A COMPARISON OF RADIOGRAPHIC SIGNS OF DEGENERATION TO CORRESPONDING MRI SIGNAL INTENSITIES IN THE LUMBAR SPINE

Objectives: To evaluate plain film radiographic findings of lumbar int ervertebral disk degeneration. Design: A cross-sectional observational design was employed. Contingency tables were constructed to evaluate the relationships between radiographic findings of degeneration and th e corresponding MRI signal intensities of the inner intervertebral dis k. Setting: Twenty-four consecutive cases were retrospectively selecte d from an MRI imaging center. Patients: No exclusion was made on the b asis of age or sex. Main Outcome Measures: Radiographic findings of IV D degeneration include: Narrowed disk space, osteophyte formation, end -plate sclerosis, vacuum phenomenon, end-plate irregularity and Schmor l's node formation. The inner IVD signal intensity of the sagittal T2- weighted MRI image was visually categorized by three radiologists. The signal intensities were divided into low, medium and high categories. Main Results: Visually reduced disk height, osteophytes and eburnatio n all demonstrate significant relationships with MRI signal intensity. Due to their infrequency, no significant relationships could be found with vacuum phenomena, end-plate irregularity, and Schmorl's nodes wh en compared to MRI signal intensity. Conclusions: In conclusion, visua lly reduced disk height is frequently associated with decreased signal intensity and, therefore, significantly indicates internal disk deran gement. Osteophytes are more commonly present when the signal intensit y is low. However, high signal intensity is associated with osteophyti c change as well. Therefore, osteophytic change is less sensitive and accurate to early inner disk degenerative change. When osteophytes and reduced disk height are present together, a stronger prediction of de generation is possible then when either finding is present alone. Due to their infrequency, eburnation, vacuum phenomena, end-plate irregula rity and Schmorl's nodes are less helpful indicators of degeneration.