Abstract:Objective: To analyze the relationship between quantitative measurement of fatty liver with in-phase and out-of-phase of MRI and CT attenuation value, and to evaluate the application of the quantitative measurement with in-phase and out-of-phase of MRI in the diagnosis of fatty liver. Methods: Signal intensity of in-phase and out-of-phase of MRI and CT attenuation value were measured retrospectively in 86 patients clinically suspected fatty liver. Three CT attenuation value ratios and 4 signal indexes were calculated and the relationship between the CT attenuation value ratios and the signal indexes were analyzed by Pearson correlation coefficient. The sensitivity, specificity, accuracy of signal indexes for diagnosing fatty liver at different thresholds were calculated. Results: Significantly negative correlations were shown between 3 CT attenuation value ratios and 4 signal indexes(r=-0.823~-0.917), with the highest correlation between CT attenuation value ratio of liver to spleen and signal index 1(r=-0.917, P=0.000). Signal index 1 and signal index 4 had relatively high accuracies for diagnosing fatty liver with the threshold ≥0.1 for both, with the accuracy of 86.05% and 89.53% respectively, using CT attenuation value ratio of liver to spleen ≤1 as the standard. Conclusion: Quantitative measurement with in-phase and out-of-phase of MRI significantly correlate to CT attenuation value ratio of liver to spleen, and both can be used for quantitative evaluation of fatty liver. Signal index 1 or signal index 4 is optimal in diagnosing fatty liver with the threshold ≥0.1.