Experimental explanation of maxillary sinus radiopacity as seen by Waters' and panoramic projections

The effect of radiographic imaging modalities and the observer's experience on postoperative maxillary cyst assessment

Purpose

The purpose of this study was to compare the accuracy of postoperative maxillary cyst (POMC) diagnosis by panoramic radiographs versus computed tomography (CT) and by oral and maxillofacial radiologists versus non-specialists.

Materials and Methods

Sixty-five maxillary sinuses with POMCs and 63 without any lesion were assessed using panoramic radiographs and CT images by five oral and maxillofacial radiologists and five non-specialists on a five-point scale. The areas under receiver operating characteristic (ROC) curves were analyzed to determine the differences in diagnostic accuracy between the two imaging modalities and between the two groups of observers. The intra-observer agreement was determined, too.

Results

The diagnostic accuracy of CT images was higher than that of panoramic radiographs in both groups of observers (p<0.05). The diagnostic accuracy of oral and maxillofacial radiologists for each method was higher than that of non-specialists (p<0.05).

Conclusion

The use of CT improves the diagnosis of POMC, and radiological training and experience leads to more accurate evaluation.

Experimental comparison of radiographic techniques in the detection of maxillary sinus disease

The radiographic examination of the maxillary sinus is usually accomplished by the Waters' projection. However, some lesions, such as the mucous retention cyst, postoperative maxillary cyst and maxillary sinus carcinoma, as well as some lesions extending into the maxillary sinus, may be shown by panoramic radiography. The present study was conducted to confirm the ability of panoramic radiography in the detection of maxillary sinus disease. The representation of a globular radiopaque mass at different locations in the maxillary sinus of a dry skull was compared in Waters' and panoramic projections. A mass with a diameter of 10 mm situated on the posterior wall or floor of the maxillary sinus was shown better by panoramic radiography. The Waters' projection was less effective; the mass, especially on the floor of the sinus, was not clearly demonstrated due to superimposition of the maxillary molar teeth.