Use of Spinal Cord Diffusion Tensor Imaging to Quantify Neural Ablation and Evaluate Outcome after Percutaneous Cordotomy for Intractable Cancer Pain.

BACKGROUND

Up to 20% of patients experience only partial pain relief after percutaneous cordotomy for cancer pain.

OBJECTIVE

To determine whether diffusion tensor imaging (DTI) can quantify neural ablation and help evaluate early postoperative outcomes after cordotomy.

METHODS

Patients undergoing percutaneous CT-guided cordotomy for intractable cancer pain were prospectively studied. Pre- and postoperative assessment was made using the visual analog scale (VAS) on pain and the pain severity scores of the Brief Pain Inventory Short Form. On postoperative day 1, DTI images of the high cervical spinal cord were obtained. DTI metrics were correlated with the number of ablations as well as early postoperative pain outcomes.

RESULTS

Seven patients (4 male, mean age 53.8 ± 4.6 years) were studied. Fractional anisotropy of the hemicord was significantly lower on the side of the lesion as compared to the contralateral side (0.54 ± 0.03 vs. 0.63 ± 0.03, p < 0.001). Mean diffusivity correlated with the improvement in the VAS score at 1 week (r = 0.88, 95% CI = 0.34-1.00, p = 0.008), as well as the change in pain severity scores at 1 week (r = 0.99, 95% CI = 0.82-1.00, p < 0.001).

CONCLUSION

DTI metrics are sensitive to the number of ablations as well as early improvement in pain scores after cordotomy. DTI of the cervical spinal cord is a potential biomarker of neural ablation after percutaneous cordotomy for intractable cancer pain.