A Diffusion Tensor Imaging Group Study of the Spinal Cord in Multiple Sclerosis Patients With and Without T2 Spinal Cord Lesions

Purpose: To examine the T-2-normal appearing spinal cord of patients with multiple sclerosis (MS) using diffusion tensor imaging. Materials and Methods: Diffusion tensor images of the spinal cord were acquired from 21 healthy subjects, 11 MS patients with spinal cord lesions, and 10 MS patients without spinal cord lesions on the T-2-weighted MR images. Different diffusion measures were evaluated using both a region of interest (ROI) -based and a diffusion tensor tractography-based segmentation approach. Results: It was observed that the FA, the transverse diffusivity lambda(perpendicular to), and the ratio of the longitudinal and transverse diffusivities (lambda(parallel to)/lambda (perpendicular to))were significantly lower in the spinal cord of MS patients with spinal cord lesions compared with the control subjects using both the ROI method (P = 0.014, P = 0.028, and P = 0.039, respectively) and the tractography-based approach (P = 0.006, P = 0.037, and P = 0.012, respectively). For both image analysis methods, the FA and the lambda(parallel to)/lambda (perpendicular to) values were significantly different between the control group and the MS patient group without T-2 spinal cord lesions (P = 0.013). Conclusion: Our results suggest that the spinal cord may still be affected by MS, even when lesions are not detected on a conventional MR scan. In addition, we demonstrated that diffusion tensor tractography is a robust tool to analyze the spinal cord of MS patients.