Measurement reproducibility of perfusion fraction and pseudodiffusion coefficient derived by intravoxel incoherent motion diffusion-weighted MR imaging in normal liver and metastases

TLDR: Quantitative diffusion-weighted MRI parameters are increasingly used for clinical management decisions, but perfusion-sensitive intravoxel incoherent motion (IVIM) parameters showed poor measurement reproducibility, worse in metastases than normal liver.

Abstract: To determine the measurement reproducibility of perfusion fraction f, pseudodiffusion coefficient D * and diffusion coefficient D in colorectal liver metastases and normal liver. Fourteen patients with known colorectal liver metastases were examined twice using respiratory-triggered echo-planar DW-MRI with eight b values (0 to 900 s/mm2) 1 h apart. Regions of interests were drawn around target metastasis and normal liver in each patient to derive ADC (all b values), ADChigh (b values ≥100 s/mm2) and intravoxel incoherent motion (IVIM) parameters f, D * and D by least squares data fitting. Short-term measurement reproducibility of median ADC, ADChigh, f, D * and D values were derived from Bland–Altman analysis. The measurement reproducibility for ADC, ADChigh and D was worst in colorectal liver metastases (−21 % to +25 %) compared with liver parenchyma (−6 % to +8 %). Poor measurement reproducibility was observed for the perfusion-sensitive parameters of f (−75 % to +241 %) and D * (−89 % to +2,120 %) in metastases, and to a lesser extent the f (−24 % to +25 %) and D* (−31 % to +59 %) of liver. Estimates of f and D * derived from the widely used least squares IVIM fitting showed poor measurement reproducibility. Efforts should be made to improve the measurement reproducibility of perfusion-sensitive IVIM parameters. • Quantitative diffusion-weighted MRI parameters are increasingly used for clinical management decisions. • However perfusion-sensitive intravoxel incoherent motion (IVIM) parameters showed poor measurement reproducibility. • Measurement reproducibility of IVIM parameters was worse in metastases than normal liver. • Efforts to improve measurement reproducibility of IVIM parameters should be explored.