The nuclear trial sign in thoracic herniated disks.

PURPOSE AND METHODS Postmyelography CT studies of 84 patients with 114 thoracic herniated disks were reviewed for endplate irregularity, sclerosis, and/or disk-space calcification that could suggest a migratory path of the herniated fragment. RESULTS Abnormal straight or curvilinear densities (the "nuclear trial sign") were present at the level of the disk or endplate in 46% of the cases. MR studies of 35 thoracic herniated disks were also examined. Similar changes were likewise present in 44%. CONCLUSION The frequent occurrence of this finding in the mid and lower thoracic spine renders it a useful secondary sign for thoracic herniated disks, although false positives do occur.