Objective To quantitatively assess the liver fat content by Nav IDEAL-IQ and compare with conventional breath-hold IDEAL-IQ and magnetic resonance spectroscopy (MRS).Methods Twenty volunteers,twenty fatty liver patients and twenty patients with other liver diseases were enrolled in this study.IDEAL-IQ,Nav IDEAL-IQ and MRS imaging were performed and fat fraction (FF) were measured respectively.The results were compared by t-test to explore whether there were differences between these groups. Spearman correlation analysis was also used to test the correlation.Results No significant differences in the FF measured by IDEAL-IQ,Nav IDEAL-IQ and MRS in normal volunteers [(4.09±0.82)%,(3.94±0.83)%,(3.92±0.85)%],fatty liver [(15.5±6.1)%,(11.8±6.5)%,(1 2 .4 ± 7 .2 )% ] and other liver lesions patients [(4.20±0.84)%,(4.00±0.94)%,(3.97±0.96)%]were found between these groups (P>0.05). There was a significant positive correlation between Nav IDEAL-IQ and MRS,and the correlation coefficients of these groups were 0.959,0.786 and 0.945,respectively.Conclusion The results of Nav IDEAL-IQ of fat quantification are consistent with MRS results and it increases the success rate of fat quantitative testing.In a word,it is a noninvasive,convenient and accurate way to measure fat fraction.