Chronic Noninfectious Osteomyelitis: A Review of Imaging Findings

Chronic noninfectious osteomyelitis or chronic nonbacterial osteomyelitis (CNO), also known as chronic recurrent multifocal osteomyelitis, is an autoinflammatory bone disorder primarily affecting the pediatric age group. Currently, it is diagnosed on the basis of clinical, laboratory, and imaging features. Imaging plays a crucial role in the diagnosis and follow-up of CNO with whole body magnetic resonance imaging (WBMRI) being the main modality. Radiographs assist in exclusion of common differential diagnoses like infections and malignancy. WBMRI aids in disease detection and exclusion of differential diagnoses, identifies additional lesions, and has a role in ascertaining the pattern of bony involvement which helps with prognostication and grading. Recent recognition of specific morphological and distribution patterns on WBMRI is increasingly allowing an upfront diagnosis of this entity to be made on imaging alone. It is also helpful for assessment of response to therapy during follow-up. This review aims to summarize the role of imaging in the evaluation of CNO, with special emphasis on WBMRI in its assessment.