Benkhedah Nadia, Hoffmann Stefan H, Biller Armin, Nagel Armin M
German Cancer Research Center (DKFZ), Division of Medical Physics in Radiology, Heidelberg, Germany.
University Hospital Heidelberg, Department of Neuroradiology, Heidelberg, Germany.
Magn Reson Med. 2016 Feb;75(2):527-36. doi: 10.1002/mrm.25572. Epub 2015 Mar 28.
The aim was to optimally combine multichannel coil array data in sodium ((23) Na) MRI.
(23) Na MRI was conducted on a 3 Tesla MR system using a 30-channel head receive coil array. The parameters used for the adaptive combination (ADC) reconstruction of the low signal-to-noise ratio (SNR) dataset have been optimized by finding the maximum mean SNR. A pseudo multiple-replica approach has been used to obtain SNR maps of the combined images. To prove reproducibility of the combination algorithm, the procedure was repeated for several measurements.
For low SNR data, sum-of-squares (SOS) reconstruction leads to high background noise and a signal bias in the imaged object. The ADC reconstruction clearly reduces noise in the image and leads to an increase of the mean SNR in the range of 8% to 50%, compared to weighted SOS depending on the absolute SNR of the image. The evaluation of the effects of different noise scans showed that a small number of projections can be used to estimate noise statistics of the coil array without substantially decreasing the resulting SNR.
(23) Na MRI can be markedly improved by using a 30-channel receive array and ADC reconstruction. The ADC reconstruction showed robust results for all measurements without the need for sensitivity maps.
旨在优化钠（²³Na）磁共振成像（MRI）中多通道线圈阵列数据的组合。
在一台3特斯拉MR系统上使用30通道头部接收线圈阵列进行²³Na MRI检查。通过找到最大平均信噪比，对低信噪比（SNR）数据集的自适应组合（ADC）重建所使用的参数进行了优化。已采用伪多副本方法来获取组合图像的SNR图。为证明组合算法的可重复性，对多次测量重复了该过程。
对于低SNR数据，平方和（SOS）重建会导致高背景噪声以及成像对象中的信号偏差。与根据图像绝对SNR的加权SOS相比，ADC重建明显降低了图像中的噪声，并使平均SNR提高了8%至50%。对不同噪声扫描效果的评估表明，少量投影可用于估计线圈阵列的噪声统计信息，而不会大幅降低所得SNR。
使用30通道接收阵列和ADC重建可显著改善²³Na MRI。ADC重建对所有测量均显示出稳健的结果，无需灵敏度图。
