[Comparison between CT-discography and magnetic resonance imaging in lumbar disc diseases]

To investigate the clinical importance of discography and CT after discography (CTD) in the lumbar disc diseases, and make a comparison between CTD and magnetic resonance imaging (MRI).

265 patients with back and leg pain 177 males and 79 females, age 39 +/- 16, underwent discography and CT 2 hours later on 298 discs. All the patients' discs were classified into 7 types according to the findings by discography and CTD. Comprehensive MRI pictures were available in 237 of the 265 patients (with 257 discs); they accepted the MRI classification and were compared with the CT-discographic findings.

245 patients underwent operation, among which 247 discs showed visual lesions during the procedure and 238 cases (96.4%) had their disc diseases diagnosed accurately through discography and CTD. Considering the positive screening rate for the discogenic abnormality, the difference was of statistical significance between the CTD and MRI groups (P < 0.01). MRI was considered to have limited value in the disc diseases with passive discographic finding.

Discography is an efficient, sound and safe assistant diagnostic tool, which can get some special information about disc. The matched-group study shows that the MRI and CTD can not be re placed by each other. MRI may act as the screening tool for disc diseases, but is inferior to CTD, especially for the contiguous disc structure in the spinal fixation procedure.