MR imaging differentiation of Fe2+ and Fe3+ based on relaxation and magnetic susceptibility properties
MR imaging differentiation of Fe2+ and Fe3+ based on relaxation and magnetic susceptibility properties
复制标题
DOI：
10.1007/s00234-017-1813-3
复制
发表时间：
2017-04-01
期刊：
影响因子：
2.8
通讯作者：
Ertl-Wagner, Birgit
中科院分区：
文献类型：
--
作者：
Dietrich, Olaf;Levin, Johannes;Ertl-Wagner, Birgit
目的探讨亚铁(Fe2+)和铁离子(Fe3+)的磁共振成像行为，以期建立一种无创的定量鉴别这两种铁离子的方法。方法在3T下对21个样品进行磁共振成像，其中21个样品分别加入不同浓度的铁和三氯化铁溶液(0~10 mmoL/L)。T(2)*和定量磁化率测量均使用具有8个回声的多回声破坏梯度回波脉冲序列。横向弛豫速率R(2)*=1/T(2)*由每个样本的平均信号通过非线性指数拟合法确定。通过将单位偶极子响应的空间卷积与测量的内场图进行拟合，计算了样品在相位展开和背景场去除后的磁化率CHI。结果不同浓度Fe3+和Fe2+松弛速率的线性斜率分别为(12.5+/-0.4)S(-1)/(mol/L)和(0.77+/-0.0 9)S(-1)/(mmo1/L)(P<0.0 5)。Z检验P<；0.0001)。磁化率的线性斜率分别为(0.088+/-0.003)ppm/(mmo1/L)和(0.079+/-0.006)ppm/(mmo1/L)。个体比值Delta R(2)*/Delta CHI除1例外均大于40 S(-1)/ppm，其余均小于20 S(-1)/ppm。结论亚铁和铁离子在磁共振成像中表现出明显不同的松弛行为，但易感性相似。这些性质可用于区分铁样和铁样。
Purpose The aim of this study is to evaluate the MR imaging behavior of ferrous (Fe2+) and ferric (Fe3+) iron ions in order to develop a noninvasive technique to quantitatively differentiate between both forms of iron.Methods MRI was performed at 3 T in a phantom consisting of 21 samples with different concentrations of ferrous and ferric chloride solutions (between 0 and 10 mmol/L). A multi-echo spoiled gradient-echo pulse sequence with eight echoes was used for both T (2)* and quantitative susceptibility measurements. The transverse relaxation rate, R (2)* = 1/T (2)*, was determined by nonlinear exponential fitting based on the mean signals in each sample. The susceptibilities, chi, of the samples were calculated after phase unwrapping and background field removal by fitting the spatial convolution of a unit dipole response to the measured internal field map. Relaxation rate changes, Delta R (2)*(c (Fe)), and susceptibility changes, Delta chi(c (Fe)), their linear slopes, as well as the ratios Delta R (2)*(c (Fe)) / Delta chi(c (Fe)) were determined for all concentrations.Results The linear slopes of the relaxation rate were (12.5 +/- 0.4) s(-1)/(mmol/L) for Fe3+ and (0.77 +/- 0.09) s(-1)/(mmol/L) for Fe2+ (significantly different, z test P < 0.0001). The linear slopes of the susceptibility were (0.088 +/- 0.003) ppm/(mmol/L) for Fe3+ and (0.079 +/- 0.006) ppm/(mmol/L) for Fe2+. The individual ratios Delta R (2)*/Delta chi were greater than 40 s(-1)/ppm for all samples with ferric solution and lower than 20 s(-1)/ppm for all but one of the samples with ferrous solution.Conclusion Ferrous and ferric iron ions show significantly different relaxation behaviors in MRI but similar susceptibility patterns. These properties can be used to differentiate ferrous and ferric samples.