Separation of fiber tracts within the human cingulum bundle using single-shot STEAM DTI.

The cingulum bundle is a complex white matter fiber tract of the human brain that comprises long association fibers, commissural fibers, and various U-fibers. It is located above the corpus callosum and interconnects limbic structures. A decline of the cingulum fiber integrity has been observed in patients with mental disorders such as schizophrenia. In this work a separation of the bi-hemispheric lateral longitudinal striae and selected U-fibers was achieved by fiber tractography of the cingulum bundle based on diffusion tensor imaging at 1.8 mm isotropic spatial resolution. Anatomic accuracy without susceptibility-induced distortions was ensured by diffusion-weighted single-shot STEAM MRI with 24 gradient directions and b values of 0 and 1000 s mm -2 . Extending earlier versions, the STEAM sequence combined variable flip angles, centrically reordered phase encoding, partial Fourier encoding, and parallel imaging.