An analysis of the postoperative maxillary cyst using computed tomography

The diagnostic value of computed tomography (CT) as compared with conventional radiographs in the study of postoperative maxillary cysts (POMC) in 64 patients (85 sides) was evaluated. Typical CT findings of POMC were of a unilocular or multilocular homogeneous soft tissue density mass with expansile bony resorption. A comparison between conventional radiographs and CT proved that CT could determine the location and multilocularity of the cyst, the status of the antral walls, and abnormalities of the other paranasal sinuses and adjacent structures more precisely than conventional radiographs. CT also facilitated the ability to predict the direction of extension of the lesion. In conclusion CT was indispensable for accurately diagnosing POMC. In some cases the inferior extension of the lesion should be examined by conventional radiography because this can be obscured by degradation caused by metal artefacts during CT.