Preliminary study and clinical application of diffusion-weighted fast imaging

We have been reported that diffusion weighted MR images obtained by fast scan technique is useful to reduce motion artifact which is the main problem on its clinical application. This time, we applied this method to some clinical cases. Our experiences with some points of modifications we used are reported and some problems are also mentioned on its further application in the clinical practice. We used MAGNEX 150/HP (1.5T, Shimadzu Corporation). Shimadzu Minimum Angle Shot (SMASH) sequence, which is a sequence modified from Field echo sequence, was used to obtain intravoxel incoherent motion (IVIM) enhanced images. We applied this technique to normal volunteers, and 20 patients (arachnoid cyst: 5 cases, brain tumor: 10 cases, cerebral infarction: 2 cases, others: 3 cases). Clear MR images under ECG gating were obtained, which reflects the IVIM well and proved the usefulness of this method in the clinical practice. The calculated value of apparent diffusion coefficient (ADC) was the same as that reported before. The most beneficial point was lesser motion artifact, compared with the spin echo diffusion weighted MR images used before. But, diffusion anisotropy could not be demonstrated by this method. Diffusion weighted fast MR imaging method was useful in the clinical application of MR technique. However, there remains some room for improvement, especially in the point of spatial resolution and S/N ratio. (author)