Purpose or Case Report: Chronic nonbacterial osteomyelitis (CNO) is an aseptic auto-inflammatory condition that affects children and presents with insidious bone pain. Children present with a variable clinical spectrum of disease with either unifocal or multifocal pain and acute (duration < 6months) or chronic (>6 months) symptoms. The disease course may be recurrent. In some cases, patients endure multiple lesions over a course of exacerbations and remissions. Bone lesions are often in symmetrical regions. Interestingly, clinically asymptomatic bone lesions are discovered during the imaging evaluation. Patient symptoms and clinical course may mimic other diseases, making CNO often difficult to diagnose with a consequent delay in diagnosis. Children with CNO may also develop arthritis and demonstrate similar cytokine profiles with children with juvenile idiopathic arthritis (JIA), suggesting at least a partial common disease pathway.
Methods & Materials: We plan to present the multimodality imaging spectrum of CNO, focusing on the radiographic presentation along with the use of whole body MR imaging (WBMRI). We will highlight the typical CNO locations and describe the early, progressive and chronic lesion appearance. Our discussion will include descriptive features that will aid in differentiating between infectious osteomyelitis, JIA (spondyloarthritis), primary bone lesions as well as other causes of osteitis. WBMRI protocols and imaging recommendations will be included as well as approaches to CNO lesion scoring. Complications of inflammatory CNO will be discussed. Lastly, treatment approaches and rationale will be described.
Results: An organized approach should be used to evaluate CNO lesions; with particular attention to lesion location and number, marrow edema, periostitis, soft tissue inflammation, clinically occult lesions, and joint effusions.
Conclusions: Familiarity with the imaging appearance of the CNO spectrum and differential diagnosis of osteitis will allow for accurate characterization of typical CNO lesions and will assist in making a timely diagnosis which may deter unnecessary interventions.