Fig. (1) Imaging of the lumbar spine. (a) Longstanding disease resulted in a characteristic bamboo spine with ankylosis and osteoporosis.
(b) CT imaging revealed dural ectasia with osteolysis of the arcus posterior from lumbar vertebra 1 to 4 (L1-4) and extending into the spine
channel (arrow) on a sagittal view. (c) Transverse CT section showing arcus destruction in L3 (arrow). (d) Short TI Inversion Recovery
(STIR) MRI images show inflammation in the vertebral bodies (arrowheads) and arachnoiditis with a contrast capturing mass in the cauda
equine in continuity with the dura (arrow).