Characterization of the microstructure of the intervertebral disc in patients with chronic low back pain by diffusion kurtosis imaging

Purpose Multivariate analysis of T2-weighted signal, diffusion ADC, and DKI parameters and tractography were used to differentiate chronic non-specific low back pain (CLBP) patients and asymptomatic controls (AC). Methods A total of 30 patients with CLBP and 23 AC underwent diffusion kurtosis imaging (DKI) of lumbar spine with a 3T MRI scanner to get the ADC values and seven parameters of DKI in the nucleus pulposus (NP) of the intervertebral disc. The tractography and the tract-related parameters as other parameters were also generated to indicate the intactness of annulus fibrosus (AF). T2-grades of the discs were also quantified based on an eight-grade degeneration grading system. ADC and T2-grades were compared with DKI parameters for the differentiation of CLBP and AC groups. Results There was no difference in the T2 grades, ADC value, and multiple parameters in DKI of NP between CLBP and AC groups (P > 0.05). The average FA values in NP in AC group were found significantly higher than in the CLBP group (P < 0.05). The scores for the intactness of AF of the intervertebral discs were significantly different in CLBP and AC groups, with 90% of sensitivity and 70% specificity (P < 0.05). Additionally, there were significantly differences in the length and volume values of the AF in CLBP and AC groups (P < 0.05). Conclusion DKI is a good noninvasive method, and it might help to differentiate CLBP from AC. Particularly, the continuation of DKI tractography reflects the presence of annulus fibrosus fissures, an important character in the generation of the low back pain. Graphic abstract These slides can be retrieved under Electronic Supplementary Material. [GRAPHICS] .