Role of advanced magnetic resonance imaging in the assessment of malignancies of the mediastinum

Table 1 Diffusion weighted derived parameters of different model analysis

Mono-exponential model
ADC	Apparent diffusion coefficient	Exponential signal decay of water molecules in a voxel by voxel basis.
IVIM-derived parameters
D	True diffusion of H2O molecules	Not influenced by movement of water molecules within capillaries
f	Perfusion contribution to diffusion signal	Fractional volume of flowing water molecules within capillaries
D	Perfusion contribution to diffusion signal decay	Amount of non-diffusional random movements of water molecules
DKI-derived parameters
Dapp	Apparent diffusion	Estimation of diffusion coefficient in the direction parallel to the orientation of diffusion sensitizing agents
Kapp	Apparent diffusional kurtosis	Measures the deviation of the true diffusion from a Gaussian pattern.
DTI-derived parameters
MD	Mean diffusivity	Reflects the average diffusion of water molecules in all three directions.
FA	Fractional anisotropy	Measures the extent to which diffusion is non-uniform in the three orthogonal directions.

ADC: Apparent diffusion coefficient; IVIM: Intravoxel incoherent motion; MD: Mean diffusivity; FA: Fractional anisotropy.