Intravoxel incoherent motion model-based liver lesion characterisation from three b-value diffusion-weighted MRI

To evaluate intravoxel incoherent motion (IVIM) model-based liver lesion characterisation from three b-value diffusion-weighted imaging (DWI). The 1.5-T DWI data from a respiratory gated spin-echo echo-planar magnetic resonance imaging sequence (b = 0, 50, 800 s/mm(2)) were retrospectively analysed in 38 patients with different liver lesions. Conventional apparent diffusion coefficient ADC = ADC(0,800) as well as IVIM-based parameters D'aEuro parts per thousand= ADC(50,800), ADC_low = ADC(0,50), and f' were calculated voxel-wise. Sixty-one regions of interest in hepatocellular carcinomas (HCCs, n = 24), haemangiomas (HEMs, n = 11), focal nodular hyperplasias (FNHs, n = 11), and healthy liver tissue (REFs, n = 15) were analysed. Group differences were investigated using Student's t-test and receiver-operating characteristic (ROC) analysis. Mean values +/- standard deviations of ADC, D', ADC_low (in 10(-5) mm(2)/s), and f' (in %) for REFs/FNHs/HEMs/HCCs were 130 +/- 11/143 +/- 27/168 +/- 16/113 +/- 25, 104 +/- 12/123 +/- 25/162 +/- 18/102 +/- 23, 518 +/- 66/437 +/- 97/268 +/- 69/283 +/- 120, and 18 +/- 3/14 +/- 4/6 +/- 3/9 +/- 5, respectively. Differences between lesions and REFs were more significant for IVIM-based parameters than for conventional ADC. ROC analysis showed the best discriminability between HCCs and FNHs for ADC_low and f' and between HEMs and FNHs or HCCs for D'. Three instead of two b-value DWI enables a numerically stable and voxel-wise IVIM-based analysis for improved liver lesion characterisation with tolerable acquisition time. aEuro cent Quantitative analysis of diffusion-weighted MRI helps liver lesion characterisation. aEuro cent Analysis of intravoxel incoherent motion is superior to apparent diffusion coefficient determination. aEuro cent Only three b-values enable separation of diffusion and microcirculation effects. aEuro cent The method presented is numerically stable, with voxel-wise results and short acquisition times.