【摘要】 目的评价1.5T和3.0T两种不同的磁场强度对膝关节影像质量的影响。方法采用同一厂家、同一系列、不同磁场强度的两种成像设备,对16位健康自愿者在1.5T和3.0T两种不同的磁场强度下,分别进行膝关节成像,序列使用相同的参数,不校正磁场强度的变化对TR的影响。分别测量半月板、肌肉、脂肪和骨骼的信噪比、对比噪声比和相对对比度,进行定量分析。结果3.0T条件下膝关节图像的信噪比和对比噪声比明显优于1.5T,差异有统计学意义;3.0T条件下膝关节图像的相对对比度与1.5T比较,没有明显的统计学差异。结论膝关节图像的信噪比和对比噪声比均随着场强的增加而提高,膝关节图像的相对对比度随场强的变化并不敏感。更多还原

【Abstract】 Objective To assess the effect of field strength on magnetic resonance imaging of knee.Methods 16 healthy volunteers were imaged at two similarly equipped MR imagers of the same generation and from the same manufacturer.The same imaging sequences were used with identical parameters and without repetition time correction for field strength.Imaging was performed in the same anatomic locations: the knee.Quantitative image analysis involved calculation of signal-to-noise ratio,contrast-to-noise ratio and relative contrast.Results SNR(signal-to-noise ratio) and CNR(contrast-to-noise ratio) increased nonlinearly with field strength,3.0T was judged superior to 1.5T images(P<0.05),relative contrast was not as dependent on field strength.Image quality was judged to be equivalent at 1.5T and 3.0 T.Conclusion Excellent image quality was obtained with two kinds of field strengths.Compared to 1.5T,SNR and CNR were promoted at 3.0T.However,relative contrast had no significant differences.更多还原