Myocardial T2* measurement in iron-overloaded thalassemia:: An ex vivo study to investigate optimal methods of quantification
Myocardial T2* measurement in iron-overloaded thalassemia:: An ex vivo study to investigate optimal methods of quantification
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DOI：
10.1002/mrm.21625
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发表时间：
2008-08-01
影响因子：
3.3
通讯作者：
Firmin, David N.
中科院分区：
文献类型：
--
作者：
He, Taigang;Gatehouse, Peter D.;Firmin, David N.
心肌 T-2* 测量越来越多地用于铁定量，以评估地中海贫血患者心脏并发症的风险。在这项研究中，我们对铁超载离体心脏上的噪声影响以及不同的曲线拟合模型进行了评估，以确定 T-2* 测量的最佳方法，并帮助了解影响再现性和准确性的问题。使用不同数量的激励采集梯度多回波短轴图像，以生成不同的信噪比 (SNR) 图像。实施了噪声校正方法；比较了线性和非线性曲线拟合算法，并评估了不同的曲线拟合模型（单指数、截断、基线减法和偏移）。这项研究表明，离体心脏中的 T-2* 衰减曲线可以通过单指数模型进行拟合，并且通过适当的噪声校正可以获得准确的 T-2* 测量。对于 MRI 噪声，T-2* 通常会因包含后期低 SNR 数据点而被高估，但会因偏移或基线减法模型而被低估，而这实际上是等效的。在这种情况下，截断模型被证明是可重复的并且比其他模型更准确。研究还表明，在T-2*曲线拟合中非线性算法是首选。
Myocardial T-2* measurement has been increasingly used for iron quantification to assess the risk of cardiac complications in thalassemia patients. In this study the noise effects were evaluated along with different curve-fitting models on an iron overloaded ex vivo heart in order to determine the optimal method of T-2* measurement and to help understand issues affecting reproducibility and accuracy. Gradient multiecho short axis Images were acquired with differing numbers of excitations to generate varying signal-to-noise ratio (SNR) images. A noise correction method was implemented; linear and nonlinear curve-fitting algorithms were compared and different curve-fitting models (monoexponential, truncation, baseline subtraction, and offset) were evaluated. This study suggests that the T-2* decay curve in an ex vivo heart can be fitted by a monoexponential model and accurate T-2* measurements can be obtained with proper noise correction. With MRI noise, T-2* is generally overestimated by including late low SNR data points, but underestimated by the offset or baseline subtraction models, which are in fact equivalent. In this situation the truncation model proves to be reproducible and more accurate than the other models. The study also shows that the nonlinear algorithm is preferred in T-2* curve fitting.