Comparison of contrast-enhanced computed tomography and gadolinium-enhanced magnetic resonance imaging one year after lumbar discectomy.

Computed tomography (CT) and magnetic resonance imaging (MRI) with intravenous contrast were performed on a prospective group of 35 consecutive patients 1 year after surgery for disc herniation. The aim of the study was to compare the two methods in the analysis of postoperative changes. Computed tomography showed, compared with MRI, more extensive scar tissue in 12 patients and increased deformation of the dural sac in 5 patients. However, the nerve root was better delineated by MRI, and this facilitated the assessment of root thickening in 13 patients and root displacement, which could not be seen by CT in seven patients. MRI revealed four small protrusions that were not visible with CT. The two methods were found to be of equal value in regard to findings such as disc herniations and foraminal stenosis, which might influence the surgeons decision to perform repeat surgery.