Chronic recurrent multifocal osteomyelitis (CRMO) is a non-infectious inflammatory bone disease of unknown origin. The extension of CRMO is currently evaluated with bone scintigraphy. The objectives of our study are to describe the results of the non-invasive whole-body magnetic resonance imaging (WB MRI) procedure in children with CRMO, and to discuss the interest of WB MRI in CRMO’s follow-up.

We performed a retrospective chart review of children followed for CRMO in the French center for auto-inflammatory disorders, selecting those who had a WB MRI at diagnosis and/or during follow-up. Clinical, biological, pathological and imaging findings were depicted.

There were six girls and three boys, aged 8 to 14 years. All had multiple painful localizations with increased inflammatory markers, except one. The most frequent sites involved on WB MRI were the pelvis, the femurs and the tibias. We also described extra-osseous lesions (intra-articular effusion, myositis) and for the first time polyseritis that could not be caught by X-rays or scintigraphy. Comparison with scintigraphy in three patients showed that spinal, pelvic and femoral lesions were better seen with WB MRI. WB MRI at 12 months follow-up was available in five patients, showing a clear improvement in four of them. Surprisingly, the last patient had a clinical improvement with worsening lesions on WB MRI.

The WB MRI may contribute to the diagnosis and facilitate the follow-up of children with CRMO. This non-invasive, non-irradiating procedure will also allow depicting more precisely the natural history of bone and extra-osseous lesions in CRMO.