Is There a Role for DWI/DTI in Spine Imaging

Diffusion-weighted MR imaging (DWI) has become very soon after its introduction one of the routine imaging techniques in the evaluation of brain disorders. Due to the technical difficulties DWI has been rarely performed in the spine and spinal cord, and the experience and knowledge is limited. The first enthusiastic article describing the use of DWI imaging for differentiation of benign from malignant vertebral fractures was published by Andrea Baur et al. from Munich in 1998 (Baur A et al. Radiology 1998). All malignant fractures in that study were hyperintense on DWI, whereas benign (osteoporotic) fractures showed low signal. Studies with quantitative measurements that followed in the literature have also shown significant difference between benign and malignant fractures (Herneth A et al. Radiology 2002). A critical point in clinical use of DWI in vertebral body fractures is the patient inclusion or exclusion criteria (Baur A et al. J Magn Reson Imaging 2006). In advanced healing process of a fracture soft callus forms with decrease of water mobility leading to false positive results. Patients with fractures older than two weeks should be excluded, as well as metastases which have undergone therapy. Necrotic tumour shows increased diffusivity and leads to false negative result. Two major technical problems in obtaining DWI of the human spinal cord are: the size of the cord and motion. Spinal cord can move independently of surrounding structures;