パノラマ X 線撮影による上顎洞内隆起性病変の検出に関する実験的研究

Abstract

The radiographic examination of the maxillary sinus pathosis is usually accomplished by the Waters' projection, postero-anterior projection, and computed tomography. However, some lesions, such as the mucous retention cyst, post-operative maxillary cyst, and maxillary sinus carcinoma, as well as some lesions extending into the maxillary sinus, may be shown by panoramic radiography. In this study the detection of a globular radiopaque mass in the maxillary sinus of dry skull was compared experimentally using Waters' projection, postero-anterior projection, and panoramic radiography. Oil-clay masses with diameters of 5mm, 7mm, and 10mm were used as globular radiopaque masses, and they were always placed on the internal surface of the left maxillary sinus. The results obtained were as follows : 1. Globular radiopaque masses with diameters of 5mm, 7mm, and 10mm on the anterior wall of the maxillary sinus were detected in the sinus by every radiographic technique, but their correct positions were not clear. 2. Globular radiopaque masses with diameters of 5mm, 7mm, and 10mm on the posterior wall of the sinus were better shown by panoramic radiography. In panoramic radiography it was possible not only to detect a small radiopaque mass with a diameter of 3mm on the posterior wall, but also to determine its correct position in the sinus. 3. Globular radiopaque masses with diameters of 5mm, 7mm, and 10mm on the medial wall of the sinus were better shown by postero-anterior projection. But a globular radiopaque mass with a diameter of 3mm on the medial wall was not detected in the sinus. 4. Globular radiopaque masses with diameters of 5mm, 7mm, and 10mm on the floor of the sinus were better demonstrated by postero-anterior projection and panoramic radiography. In panoramic radiography, especially, it was possible not only to detect a globular radiopaque mass with a diameter of 5mm on the floor of the sinus, but also to determine its correct position on the floor of the sinus. A globular radiopaque mass with a diameter of 5mm on the floor of the sinus was also detected by postero-anterior projection, but its correct antero-posterior position on the floor was not clear. 5. Waters' projection is clinically utilized for the radiographic examination of the maxillary sinus pathosis. But it seems that Waters' projection is less effective for detection of globular radiopaque masses in the maxillary sinus. A radiopaque globular mass, especially on the floor of the maxillary sinus, is not clearly detected by Waters' projection, because of the overlapping of the maxillary molar teeth.