Abstract： Objective:To investigate the effect of water-fat separation (Dixon) and spectrally selective attenuated inversion recovery (SPAIR) on fat suppression in the neck.Methods:From June to December 2018, 35 patients, including 16 males and 19 females, aged 23-75 (46±13) years old underwent MRI examinations of cervical vertebrae in Sir Run Run Hospital Affiliated to Nanjing Medical University. The imaging data of Dixon and SPAIR fat suppression scanning were prospectively collected. The scanning sequences included Dixon VIBE-T 1WI, SPAIR VIBE-T 1WI, Dixon TSE-T 2WI and SPAIR TSE-T 2WI. According to the subjective evaluation, the quality of fat suppression was divided into 0-4 grades. The cases with clear depiction of the thyroid tissue on Dixon or SPAIR were counted. Fisher exact test and paired t test or rank sum test were used to compare the noise, SNR and CNR of mandible angle, glottis, thyroid and sternoclavicular joint. Results:There were 29 cases of grade 0, 4 cases of grade 1, 2 cases of grade 2 on Dixon VIBE-T 1WI, 4 cases of grade 3 and 31 cases of grade 4 on SPAIR VIBE-T 1WI group, and the difference was statistically significant ( P<0.05); 28 cases of grade 0, 5 cases of grade 1 and 2 cases of grade 2 on Dixon TSE-T 2WI, 33 cases of grade 3 and 4 on SPAIR TSE-T 2WI, and the difference was statistically significant ( P<0.05). There were 35 cases with clear depiction of the thyroid tissues on DIXON and 4 cases on SPAIR VIBE-T 1WI ( P<0.05); there were 35 cases on DIXON and 3 cases on SPAIR TSE-T 2WI ( P<0.05). At the level of mandible angle, for the SNR of sternocleidomastoid muscle, SNR and CNR of splenius capitis muscle on VIBE-T 1WI, Dixon images were better than those on SPAIR images, and the difference was statistically significant ( P<0.05); the noise, SNR of sternocleidomastoid and splenius capitis muscle on TSE-T 2WI images were more than those in SPAIR images, and the difference was statistically significant ( P<0.05). At the level of glottis, the SNR of sternocleidomastoid muscle and levator scapulae muscle in the sequence of VIBE-T 1WI and Dixon images were significantly higher than those on the images of SPAIR ( P<0.05); the noise and SNR of sternocleidomastoid muscle on Dixon TSE-T 2WI images were significantly higher than those on the images of SPAIR ( P<0.05). At the thyroid level, the noise of Dixon VIBE-T 1WI image was less than that of SPAIR image, the SNR of sternocleidomastoid muscle and levator scapulae muscle on Dixon images was greater than that of SPAIR image, and the difference was statistically significant ( P<0.05); For TSE-T 2WI sequence, the SNR of sternocleidomastoid muscle on Dixon image was greater than that on SPAIR image, and the difference was statistically significant ( P<0.05). At the level of sternoclavicular joint, there were no significant differences for noise, SNR and CNR between the two groups ( P>0.05). Conclusion:Dixon outperforms SPAIR in obtaining better image quality and suppression effect in terms of neck MRI scanning.