Abstract
A numerical simulation of diffusion-weighted imaging (DWI) experiments, based on the Bloch-Torrey equation, provides an additional insight into diagnosis using MRI. However, simulation of DWI for largesize models has not been performed because huge computing power is required. We have recently developed a high-speed MRI diffusion-weighted simulator. Here we extend this simulator to the diffusion tensor imaging (DTI). To simulate DTI, as a first step, one needs to calculate DWI along several directions of MPG generated by synthesis of multiple gradients. However, the simulator allows to apply a single gradient at a time to employ the speed-up techniques. To overcome this limitation, the numerical model is rotated by an angle to make MPG always directed toward the same direction. As a result, the synthesized gradients become equivalent to the single gradient and could be treated by the simulator. Finally, the calculated DWI image is rotated back to the original coordinate system. A two-dimensional DWI simulation was performed for a human brain size model and a DTI image was calculated from the obtained images. The results showed that the errors were less than 2%.
