[Magnetic resonance in the diagnosis of bone infections]

Skeletal infections represent a variety of clinical and pathological conditions in which both an early diagnosis and the precise evaluation of disease extent are very important in planning proper therapy. To determine MRI capabilities and limitations in the evaluation of skeletal infections 21 patients--12 with a clinical diagnosis of osteomyelitis of the lower limbs and 9 with a clinical diagnosis of spondyloscitis--were studied with this technique. All patients were examined with conventional X-rays; conventional tomography was performed in 3 cases, and CT in 6. Signal intensities and morphological aspects were then evaluated with MRI. MRI diagnoses were compared with surgical findings or clinical follow-up, after antibiotic therapy: 19 true-positives were observed, together with 1 true-negative, 1 false-positive, and no false-negatives. MRI findings were correlated with those of conventional radiology: MRI identified the lesions and their nature in 100% of cases, whereas conventional radiology did the same in 85% of cases; in 50% of cases only the latter was able to define the nature of the process. Four patients underwent MRI follow-up. MRI was highly sensitive in determining the presence of lesions in an early stage and in demonstrating lesion regression. Moreover, MRI was able to identify the complications occurring in some cases of osteomyelitis and spondyloscitis. In all cases MRI allowed the extent of the disease to be accurately determined and, in osteomyelitis of the lower limbs, it was extremely useful to differentiate soft-tissue infections from bone marrow involvement.