A quantitative evaluation of diffusion-weighted MR imaging of focal hepatic lesions by using an optimal b-value for differentiation of malignant and benign tumors

In this study, we aimed to determine an optimized b -value for the characterization of focal hepatic lesions (malignant and benign tumors) and to perform a quantitative analysis of the results. To achieve this, we obtained diffusion-weighted images (DWIs) from 30 focal hepatic disease patients (liver metastasis: 20 patients, and liver hemangioma: 10 patients) by using a 1.5 T MR system and varying the b -value from 0 through 200. The experimental results revealed that at a b -value of 50, the DWIs of the lesions showed high signal-to-noise ratios (SNRs; SN R liver_meta . = 229.83 ± 19.08, SNR liver_hema . = 241.66 ± 29.02), high contrast-to-noise ratios (CNRs; CN R liver_meta . = 39.66 ± 3.87, C N R liver_hema . = 142.55 ± 12.97) and low signal intensities of the apparent diffusion coefficients (ADCs; ADC liver_meta . = 1.40 × 10 −3 ± 0.29, ADC liver_hema . = 2.55 × 10 −3 ± 0.92). The focal hepatic lesions were clearly depicted, with DW images and ADC maps corresponding well. Thus, we could present an optimized b -value ( b = 50) for the characterization of focal hepatic lesions. Additionally, the ADC values of liver lesions were found to be useful in differentiating benign from malignant tumors.