TABLE 1.

Breakdown of the number of parameters of the models used to represent the different tissue compartments. The full models without symmetry constraints (DTI and DKI) are included for comparison, but were not used in any experiments. The acronyms “AS” and “ISO” refer to axial symmetry about the z‐axis and isotropic symmetry, respectively. The amount of parameters contributed by each term γ in Equation (9) is denoted with n _γ. The total amount of parameters is denoted with n _γ

Model type	Symmetry	$n_{S_0}$	n D	n W	n C	n γ
DTI	Point	1	6	0	0	7
DKI	Point	1	6	15	0	22
DTI AS	Point + axial	1	2	0	0	3
DKI AS	Point + axial	1	2	3	0	6
DKI AS + offset	Point + axial	1	2	3	1	7
DTI ISO	Isotropic diffusion	1	1	0	0	2
DKI ISO	Isotropic diffusion	1	1	1	0	3
DKI ISO + offset	Isotropic diffusion	1	1	1	1	4

Abbreviations: AS, axially symmetric; DKI, diffusion kurtosis imaging.