[Spinal osteoid osteoma, neuralgia and MRI].

Computed Tomography (CT) is the most valuable imaging modality for the diagnosis of osteoid osteoma. Magnetic Resonance Imaging (MRI) is less 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 inflammation adjacent to the nidus is the main sign. Inflammatory changes are characterized by low signal on T1-weighted sequence, high signal on T2 and enhancement after gadolinium IV administration. These changes are not specific. But in these 2 cases, an osseous abnormality was detected and the nidus was suspected even if MRI was less conspicuous than CT. In case of children or young adults with radiculalgia and normal disk, inflammatory localized changes in MRI must be suspicious of the diagnosis of osteoid osteoma.