[Helical CT and diagnostic evaluation of cranio-facial fibrous dysplasia]. / Scanner spiralé et bilan diagnostique de dysplasie fibreuse cranio-faciale.

ABSTRACT

PURPOSE: To evaluate the role of helical CT in the evaluation of skull abnormalities seen in fibrous dysplasia. MATERIALS AND METHODS: Prospective study on 6 cases with cranio-facial fibrous dysplasia (3 males and 3 females) aged 8 to 59 years old, evaluated with plain radiographs, helical CT and, in 1 case, MRI. Helical CT was performed in 3 cases on a CT Twin scan (Elscint), in 3 cases on a Somatom Plus scan (Siemens). Multiplanar reconstructions and 3D reconstructions were done in all cases. 4 cases had a histopathological confirmation of fibrous dysplasia lesions by bone-biopsy (3 cases) or surgical biopsy (1 case). RESULTS: The 6 cases included sclerotic form in 3 cases, cystic variety in 1 case, polyostotic variety in 1 case, mixed form in 1 case. Topographic localizations of fibrous dysplasia were skull base involvement in 1 case, multizonal skull involvement in 4 cases, maxillo-mandibulary involvement (cherubism) in 1 case. CONCLUSION: Helical CT is an optimal method to evaluate the skull lesions of fibrous dysplasia. The review of source images must always be done. 3-dimensional bone reconstructions are better to visualize the anterior cranial vault and skull base dysmorphy. Helical acquisition is a compromise in case by case between the dose of irradiation and the quality of source images.