Osteomyelitis Diskitis

  • Etiology: infection starting in vertebral endplates and then spreading into disk space, can be due to bacterial (Staphylococcus aureus) or viral
  • Radiograph: takes 2-4 weeks for disk space narrowing and end plate erosion to occur, 6-10 weeks for flattening of vertebral body
  • Bone scan with SPECT: positive earlier than plain films with increased uptake in disk spaces and vertebral bodies
  • CT: defines paravertebral soft tissue masses, epidural involvement, vertebral body involvement
  • MRI: disk signal isointense on T1 and decreased on T2, marrow signal decreased on T1 and increased on T2, best to check for epidural abscess
  • Clinical: usually in < 5 years old due to increased regional vascularity of vertebral endplates / intradiscal extension of end arteries, usually in lumbar spine at L2-3 / L3-4

Cases of Osteomyelitis Diskitis

MRI of osteomyelitis of the spine
Coronal T1 MRI without contrast of the lumbar spine (left above) shows areas of low signal intensity on the right side of the L4 and L5 vertebral bodies and a right-sided paraspinal mass all of which enhance after the administration of contrast (right above). Axial T2 MRI through the L5 vertebral body (below) shows high signal intensity in the right side of the vertebral body and in the right paraspinal mass. The disk spaces are not involved.
Radiograph and MRI of diskitis / osteomyelitis
Lateral radiograph of the lumbar spine shows loss of height of the L3-L4 intervertebral disc space. Sagittal T2 MRI of the lumbar spine shows (right top) loss of normal bright signal of the L3-L4 intervertebral disc and an epidural mass just posterior to the L4 vertebral body. Axial T1 MRI with contrast at the L4 level shows the epidural mass to be right sided and to also involve the right psoas muscle.
Radiograph and CT scan and MRI scan of diskitis / osteomyelitis of the spine
Lateral radiograph of the spine shows anterior wedging of the T12 vertebral body and loss of height of the T12-L1 intervertebral disk space. Axial CT through T12 shows destruction of the vertebral body anteriorly and an associated paraspinal abscess forming between the aorta and the vertebral body. Sagittal T2 MRI (left), T1 MRI without contrast (middle) and T1 MRI with contrast (right) demonstrate more clearly the irregular contour of the inferior endplate of T12, the loss of height of the T12-L1 intervertebral disk space, and the loss of the normal bright signal within that disk space on T2 weighted-imaging.