[The role of computerized tomography in the diagnosis of osteoid osteoma].

Radiological diagnosis of osteoid-osteoma is based upon conventional radiographic techniques, i.e. plain film and tomography, scintigraphy and Computed Tomography (CT). The authors report on the use of CT in 13 patients affected by histologically verified osteoid-osteoma, in different locations, as related to their main clinical and epidemiological signs. A comparison is made of the diagnostic contribution of the different techniques, including scintigraphy and tomography, when available. CT results were evaluated referring to fundamental semiologic elements, such as the presence of the nidus--with or without calcifications--of perilesional sclerosis, hyperostosis and periosteosis. As a rule, we can affirm that CT allows a better spatial location in the metaphysodiaphyso-epiphyseal areas, the only exception being represented by location in the metacarpal and phalangeal bones, which are better evaluated in the axial plane due to their thinness. CT is otherwise indispensable for a correct evaluation of the posterior vertebral arch.