Liver Methylene Fraction by Dual- and Triple-Echo Gradient-Echo Imaging at 3.0T: Correlation With Proton MR Spectroscopy and Estimation of Robustness After SPIO Administration
Liver Methylene Fraction by Dual- and Triple-Echo Gradient-Echo Imaging at 3.0T: Correlation With Proton MR Spectroscopy and Estimation of Robustness After SPIO Administration
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DOI：
10.1002/jmri.22390
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发表时间：
2011-01-01
影响因子：
4.4
通讯作者：
Krause, Denis
中科院分区：
文献类型：
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作者：
Guiu, Boris;Petit, Jean-Michel;Krause, Denis
目的：为了评估双回波和三回波梯度回波双/三回波GRE序列的脂肪-脂肪干扰效应导致的肝脏亚甲基分数（LMF）的系统误差，并测试铁过载后这些序列的稳健性。材料和方法：应用3.0T H-1磁共振波谱仪对40例2型糖尿病患者进行LMF测定（针对T1和T2衰减校正）作为参考标准，并通过具有20度和60度翻转角（α）的四个双/三重GRE序列测量肝脏脂肪分数（%脂肪），针对T1恢复校正。在8名患者注射氧化铁后重复相同的四个序列。根据线性回归（光谱LMF值与双重/三重GRE %脂肪值）确定系统误差的校正。结果：脂肪-脂肪干扰效应产生的相对系统误差接近10%，T2* 衰减产生的绝对系统误差为1.9%~ 4.2%。当比较ferumoxide前后时，α = 20度和α = 60度的双回波成像，即使经过校正，也显示绝对差异为7.23% [2.81%-10.25%]（P = 0.0117）和5.65% [1.89%-8.216.8%]（P = 0.0117）;相比之下，只有1.17% [0.08%-2.83%]（P = 0.0251）和1.15% [0.37%-2.73%]（P = 0.2626），三回波成像，α = 20度和α = 60度。在超顺磁性氧化铁（SPIO）给药后，针对T1恢复和脂肪-脂肪干扰效应校正α = 60度的三重回波成像是稳健的，并且可以可靠地量化LMF。
Purpose: To assess the systematic errors in liver methylene fraction (LMF) resulting from fat-fat interference effects with dual- and triple-echo gradient-recalled-echo Dual/Triple GRE) sequences and to test the robustness of these sequences after iron overloading.Materials and Methods: Forty type-2 diabetic patients underwent LMF measurement by 3.0T H-1 magnetic resonance spectroscopy (corrected for T1 and T2 decays) as the reference standard and liver fat fraction (%Fat) measurement by four Dual/Triple GRE sequences with 20 degrees and 60 degrees flip angle (alpha), corrected for T1 recovery. The same four sequences were repeated in eight patients after ferumoxide injection. Corrections for systematic errors were determined from the linear regressions (spectroscopy LMF values over Dual/Triple GRE %Fat values). Robustness was tested using Wilcoxon's signed-rank test.Results: Fat-fat interference effects produced a similar to 10% relative systematic error and T2* decay produced a 1.9%-4.2% absolute systematic error in LMF. When comparing before and after ferumoxide, dual-echo imaging with alpha = 20 degrees and alpha = 60 degrees, even when corrected, showed absolute differences of 7.23% [2.81%-10.25%] (P = 0.0117) and 5.65% [1.89%-8.216.8%] (P = 0.0117), respectively; compared to only 1.17% [0.08%-2.83%] (P = 0.0251) and 1.15% [0.37%-2.73%] (P = 0.2626) with triple-echo imaging and alpha = 20 degrees and alpha = 60 degrees, respectively.Conclusion: Triple-echo imaging with alpha = 60 degrees corrected for both T1 recovery and fat-fat interference effects is robust after superparamagnetic iron oxide (SPIO) administration and can reliably quantify LMF.