分析1.5T与3.0T MR定量评价体外铁浓度模型比较研究

摘要

Objective:To investigate the reliability of quantitative measurement of iron concentration in vitro model using MRI and compare the accuracy between 1.5T and 3.0T.Methods:Two sets of iron concentration in vitro models were made,ranging from 0mg/mL to 5.0mg/mL and from 0mg/mL to 1.0mg/mL,respectively.The scanning protocol included FSE/T1WI,FRFSE/T2WI,T2 map and T2* map on axial section.Two radiologists independently evaluated the MR images of the models.T1 WI signal to noise ratio (SNR),T2 WI SNR,T2,R2,T2 * and R2 * values were evaluated.Intraclass correlation coefficient (ICC) was used to evaluate the agreements of the parameters and Pearson correlation analysis was used to calculate the correlation between iron concentration and MR measurement indexes.Results:The ICCs of T1WI SNR,T2 WI SNR,T2,R2,T2 * and R2 * values evaluated by two radiologists were all more than 0.900 (P＜0.001).The relation between iron concentration and T2WI SNR,T2 and T2 * values demonstrated function relation on 1.5T or 3.0T MR scanner.At 1.5T MR scanner,when iron concentration was less than 1.5mg/mL,T1 WI SNR and R2 correlated positively with iron concentration (P＜0.05).At 3.0T MR scanner,when iron concentration was less than 2.5mg/mL,R2 * had a positive correlation with it (P＜0.001).When iron concentration was less than 0.900mg/mL,R2 and R2 * were positively correlated with it (P＜0.05).Conclusion:MRI is able to quantitatively evaluate iron concentration in vitro model reproducibly.R2 * value is the best index to evaluate the iron concentration at either 1.5T or 3.0T MR.The measureable range at 1.5T MR is wider than that at 3.0T MR.%目的:探讨MRI对体外不同铁浓度模型定量测量的可靠性,并比较1.5T和3.0T MR对体外铁浓度模型定量测定的准确性.方法:制作2组不同铁浓度体外模型,一组铁浓度范围为0～5.0 mg/mL.另一组铁浓度范围为0～1.0 mg/mL.两组铁浓度模型分别在1.5T及3.0T MR上进行扫描.扫描序列包括短轴面FSE/T1WI、FRFSE/T2WI、T2 map和T2*map.评价测量指标包括T1WI和T2WI信噪比、T2、R2、T2*和R2*值.评价指标的一致性采用组内相关系数分析.铁浓度与T1WI信噪比、T2WI信噪比、T2、R2、T2*和R2*值的关系应用Pearson相关分析.结果:两位研究者对体外铁浓度模型MR图像测量指标T1WI信噪比、T2WI信噪比、T2、R2、T2*和R2*值一致性评价的组内相关系数均大于0.900(P＜0.001).T2WI信噪比、T2和T2*值与铁浓度在1.5T和3.0T MR上均呈非线性相关.在1.5T MR上,当铁浓度≤1.5 mg/mL时,T1WISNR、R2与铁浓度呈显著性正相关(P＜0.05).R2*则在铁浓度≤2.5 mg/mL时,与铁浓度呈显著正性线性相关(P＜0.001).而在3.0T MR上,当铁浓度≤0.90 mg/mL时,R2和R2*值与铁浓度呈正相关(P＜0.05).结论:MRI定量测定体外不同铁浓度模型的可重复性好;在1.5T或3.0T MR各测量参数中,R2*值可准确定量反映体外铁浓度,且1.5T MR检测铁浓度范围宽于3.0T MR.