Pitfalls in the Reconstruction of Fibre ODFs Using Spherical Deconvolution of Diffusion MRI Data

Greg D. Parker¹, Derek K. Jones¹

We report a previously overlooked pitfall in spherical deconvolution approaches for reconstructing fibre orientation distribution functions (fODFs) through a spherical-harmonic (SH) basis. By examining single-fibre population (fibres along the same axis) cases, we are able to uncover descriptive deficiencies in the SH representation that result in spurious fODF peaks once the assumed and actual diffusive properties of the target fibrous tissue no longer agree (e.g. local degradation through disease). Through comparison with an alternative that does not rely on spherical harmonics, we are also able to suggest a viable alternative for cases where a 'one-size-fits-all' single-fibre diffusivity assumption is inappropriate.