Evaluation of intervertebral disc using T2 mapping sequences in patients undergoing O2-O3 chemiodiscolysis: an instrumental study with clinical correlation.

PURPOSE: To assess the MRI modifications of the intervertebral disc (IVD) treated by chemiodiscolysis using T2 mapping sequences. METHODS: Thirty sciatica patients (17 males, 13 females, mean age 47.52 years) were enrolled for percutaneous CT-guided O2-O3 chemiodiscolysis treatment. As a control group, we enrolled 30 patients who were treated by CT-guided periradicular injections. All patients were submitted to clinical (using VAS and Oswestry Disability index (ODI)) and imaging studies to evaluate the intervertebral disc area (IDA) and T2 mapping values of the IVD before and at 1-month follow-up. RESULTS: In the study group, pre-treatment IDA mean values were 20.47 ± 1.62 cm2, with significant reduction at the follow-up (P < 0.05). Mean pre-treatment T2 relaxation time values were 38.80 ± 4.51 ms, 44.05 ± 0.91 ms, and 45.45 ± 14.11 ms for anterior annulus fibrosus, nucleus pulposus (NP), and posterior annulus fibrosus, respectively, with significant increase at the level of the NP (P < 0.05) at the follow-up. Mean pre-treatment ODI and VAS scores were 21.5 ± 10.6 and 8.5 ± 0.57, with significant improvement at the post-treatment follow-up (P < 0.05). In the control group, despite clinical improvement, we did not find significant IVA reduction nor significant T2 values change after treatment. Correlation analysis of T2 mapping relaxation time values showed significant correlation of NP T2 mapping value with both the reduction of IDA (0.81, P < 0.001) and the improvement of VAS and ODI scores (0.86, P < 0.001) at 1 month. In the control group, we did not find any statistically significant correlation. CONCLUSIONS: T2 mapping may be a useful indicator to predict disc shrinkage and the clinical response to CT-guided O2-O3 injection.