Efficacy of pamidronate therapy in children with chronic non-bacterial osteitis: disease activity assessment by whole body magnetic resonance imaging

Objective. The aim of this study was to describe the efficacy of pamidronate therapy on disease activity in children with chronic non-bacterial osteitis (CNO) using whole body MRI (WB-MRI). Methods. Clinical assessment and WB-MRI were obtained in 11 children before and after 1 year of pamidronate therapy using a 1.5 T MRI scanner and short tau inversion recovery sequences. The images were reported by a paediatric radiologist. Results. WB-MRI identified 75 lesions in 11 patients; 16 of these lesions had not been detected by clinical examination. Follow-up MRI after 1 year of pamidronate showed complete resolution of inflammation in 45 lesions, moderate improvement in 10 lesions and no change in 20 lesions. Two new lesions developed while on treatment. Conclusion. WB-MRI allows a more accurate assessment of the disease extent in CNO than clinical examination alone and is useful in the objective measurement of treatment efficacy. Pamidronate appears to be an effective treatment in children with CNO unresponsive to NSAIDs.