The Relationship Between Morphology of Lumbar Disc Herniation and MRI Changes in Adjacent Vertebral Bodies

  Background: Intervertebral disc herniation has two common types, extrusion and protrusion, which may affect the adjacent vertebrae.In addition, it is associated with significant signal changes in T۱ MRI (short TR/TE) and T۲ MRI (long TR/TE).   Methods: The present study is a cross-sectional analytic one, in which sampling was performed retrospectively. Cases were randomly selected from the patients undergoing discectomy in our department in a one-year period. Before surgery, MRI images, T۱-weighted and T۲-weighted sagittal cuts were interpreted by an expert radiologist. Signal intensity of the upper and the lower adjacent vertebra and the operated herniated disc were compared with the normal discs, both in T۱-weighted and T۲-weighted. Changes in signal intensity were recorded in qualitative variables. Statistical analysis was then performed between two groups. Results: In the present study, we have evaluated ۱۷۰ patients undergoing lumbar disc herniation surgery, which included ۹۷ protruded and ۸۶ extruded discs. The patients’ age ranged from ۲۱ to ۷۸ years old, with an average of ۴۳.۰۳ ±۱۱.۴ years. Evaluating the type of discopathy with the presence of signal changes (hypo or hyper signal changes) demonstrated more signal changes in upper adjacent vertebrae in T۲-weighted MRI (۴۵.۳%). However, patients with protruded discs showed less changes (۳۰.۹%). It showed that the difference was statistically significant (P<۰.۰۵). Conclusion: Extruded discs are associated with increased signal in T۱-weighted MRI (short TR/TE) in the upper adjacent vertebrae. Signal changes in T۲-weighted MRI (long TR/TE) in upper adjacent vertebrae are significantly more common in extruded discs, in comparison with protruded discs.

Keywords:

Extrusion , Lumbar disc herniation , MRI , Protrusion , Signal change