Intravoxel incoherent motion diffusion-weighted MR imaging of the liver using respiratory-cardiac double triggering

To investigate the influence of respiratory-cardiac double triggering (RCT) on intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) for the liver, twelve healthy volunteers underwent liver DWI twice respectively with respiratory triggering (RT) and RCT schemes. Signal-to-noise ratios (SNRs) of the images, values, repeatability (evaluating with within-subject coefficient of variation), and variability of quantitative parameters, including apparent diffusion coefficient (ADC), pure diffusion coefficient (D), perfusion fraction (f), and perfusion-related diffusion coefficient (D*), were evaluated for each DWI sequence. Results showed that the use of RCT scheme significantly enhanced SNRs (P < 0.001), improved the measurement precision (P ≤ 0.023) and repeatability (P ≤ 0.009) of ADC, D, and f values, decreased the variability of ADC and D values (P ≤ 0.015). Furthermore, this improvement was not completely confined to the left liver lobe, but also observed for the right liver lobe. Moreover, the precision of D* values in the right lobe (P < 0.001) and its repeatability in the left lobe (P = 0.002) were also significantly improved. Thus, our findings suggest that RCT is a more effective physiological scheme for improving SNRs, the precision, repeatability, and variability of quantitative parameters than RT for IVIM-DWI in the liver.