Aims: The investigation was carried out in order to compare the accuracy of CT and MR imaging in depicting whether disk hernias were contained by the posterior longitudinal ligament (PLL). This is crucial in the evaluation of patients who are possible candidates for percutaneous nucleotomy, which is considered effective only in contained hernias.
Results: Of 124 pathologic disks examined in 114 patients, CT was more accurate than MR imaging in 7 patients due to misinterpretation of the integrity of the PLL by MR. These hernias were therefore erroneously classified as noncontained. There was consistency between the classification by CT and MR imaging in the other 117 disks, of which 109 were correct. Both methods overstaged a large hernia that was contained by the PLL, and failed to demonstrate that 7 others were noncontained.
Conclusions: CT, which has higher sensitivity in depicting calcifications, representing further contraindications to percutaneous nucleotomy, is therefore recommended as the primary examination in these patients. Additional MR imaging should be considered if the results of CT are equivocal or at variance with the clinical presentation.