【摘要】 目的探讨颈髓 MR 扩散张量成像(DTI)合适的扫描参数。方法对80名成年健康志愿者行颈髓常规 MR 及 DTI 检查,比较不同扫描参数[扩散敏感系数(b)值、扩散敏感梯度方向数、激励次数(NEX)及层厚]对图像质量的影响。第1组,b 值分别取400、700、1000 s/mm~2;第2组,扩散敏感梯度方向数分别取6、13、25个;第3组,NEX 分别取2、4、8次;第4组,层厚分别取2、3、4 mm。并由2名高年资放射科医师采用双盲法对图像质量进行评分,据此对不同图像进行比较。结果在4种不同扫描参数的比较中,b 值为700 s/mm~2时图像质量最好[(2.25±0.58)分],与 b 值为400 s/mm~2[(1.86±0.53)分]和1000 s/mm~2[(1.48±0.35)分]时比较差异有统计学意义(P<0.05);扩散敏感梯度方向为25个时图像质量最好[(2.58±0.59)分],与方向为6个[(1.33±0.36)分]和13个[(1.90±0.51)分]时比较,差异有统计学意义(P<0.05);NEX 为4的图像质量[(2.45±0.63)分]最好,与 NEX 为2[(1.47±0.32)分]和8[(2.29±0.55)分]比较,差异有统计学意义(P<0.05);层厚为4 mm 的图像质量[(2.41±0.55)分]最好,与层厚2 mm[(1.54±0.27)分]和3 mm[(1.87±0.48)分]比较,差异有统计学意义(P<0.05)。结论选择合适的颈髓 DTI 扫描参数,有利于临床对颈髓细微结构的研究。更多还原

【Abstract】 Objective To investigate the optimal scanning parameters for diffusion tensor imaging of the cervical cord.Methods MRI and diffusion tensor imaging of the cervical cord was performed in 80 healthy adult volunteers.Different parameters including b values,the number of the diffusion sensitive gradient directions,the number of excitations,and slice thickness were applied and their effects on the quality of the images were compared.DTI was performed on the cervical spinal cord with different b-values (400,700,and 1000 s/mm~2)in group 1,with different numbers of diffusion gradient directions(6,13, and 25)in group 2,with different numbers of excitations(2,4,and 8)in group 3,and with different slice thicknesses(2,3,and 4 mm)in group 4.Two radiology experts gave a score to every image with double blind methods,then compared the image quality.Results In the comparison of the four different parameters,DTIs using a b value of 700 s/mm~2(2.25±0.58)showed better image quality than those with the b values of 400 s/mm~2(1.86±0.53)and 1000 s/mm~2(1.48±0.35)(P<0.05).DTIs using directions of 25(2.58±0.59)showed significantly better image quality than those with the directions of 6(1.33±0.36)and 13(1.90±0.51)(P<0.05).DTIs using excitation of 4(2.45±0.63)showed better image quality than those with 2(1.47±0.32)and 8(2.29±0.55)excitations(P<0.05).DTIs using a slice thickness of 4 mm(2.41±0.55)showed better image quality than those with slice thicknesses of 2 mm(1.54±0.27)and 3 mm(1.87±0.48)(P<0.05).Conclusion Choosing suitable scanning parameters of DTI is useful for studying the minute structures of cervical cord in the clinic.更多还原