Dependence of Intravoxel Incoherent Motion MR threshold b-value selection for separating perfusion and diffusion compartment and liver fibrosis diagnostic performance

Purpose: To explore how the selection of threshold b-value impacts Intravoxel Incoherent Motion (IVIM) diffusion parameters of PF (f), D slow (D), and D fast (D*) values and their performance for liver fibrosis detection. Materials and Methods: Fifteen healthy volunteers and 33 hepatitis-b patients were included. With a 1.5 T MR scanner and respiration gating, IVIM data was acquired with 10 b-values of 10, 20, 40, 60, 80, 100, 150, 200, 400, and 800 s/mm 2 . Signal measurement was performed on right liver. Segmented-unconstrained analysis was used to compute IVIM parameters, and six threshold b-values between 40 and 200 s/mm 2 were compared. PF, Dslow, and Dfast values were placed along the x-axis, y-axis, and z-axis, and a plane was defined to separate volunteers