Objective <p>To explore the correlation between diffusion tensor imaging (DTI) parameters and clinical symptoms of lumbar spinal stenosis (LSS) patients, as well as the predictive value of DTI parameter values for conservative treatment prognosis of LSS patients.</p> Methods <p>Prospective collection of 33 patients with LSS accompanied by unilateral lower back and leg pain, matched with 33 volunteers based on clinical baseline data. All subjects underwent 3.0T MR scans and were independently measured by two physicians within the L4-S1 nerve roots. Spearman correlation analysis was used to test the correlation between symptomatic side DTI parameter values and clinical symptoms. Using firth penalized logistic regression analysis to explore independently associated with poor outcome in conservative treatment of LSS patients, and using receiver operating characteristic curve (ROC) to test its predictive value.</p> Results <p>DTI parameters can be used to evaluate the nerve roots in patients with LSS. There is varying degrees of correlation between DTI parameter values on the symptomatic side and VAS score, JOA score, RMDQ score, and ODI score. The difference in VAS score and the single FA value between the group with good prognosis and the group with poor prognosis is statistically significant, and the area under curve (AUC) of single root FA value is the largest.</p> Conclusion <p>DTI is feasible for evaluating the nerve root symptoms of lumbar spinal stenosis, and there is a correlation between DTI parameter values and clinical symptoms. Single-root FA value is independently associated with poor outcome after conservative treatment of LSS patients.</p> Clinical trial number <p>Not applicable.</p>