Visualization of Disc Degeneration: Comparison between Magnetic Resonance Imaging and Discography

ABSTRACT

OBJECTIVE: To determine the relationship between magnetic resonance imaging (MRI) and discography in visualization of disc degeneration. METHOD: Forty-eight patients with suspected discogenic pain in lumbar spines and degenerative changes of the lumbar intervertebral discs in T2-weighted magnetic resonance imaging were studied. Five types of discogram (cottonball, lobular, irregular, fissured, and ruptured) were classified by identifiable features in shape and density of radio-opaque shadow. Three types of MRI (bulging, protrusion, and extrusion) were classified by degrees of disc herniation. The correlation between two imaging techniques of lumbar intervertebral discs were analyzed using Spearman's correlation coefficient. RESULTS: Of sixty-three discs, MRI finding of the disc herniation revealed as follows: bulging, 17 discs; protrusion, 20 discs; extrusion, 26 discs. Discography revealed as follows: cottonball, 15 discs; lobular, 2 discs; irregular, 11 discs; fissured, 10 discs; ruptured, 25 discs. 46 discs of 63 discs showed internal structural abnormalities (irregular, fissured, or ruptured). There was no statistically significant correlation between MRI and discography in visualization of the disc degeneration (r=0.081). CONCLUSION: Severity of the lumbar intervertebral disc degeneration in MRI was not correlated with degenerative severity of discographic imaging. Supplementary discography may be useful in evaluation of patients with discogenic pain since discographic imaging when compared to MRI visualizes disc degeneration more accurately.