Purpose: To demonstrate the applicability of inner field-of-view (FOV) echo-planar imaging based on spatially two-dimensional selective radiofrequency excitations to high-resolution diffusion tensor imaging.
Materials and methods: Diffusion tensor imaging of inner FOVs with in-plane resolutions of 0.90 x 0.90 mm(2) and 0.50 x 0.50 mm(2) was performed in the human brain and cervical spinal cord on a 3 T whole-body MR system.
Results: Using inner FOVs reduces geometric distortions in echo-planar imaging and allows for an improved in-plane resolution. Some of the crossings of transverse pontine fibers with the pyramidal tracts in the brainstem could be resolved, increased diffusion anisotropy and fiber orientation could be identified in cerebellar white matter, and the reduced diffusion anisotropy of spinal cord gray matter could be detected.
Conclusion: Inner FOV echo-planar imaging may help to improve the spatial resolution and thus the accuracy of diffusion anisotropy and white matter fiber orientation measurements in the human central nervous system.