The image shown here are based on MRI scans acquired using diffusion tensor imaging sequences, then converted into 3-D fiber-tracking images, which use color to encode the location and direction of neural pathways.
       Diffusion Tensor Imaging (DTI), sometimes referred to as DTI with fiber tracking or tractography, can be used to track the anisotropy of diffusion in the brain. DTI is a new but rapidly evolving imaging technology that is able to determine the direction of water diffusion within confining cellular structures, such as nerve bundles, or fibers. By applying a diffusion sensitizing magnetic field gradient in multiple Cartesian directions (typically 6, 15, or 32 directions), the DTI data not only yields information on the integrity of cellular structures, but this data can also be used to create mathematical representations of the cellular structures (such as nerve fibers) in three dimensions, resulting in a pictorial view of the anatomy, which may aid in the diagnosis of specific diseases.
       A 2004 longitudinal study (four DTI scans in seven patients over one year) suggested that DTI is sensitive to microscopic changes occurring in tissue of normal appearance in conventional images and could be useful for monitoring the course of disease, even though it was unable to clearly distinguish between the various pathophysiological processes involved. The authors also stated that results obtained in volunteers demonstrated preliminary verification of reproducibility of the DTI methodology (1).
       Reproducibility has also been studied at Nevada Imaging Centers Spring Valley location in Las Vegas, Nevada where three of the authors are practicing (WWO, EHH, and RKR).
       Therefore, fiber tracking has the potential to elucidate some characteristics of tissue microstructure inaccessible to other MRI techniques (2) and might offer insight into the etiology of multiple sclerosis and other disease processes and/or clarification of processes noted on false negative MRI’s (3-5).

REFERENCES
1. Cassol E, Ranjeva JP, Ibarrola D, et al. Diffusion tensor imaging in multiple sclerosis: a tool for monitoring changes in normal-appearing white matter. Mult Scler 2004;10:188-96.

2. Rovaris M, Gallo A, Riva R, et al. An MT MRI study of the cervical cord in clinically isolated syndromes suggestive of MS. Neurology 2004;63:584-5.

3. Le Bihan D, Mangin JF, Poupon C, et al. Diffusion tensor imaging: concepts and applications. J Magn Reson Imaging 2001;13:534-46.

4. Maldjian JA, Grossman RI. Future applications of DWI in MS. J Neurol Sci 2001;186 Suppl 1:S55-7

5. Tench CR, Morgan PS, Wilson M, Blumhardt LD. White matter mapping using diffusion tensor MRI. Magn Reson Med 2002;47:967-72.

These images are acquired with a Philips Intera 3T MRI system running Achieva level software (Release 11.2) with ExamCards, at Spring Valley Nevada Imaging Center, Las Vegas, Nevada.