Dynamic MR imaging of osteoid osteomas: correlation of semiquantitative and quantitative perfusion parameters with patient symptoms and treatment outcome.

OBJECTIVE

To evaluate the relationship between multiple MR perfusion parameters and symptoms of patients with osteoid osteomas after percutaneous laser therapy.

METHODS

MR perfusion studies of 20 patients diagnosed with an osteoid osteoma, treated with CT-guided percutaneous laser therapy, were retrospectively evaluated. Multiple perfusion parameters correlated with the treatment outcome and the presence of osteoid osteoma-related symptoms.

RESULTS

There were 16 successful treatments, 6 recurrences and a significant difference in the perfusion parameters of these groups (P < 0.0001). Patients with successful treatment demonstrated delayed progressive enhancement or no enhancement (mean time to peak = 182 s, mean delay to the arterial peak = 119.3 s). Patients with treatment failure demonstrated an early and steep enhancement (mean time to peak = 78 s and mean delay to the arterial peak = 24 s). Plasmatic volume and transfer constant values significantly changed after successful treatment (P < 0.008). MR perfusion has a sensitivity and a specificity higher than 90 % in the detection of recurrent osteoid osteomas.

CONCLUSION

The identification of an early and steep enhancement with short time to peak and a short delay between the arterial and nidus peaks on MR perfusion in the postoperative setting is highly indicative of an osteoid osteoma recurrence. Key points • Magnetic resonance perfusion is becoming widely used for several tumours. • MR perfusion measurements correlate well with osteoid osteoma-related symptoms. • MR perfusion has high diagnostic performance for osteoid osteoma recurrence. • MR perfusion can improve the diagnostic confidence of osteoid osteoma recurrence.