Computed Tomography (CT) is the most valuable imaging modality for the
diagnosis of osteoid osteoma. Magnetic Resonance Imaging (MRI) is les
s performant than CT. However, in case of neuralgia, a disk disease is
searched for and MRI is often performed at first. The authors report
2 cases of MRI diagnosis of osteoid osteomas histologically proved The
presence of bone marrow and soft tissues changes consistent with infl
ammation adjacent to the nidus is the main sign. Inflammatory changes
are characterized by low signal on T1-weighted sequence, high signal o
n T2 and enhancement after gadolinium IV administration. These changes
are not specific. But in these 2 cases, an osseous abnormality was de
tected and the nidus was suspected even if MRI was less conspicuous th
an CT. In case of children or young adults with radiculalgia and norma
l disk, inflammatory localized changes in MRI must be suspicious of th
e diagnosis of osteoid osteoma.