MRI三维技术在冠心病左心室瘢痕评估中的应用价值

Assessment of left ventricular myocardial scar with three-dimensional MRI

目的评价自由呼吸膈肌导航三维相位敏感反转恢复（PSIR）磁矩预准备快速小角度激发（Turbo—FLASH）序列在心脏MRI评估冠心病左心室瘢痕中的应用价值。方法23例临床有明确心肌梗死的患者，静脉注射钆对比剂，10～15min后，先行二维PSIRTurbo—FLASH序列成像。随后，立即行三维PSIRTurbo—FLASH序列自由呼吸下成像。由2名医师独立对MRI总体质量进行等级评分。再按照美国心脏学会17节段法，对左心室钆对比剂延迟强化（LGE）的面积和类型进行半定量分析，对LGE的体积进行定量评估。两种方法变量问的比较采用配对t检验或秩和检验，Pearson相关和线性回归模型评价两者之间的相关性和依存关系。结果23例心肌梗死患者的二维和三维图像，总体质量分别为（2．57±0．59）和（2．39±0．66）分（Z=-0．93，P=0．35）；瘢痕的面积积分分别为（24．48±10．83）和（29．00±11．56）分（Z=-1．41，P=0．16）；类型分别为（16．78±6．51）和（18．87±6．76）分（Z=-1．17，P=0．24）；差异均无统计学意义。三维比二维LGE体积定量更大：二维和三维分别为（23．46±10．61）和（31．65±13．86）cm^3（t=-2．25，P=0．03）。进一步分析显示延迟强化体积定量二维和三维之间呈现出良好的相关性（r=0．940，P〈0．01）和依存性（Y=2．851＋1．228x，R^2=0．883）。结论自由呼吸下三维PSIR Turbo—FLASH序列对比剂延迟增强成像比常规二维序列能够更准确地显示心肌梗死后瘢痕，是更加有效检测心肌活性的新技术。

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 vs2.39±0.66,Z= -0.93, P=0.35）, the area （24.48±10.83 vs29.00±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） ofhyperenhanced scar between 2D and 3D PSIR sequences. The mean volume of hyperenhanced scar was significantly greater in 3D PSIR sequence than that in 2D PSIR sequence[ （23.46 ± 10. 61 ） vs （31.65 ± 13.86） cm^3 ,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, R^2 = 0. 883 ）. Conclusion Free-breathing 3D PSIR Turbo FLASH is a promising new imaging technique for accurate assessment of myocardial scar.