上顎洞後壁部骨欠損の検出に関する実験的研究 : パノラマ X 線撮影と X 線 CT の比較

Abstract

An experimental comparison in the detection of bony defects in the maxillary sinus posterior wall and the zygomatico-alveolar region of dry human skulls was made using panoramic radiography and computed tomography (CT). Locations in the posterior wall where the bony defects were experimentally created were in the center, facing the pterygopalatine fossa, above the maxillary tuberosity, and adjacent to the zygomatic process of the posterior wall of the maxillary sinus. Also, defect was created in the zygomatico-alveolar region of the maxilla. In this study, bony defects with diameters of 5 mm, 7 mm, and 10 mm were used to simulate bony destruction. The Frankfort horizontal plane of the dry skull was kept horizontally in panoramic radiography. The 2 mm thick scans were exposed parallel to the Frankfort horizontal plane of the dry skull in CT. The results obtained are as follows : 1. Bony defects, with diameters of 5 mm, 7 mm, and 10 mm in the center of the maxillary sinus posterior wall, were not detected by panoramic radiography. With CT, bony defects with diameters of 5 mm, 7 mm, and 10 mm were detected respectively by 4 slices, 6 slices, and 7 slices of the image. 2. A bony defect with a diameter of 5 mm in the posterior wall, facing the pterygopalatine fossa, was not detected by panoramic radiography and CT. However, bony defects with diameters of 7 mm and 10 mm were detected by both examinations. With CT, bony defects with diameters of 7 mm and 10 mm were detected respectively by 6 slices and 7 slices of the image. 3. A bony defect with a diameter of 5 mm in the posterior wall, above the maxillary tuberosity, was not detected by panoramic radiography. However, bony defects with diameters of 7 mm and 10 mm were detected by panoramic radiography. With CT, bony defects with diameters of 5 mm, 7 mm, and 10 mm were detected respectively by 4 slices, 7 slices, and 8 slices of the image. 4. Bony defects, with diameters of 5 mm, 7 mm, and 10 mm in the posterior wall adjacent to the zygomatic process of the maxilla, were not detected by panoramic radiography. With CT, bony defects with diameters of 5 mm, 7 mm, and 10 mm were detected respectively by 4 slices, 7 slices, and 8 slices of the image. 5. Bony defects, with diameters of 5 mm, 7 mm, and 10 mm in the zygomatico-alveolar region of the maxilla, were detected by panoramic radiography and CT. With CT, bony defects with diameters of 5 mm, 7 mm, and 10 mm were detected respectively by 3 slices, 5 slices, and 6 slices of the image. Noting above findings, it is clear that bony defects with a larger diameter than 7 mm in the posterior wall, facing the pterygopalatine fossa and above the maxillary tuberosity and bony defects with a larger diameter than 5 mm in the zygomatico-alveolar region of the maxilla may be better detected using panoramic radiography. However, panoramic radiography has limitations in the ability to diagnose maxillary sinus disease because the anterior and posterior walls of the maxillary sinus are superimposed on the medial wall. The findings of the study indicate that when CT is used as a follow-up to panoramic radiography in examination of maxillary sinus disease, the results from the panoramic radiography should be consulted.