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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0~5.0mg/mL。另一组铁浓度范围为0~1.0mg/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、T2map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≤1.5mg/mL时,T1WISNR、R2与铁浓度呈显著性正相关(P<0.05)。R2*则在铁浓度≤2.5mg/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≤0.90mg/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。
OBJECTIVE: To investigate the reliability of MRI in quantitative determination of iron concentration in vitro and to compare the accuracy of quantitative determination of iron concentration in vitro by 1.5T and 3.0T MR. Methods: Two groups of different iron concentration in vitro models were made. One group of iron concentration ranged from 0 to 5.0 mg / mL. Another set of iron concentrations ranged from 0 to 1.0 mg / mL. The two iron concentration models were scanned on 1.5T and 3.0T MR respectively. The scan sequence includes short axis FSE / T1WI, FRFSE / T2WI, T2map and T2 * map. Evaluation measures include T1WI and T2WI signal to noise, T2, R2, T2 * and R2 * values. Evaluation of the consistency of indicators using group correlation coefficient analysis. The relationship between iron concentration and T1WI signal-to-noise ratio, T2WI signal to noise ratio, T2, R2, T2 * and R2 * values was analyzed using Pearson correlation analysis. Results: The in-group correlation coefficients between two investigators for the consistency of T1WI signal-to-noise ratio, T2WI signal-to-noise ratio, T2, R2, T2 * and R2 * ). T2WI signal-to-noise ratio, T2 and T2 * values were non-linearly correlated with iron concentrations at 1.5T and 3.0T MR. At 1.5T MR, there was a significant positive correlation between T1WISNR, R2 and iron concentration (P <0.05) when iron concentration was less than 1.5mg / mL. R2 * showed a significantly positive linear correlation with iron concentration (P <0.001) at iron concentrations <2.5 mg / mL. On the 3.0 T MR, R2 and R2 * values positively correlated with iron concentration (P <0.05) when iron concentration was less than 0.90 mg / mL. CONCLUSION: The reproducibility of MRI in quantitative determination of iron concentration in vitro is good. R2 * can accurately reflect the concentration of iron in 1.5T or 3.0T MR, and the range of 1.5T MR iron concentration is wider than 3.0 T MR.