MRI is a non-invasive diagnostic study of minimal risk which uses magnets instead of ionizing radiation to acquire images. The images are then assembled by computer. Diffusion tensor imaging (DTI) uses water diffusion to visualize structures in the brain and nervous system. Tractography is performed using DTI and computer post-processing to track the fiber bundles which exist in the brain and spinal cord and visualize them as two and three dimensional images. Both techniques allow radiologists to detect abnormalities, in this case, cervical spine disc herniation.