Complex sentence: These include mixtures of diffusion tensors Tuch2002, Q-ball imaging Tuch2004, diffusion spectrum imaging Wedeen2005 and fiber orientation distribution functions Jansons2003 Tournier2004, which typically require acquisition with a large number of gradient directions.
Split into simpler sentences: These include mixtures of diffusion tensors Tuch2002, Q-ball imaging Tuch2004, diffusion spectrum imaging Wedeen2005 and fiber orientation distribution functions Jansons2003 Tournier2004. Many of these approaches require acquisition with a large number of gradient directions.