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

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/mm(2)) 1 h apart. Regions of interests were drawn around target metastasis and normal liver in each patient to derive ADC (all b values), ADC(high) (b values a parts per thousand yen100 s/mm(2)) and intravoxel incoherent motion (IVIM) parameters f, D (*) and D by least squares data fitting. Short-term measurement reproducibility of median ADC, ADC(high), f, D (*) and D values were derived from Bland-Altman analysis. The measurement reproducibility for ADC, ADC(high) 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. aEuro cent Quantitative diffusion-weighted MRI parameters are increasingly used for clinical management decisions. aEuro cent However perfusion-sensitive intravoxel incoherent motion (IVIM) parameters showed poor measurement reproducibility. aEuro cent Measurement reproducibility of IVIM parameters was worse in metastases than normal liver. aEuro cent Efforts to improve measurement reproducibility of IVIM parameters should be explored.