Imaging of bone micro-injuries.

PURPOSE

We evaluated the fundamental signs of each imaging modality to define the role of MRI in identifying and characterizing bone micro-injuries.

MATERIALS AND METHODS

We retrospectively reviewed 50 MRI examinations performed after preliminary conventional radiography on 25 stress fractures and 25 insufficiency fractures between 1989 and 2002. The number of lesions identified was 55: 11 were evaluated with CT and 9 with radionuclide bone scan.

RESULTS

Although bone micro-injuries have different pathogenetic mechanisms, the final outcome is a cortical and/or spongy bone fissure, followed by repair processes. Conventional x-ray showed the presence of a lesion in 24/55 cases. Radionuclide bone scanning allowed suspicion or confirmation of the lesion in 8/9 cases. MR identified the lesion in all cases. CT allowed recognition of the lesion in 10/11 cases.

CONCLUSIONS

When a bone micro-injury is suspected following conventional radiography, MRI is the most sensitive and specific modality able to complete the diagnostic work-up.