The purpose of this study was to evaluate the usefulness of adding Waters' projection to panoramic imaging compared with panoramic imaging or Waters' projection alone. Maxillary sinusitis in 106 patients (206 sinuses) was retrospectively assessed with panoramic imaging, Waters' projection, and computed tomography imaging by two oral radiologists. The diagnostic performance was assessed with computed tomography imaging as the gold standard. Receiver operating characteristic curves and area under the curve values were obtained. Inter- and intra-observer agreement was quantified using weighted kappa coefficients. Observer A performed the same procedure twice (A1 and A2 for the first and second observations, respectively). The accuracies of observers A1, B, and A2 with combination imaging were 0.699, 0.636, and 0.718, respectively. Their area under the curve values with combination imaging were 0.746, 0.640, and 0.771, respectively. Inter-observer agreement was good for Waters' projection (κ, 0.650), and poor for panoramic imaging (κ, 0281). Intra-observer agreement was good for Waters' projection (κ, 0.752), and moderate for panoramic imaging (κ, 0.597). Panoramic imaging was equivalent to Waters' projection for diagnosing maxillary sinusitis. Combination imaging comprising panoramic imaging and Waters' projection can contribute to the diagnosis of odontogenic maxillary sinusitis because of its high sensitivity.
Keywords: Computed tomography; Maxillary sinusitis; Panoramic imaging; Waters' projection.