Oregon Health and Science University, Department of Radiology, Portland, Oregon 97239, USA.
J Magn Reson Imaging. 2012 Nov;36(5):1248-55. doi: 10.1002/jmri.23705. Epub 2012 May 30.
To develop an image reconstruction algorithm that restores the signal polarity in a three-dimensional inversion-recovery (3D-IR) sequence used in delayed gadolinium-enhanced MRI of cartilage (dGEMRIC). This approach effectively doubles the dynamic range of data used for T1 curve fitting.
We applied this reconstruction algorithm to a 3D-IR TFE sequence used for T1 mapping, validated the technique in a phantom study, and performed T1-map calculations in postosteochondral allograft transplant (OAT) patients. In addition, we performed a signal simulation study to assess the algorithm's capability to reduce the number of inversion times used in the 3D-IR TFE sequence.
In comparison to a standard T1-mapping algorithm that uses the magnitude of the MRI signal, the proposed algorithm improves the reliability of T1 relaxation fits to the inversion-recovery three-parameter function. The signal simulation study shows that the number of TI inversion times can be reduced to as few as four, without compromising the accuracy of T1 calculations.
This algorithm can be applied to any 2D- or 3D-IR acquisition sequence used in conjunction with dGEMRIC. Application of the algorithm improves the reliability of T1 calculations and allows the number of TIs to be reduced, leading to shorter scan times in dGEMRIC.
开发一种图像重建算法，用于恢复用于软骨延迟钆增强 MRI（dGEMRIC）的三维反转恢复（3D-IR）序列中的信号极性。该方法有效地将用于 T1 曲线拟合的数据动态范围扩大了一倍。
我们将这种重建算法应用于用于 T1 映射的 3D-IR TFE 序列，在体模研究中验证了该技术，并在骨软骨同种异体移植（OAT）患者中进行了 T1 映射计算。此外，我们进行了信号模拟研究，以评估该算法在减少 3D-IR TFE 序列中反转时间数量方面的能力。
与使用 MRI 信号幅度的标准 T1 映射算法相比，所提出的算法提高了 T1 弛豫拟合到反转恢复三参数函数的可靠性。信号模拟研究表明，反转时间（TI）的数量可以减少到四个，而不会影响 T1 计算的准确性。
该算法可应用于与 dGEMRIC 联合使用的任何 2D 或 3D-IR 采集序列。应用该算法提高了 T1 计算的可靠性，并允许减少 TI 的数量，从而缩短 dGEMRIC 的扫描时间。
