Absolute MR Thermometry Using Time-Domain Analysis of Multi-Gradient-Echo Magnitude Images
Absolute MR Thermometry Using Time-Domain Analysis of Multi-Gradient-Echo Magnitude Images
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DOI：
10.1002/mrm.22429
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发表时间：
2010-07-01
影响因子：
3.3
通讯作者：
Bartels, Lambertus W.
中科院分区：
文献类型：
--
作者：
Sprinkhuizen, Sara M.;Bakker, Chris J. G.;Bartels, Lambertus W.
MRI允许对含有两种光谱共振的物质进行绝对温度测量，其中频率差f(T)与绝对温度有关。这种频率差可以从光谱数据中提取出来。多梯度回波序列是一种基于图像的磁共振技术，它允许在高时间和空间分辨率下获取光谱数据。在这项工作中，进一步发展了多梯度回波序列在磁共振测温中的应用。利用多梯度回波信号幅度的时域分析，探讨了将多梯度回波数据后处理成绝对温度图的可能性。在这种方法中，f(T)是直接输出参数，而不是从单独找到的频率间接计算f(T)。体外实验为从多梯度回波量级图像的时域分析中检索绝对温度图提供了概念证明。结果表明，该技术对场漂移和局部场扰动都不敏感。此外，还进行了离体骨髓实验，以脂肪共振作为绝对温度测绘的参考。结果表明，基于时域幅度信号的后处理可以确定骨髓中的f(T)。中华医学杂志，2010,34(4):379 - 379。(C) 2010 Wiley-Liss, Inc。
MRI allows for absolute temperature measurements in substances containing two spectral resonances of which the frequency difference Delta f(T) is related to absolute temperature. This frequency difference can be extracted from spectroscopic data. An image-based MR technique that allows for the acquisition of spectroscopic data at high temporal and spatial resolution is the multi-gradient-echo sequence. In this work, the application of the multi-gradient-echo sequence for MR thermometry purposes was further developed. We investigated the possibility of postprocessing the multi-gradient-echo data into absolute temperature maps, using time-domain analysis of the magnitude of the multi-gradient-echo signals. In this approach, instead of an indirect computation of Delta f(T) from separately found frequencies, Delta f(T) is a direct output parameter. In vitro experiments were performed to provide proof of concept for retrieving absolute temperature maps from the time-domain analysis of multi-gradient-echo magnitude images. It is shown that this technique is insensitive to both field drift and local field disturbances. Furthermore, ex vivo bone marrow experiments were performed, using the fat resonance as a reference for absolute temperature mapping. It is shown that the postprocessing based on the magnitude signal in the time domain allows for the determination of Delta f(T) in bone marrow. Magn Reson Med 64:239-248, 2010. (C) 2010 Wiley-Liss, Inc.