Evaluation of a Polyethylene Glycol Phantom for Measuring Apparent Diffusion Coefficients Using Three 3.0 T MRI Systems

We aimed to examine the possibility that polyethylene glycol (PEG) phantoms can simulate apparent diffusion coefficients (ADCs) of malignant tumors and the effectiveness of PEG phantoms using three 3.0 T magnetic resonance imaging (MRI) systems. In particular, the correlations between PEG concentrations and ADC values, the validation of ADC measurement precision, and the stability and reproducibility of PEG phantom were verified. A phantom containing 0, 0.625, 1.250, 2.5, 5, 10, 20 mM PEG was assessed using three MRI systems. The endpoints comprised correlations between PEG concentrations and ADC, validation of ADC measurement precision and the stability and reproducibility of the PEG phantom. The correlation coefficients between PEG concentrations and the ADC of the three MRI systems and among the three MRI systems revealed negative (r approximate to - 1.000, P < 0.001) and positive (r approximate to 1.000, P < 0.001) correlations. The ADC(mean) of 2.5-20 mM PEG was significant (P < 0.05 t tests), and that at >= 10 mM PEG was < 1.0 x 10(-3) mm(2)/s. The %CV ranged from 1.20 to 4.62, and repeatability was confirmed by the 90% confidence interval. The maximum values for Difference(Change over time) and Difference(Pri.vs.New) were 0.20 and 0.19 x 10(-3) mm(2)/s, respectively. In this study, we found that PEG concentrations >= 10 mM are required to simulate the ADCs of malignant tumors (ADC < 1.0 x 10(-3) mm(2)/s). We also showed that the ADC value is easily controlled by adjusting PEG concentrations, and can be stably measured using our PEG phantom for at least 6 months. The PEG phantom can easily and stably simulate the ADC of malignant tumors with high reproducibility.