Quantitative Analysis of Magnetic Resonance Image Sagittal T2 Mapping in Lumbar Spine Classification

Objective: To evaluate the significance of T2 value changes of nucleus pulposus and annulus fibrosus in intervertebral disc degeneration, and to discuss feasibility and effectivity of intervertebral disc classification through MRI sagittal T2 mapping (specifically based on sagittal multi-echo SE sequence T2 mapping). Methods : 35 healthy volunteers (including 20 males and 15 females, aged 20 to 48, average age is 36.8) were randomly selected and their intervertebral discs of L3/L4, L4/L5 and L5/S1, with a sum-up of 90 discs, were scanned by sagittal MRI using routine FSE sequence as well as multi-echo SE sequence. T2 mapping was handled by image post-processing and each intervertebral disc was classified. T2 values of nucleus pulposus and annulus fibrosus were measured and statistical analysis were performed to study the relationship between T2 values and ages, disc grades or disc locations. Results: In classification through MRI sagittal T2 mapping, the disc grade increased along with the decrease of disc location or the increase of age. T2 value of nucleus pulposus decreased along with the increase of age (P < 0.05). There was a significant difference in T2 mean values of nucleus pulposus of different grades (P < 0.05). Conclusion: MRI sagittal T2 mapping provides us with a classification of intervertebral disc based on T2 values. Through evaluation of T2 mapping and measurement of T2 values of nucleus pulposus and annulus fibrosus, early stage degeneration of intervertebral disc can be monitored and the its relationship with relevant factors can be studied.