gms | German Medical Science

Objectives: Quantitative T2 relaxation time mapping allows a biochemical assessment of the intervertebral disc (IVD). A healthy disc is characterized by high T2 in the nucleus pulpsus (NP) and low T2 in the annulus fibrosus (AF). In Intervertebral disc degeneration a decrease in NP T2 and increase in AF T2 values can be found.

Currently it is not clear if quantitative T2 mapping is able to predict future pain.

Methods: Twenty-five patients (mean age 39 years, range 18-60; 13 male, 12 female) with low back pain and without radicular symptoms or previous surgery were assessed with MRI at baseline and at 5 year follow-up (5Y-FU) in this prospective study.

All patients were examined using a 3T MR scanner and a dedicated spine array coil. A sagittal multi-echo spin-echo sequence was used for quantitative T2 mapping. In addition standard morphological imaging was applied.

All patients were clinically assessed with a study questionnaire, VAS and Roland-Morris questionnaire (RMDQ) at 5Y-FU.

Five rectangular equally-sized regions-of-interest (ROI) were manually drawn for T2 value assessment on two central sagittal slices. The outer two ROIs were defined as the annulus fibrosus (AF) and the central 3 ROIs were defined as the nucleus pulposus (NP). The minimal NP T2 value per patient and the maximal AF T2 value per patient (representing the "worst disc") were used for correlation with clinical parameters.

Descriptive statistics and the Spearman correlation coefficient were used.

Results and Conclusion: From baseline to 5Y-FU, the mean NP T2 values decreased from 109.0 ms (±32.4) to 103.5 ms (±37.2) whilst the mean AF T2 values AF increased from 57.8 ms (±10.7) to 58.7 ms (±11.3).

The minimal NP T2 value per patient at baseline showed a significant correlation with the respective RMDQ at 5Y-FU (r=-.517; p=.008), pain present at 5Y-FU (r=-.495; p=.012), pain duration over the past 5 years (r=-.442; p=.027), new onset radicular pain duration over the past 5 years (r = -.417; p = .038), pain during walking (r = -.482; p = .015), pain during standing (r=-.468; p=.018), pain during stair climbing (r=-.513; p=.009) and pain during sitting (r=-.414; p=.040). The maximal posterior AF a did not show any correlations with clinical parameters.

Our data suggests, that MRI T2 mapping oft he lumbar intervertebral discs can predict future patient symptoms. In particular the T2 values of the nucleus pulposus are relevant for future patient pain.

This predictive potential should be examined in future studies with regard to prevention strategies.