title: Application of dynamic MRI to differentiating odontogenic myxomas from ameloblastomas.
abstract: It is often difficult to radiographically distinguish odontogenic myxomas from ameloblastomas. In the present study, we tried to differentiate odontogenic myxomas from ameloblastomas using dynamic magnetic resonance imaging (dynamic MRI). Two cases of ameloblastoma with cystic components and two cases of odontogenic myxoma were compared by dynamic MRI. The dynamic MRI features of solid areas of ameloblastomas showed a rapid enhancement, reaching maximum contrast at 45-60 s, and maintained these enhancement levels or showed a gradual wash-out to 600 s thereafter; in contrast, those of the cystic areas of ameloblastomas showed no enhancement. The dynamic MRI features of the whole area of odontogenic myxomas (we considered the whole area to be the tumor substance in the odontogenic myxomas, as based on histopathological examinations) showed a gradual increase in enhancement at 500-600 s. The central portions of the odontogenic myxomas, which did not appear to be enhanced on Gd-T1 weighted images also showed a gradual increase in enhancement at 500-600 s, though the increase was minimal. These results indicate that the dynamic MRI features of odontogenic myxomas are different from those of ameloblastomas. Therefore, dynamic MRI may be a useful tool for diagnosis of myxoma.
authors.affiliation: Department of Oral and Maxillofacial Radiology, Field of Tumor Biology, Graduate School of Medicine and Dentistry, Okayama University Graduate Schools, Japan. asaumi@md.okayama-u.ac.jp
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Asaumi
authors.forename: Hidenobu
authors.initials: H
authors.lastname: Matsuzaki
authors.forename: Miki
authors.initials: M
authors.lastname: Hisatomi
authors.forename: Hironobu
authors.initials: H
authors.lastname: Konouchi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Shigehara
authors.forename: Kanji
authors.initials: K
authors.lastname: Kishi
mesh_terms: D000564:Ameloblastoma / Q000175:diagnosis*; D003287:Contrast Media; D003937:Diagnosis, Differential; D019786:Gadolinium DTPA; D006801:Humans; D007573:Jaw Neoplasms / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009808:Odontogenic Tumors / Q000175:diagnosis*
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA