Rapid measurement of intravoxel incoherent motion (IVIM) derived perfusion fraction for clinical magnetic resonance imaging

Object: This study aimed to investigate the reliability of intravoxel incoherent motion (IVIM) model derived parameters D and f, and their dependency on b-value distributions with a rapid three b-value acquisition protocol. Materials and Methods: Diffusion models for brain, kidney and liver were assessed for bias, error and reproducibility for the estimated IVIM parameters using b-values 0 and 1000, and a b-value between 200-900, at signal-to-noise ratios (SNR) 40, 55 and 80. Relative errors were used to estimate optimal b-value distributions for each tissue scenario. Sixteen volunteers underwent brain DW-MRI, for which bias and coefficient of variation were determined in the grey matter. Results: Bias had a large influence in estimation D and f for the low-perfused brain model, particularly at lower b-values, with the same trends being confirmed by in-vivo imaging. Significant differences were demonstrated in-vivo for estimation of D (P=0.029) and f (P<0.001) with [300,1000] and [500,1000] distributions. The effect of bias was considerably lower for the high-perfused models. The optimal b-value distributions were estimated to be brain500,1000, kidney300,1000 and liver200,1000. Conclusion: IVIM parameters can be estimated using a rapid DW-MRI protocol, where the optimal b-value distribution depends on tissue characteristics and compromise between bias and variability.