耳下腺腫ようにおける画像診断の評価

Abstract

Ultrasonography (US), computed tomography (CT), sialography and CT-sialography were performed on 25 patients with parotid gland tumor.Diagnostic images were compared to assess their respective roles in the investigation of parotid masses to determine the most appropriate diagnostic approach.Twenty-five patients with a total of 26 lesions were included in the study and ranged in age from 28 to 75 years (mean, 51.5 years).US was performed in 25 of the patients, CT in 22, sialography in 23, and CT sialography in 13 patients.US examinations were obtained with real-time scanning using 5-MHz, 7.5-MHz and 10-MHz transducers (Toshiba SAL-30 A and Aloka SSD-125).CT was obtained using a Toshiba TCT-60A.All tumors were surgically explored and histological diagnosis was obtained for 26 lesions (23 benign, three malignant). US and CT proved equally effective in demonstrating parotid masses and predicating malignancy.These proved to be especially superior to sialography for demonstration of the tumor in most cases.As to the border, margin and shape of the tumor, examination by US and CT showed mostly similar appearances, but the internal findings of the tumor delineated by US were more coincidental with the surgical specimen than were those by CT.CT helped in establishing the relationship of the tumor mass to the facial nerve (81%).CT is most useful in assessing the position of the tumor in the deep lobe, medial side of the ramus on the mandible and the extraglandular spread of the tumor.Indication for CTsialography was limited to those cases in which the tumor was unclear on plain CT.Sialography was inferior to US and CT in the detection of parotid tumor.US was a reliable diagnostic method for detection of mass lesions in the parotid gland.The author therefore recommends US as the initial investigatory method for evaluating parotid masses.