Objective To assess the value of free-breathing 3D phase sensitive inversion recovery (PSIR) turbo FLASH for demonstrating the left ventricular myocardial scar in patients with myocardial infarction.Methods Twenty-three patients with myocardial infarction underwent 2D and 3D phase sensitive inversion recovery (PSIR) Turbo FLASH sequences 10-15 minutes after injection of dimeglumine gadopentetate.The image quality,the area,location and volume of hyperenhanced scar were independently assessed by two experienced radiologists.Student′s t test or rank sum test and Pearson linear correlation were used for the statistics.Results There were no significant differences in the overall image quality (2.57 ±0.59 vs 2.39 ±0.66,Z=-0.93,P =0.35),the area (24.48 ±10.83 vs 29.00 ± 11.56,Z=-1.41,P =0.16) and location ( 16.78 ± 6.51 vs 18.87 ± 6.76,Z =- 1.17,P =0.24) of hyperenhanced scar between 2D and 3D PSIR sequences.The mean volume of hyperenhanced scar was significantly greater in 3D PSIR sequence than that in 2D PSI R sequence [(23.46 ± 10.61 ) vs (31.65 ±　 13.86) cm3,t =-2.25,P =0.03].There was a good correlation in the volume of hyperenhanced scar between 2D PSIR and 3D PSIR sequences (r=0.940,P＜0.01 ;y =2.851 + 1.228x,R2 =0.883).Conclusion Free-breathing 3D PSIR Turbo FLASH is a promising new imaging technique for accurate assessment of myocardial scar.