Application of a B-spline active surface technique to the measurement of cervical cord volume in multiple sclerosis from three-dimensional MR images

Purpose: To evaluate the ability of a B-spline active surface technique to detect cervical spinal cord atrophy due to multiple sclerosis (MS) compared with intensity based contouring. Materials and Methods: In a previously reported study, the cervical spinal cords of 28 MS patients and 13 age-matched controls were imaged with a volume acquired inversion prepared fast spoiled gradient echo sequence at baseline and after one year. The images were reanalyzed using the B spline technique and the results compared with the results obtained in the original report using intensity based contouring. Results: The mean cervical spinal cord volume determined by the active surface programme was 6487 mm(3) in 28 patients compared with 7117 mm(3) in controls (P = 0.002, corrected for age and gender). The patients' cervical spinal cord volumes were associated with expanded disability status scale scores (parameter estimate = -1.21 x 10(-3), r(2) = 0.39, P = 0.001). The patients cervical spinal cord volumes did not decrease significantly over one year, unlike the mean cervical spinal cord areas at C2/3 calculated using intensity-based contouring. Conclusion: The active surface technique can detect cervical spinal cord atrophy due to MS, which has functional significance. However, this methodology is less sensitive at detecting small serial changes compared with the previously reported method.