability to assess the NFOT increased to 96%. In conclusion, when assessing the NFOT using CT imaging, having three complete views (axial, coronal, and sagittal) and a ≤ 2 mm slice thickness greatly increases the NFOT visibility.