Relevance of spinal lesions in chronic non-bacterial osteomyelitis and imaging features on whole body MRI.

Chronic non-bacterial osteomyelitis (CNO) is an autoinflammatory bone disorder that usually involves long bone metaphyses of the lower extremities and can affect the clavicles, pelvis, mandible, sternum, and spine. The spine is recognized as a classic feature of CNO, but routine whole-body MRI with coronal-only STIR images may underreport its frequency. Dedicated sagittal spinal imaging is important not only in proving a multifocal process but also because vertebral height loss and vertebra plana in CNO can result in scoliosis and kyphosis. Aggressive treatment can prevent vertebral collapse and promote vertebral body height recovery. Spinal CNO typically involves the thoracic spine, is often multifocal, usually shows non-contiguous vertebral involvement, and demonstrates abnormal high T2W signal at the vertebral body and endplate destruction-sometimes as a spondylodiscitis. Importantly, in distinguishing it from other potential causes, CNO usually has no soft tissue mass. Treatment with pamidronate may result in a bone-in-bone appearance.