Accurate field mapping in the presence of B0 inhomogeneities, applied to MR thermometry.
Accurate field mapping in the presence of B0 inhomogeneities, applied to MR thermometry.
复制标题
DOI：
10.1002/mrm.25338
复制
发表时间：
2015-06
影响因子：
3.3
通讯作者：
Madore, Bruno
中科院分区：
文献类型：
--
作者：
Mei, Chang-Sheng;Chu, Renxin;Hoge, W. Scott;Panych, Lawrence P.;Madore, Bruno
描述B0不均匀如何在质子共振频率(PRF)移位测温中引起误差，并纠正这些误差。对于PRF测温，通过使用与回波时间TE成比例的比例因子，将测量的相移转换为温度测量。然而，B0不均匀会使MR回波变形、扩散和平移，潜在地使成像对象内的真实回波时间在空间上发生变化，并呈现与规定TE值不同的值。提出了能够避免或纠正这种误差的捕获和重建方法。在超声波作用期间，在凝胶体模中进行测试，并使用适当的垫片以及故意引入的B0不均匀进行温度测量。通过所提出的方法，观察、描述和校正了由B0不均匀引起的误差。修正后的结果与用适当垫片得到的参考结果之间没有统计学差异，而温度升高误差超过10%则被修正了。该方法也被应用于腹部活体数据集。磁场变化会导致测量的场值产生误差，这是可以检测和校正的。该方法在PRF测温应用中得到了验证。
To describe how B0 inhomogeneities can cause errors in proton resonance frequency (PRF) shift thermometry, and to correct for these errors. With PRF thermometry, measured phase shifts are converted into temperature measurements through the use of a scaling factor proportional to the echo time, TE. However, B0 inhomogeneities can deform, spread, and translate MR echoes, potentially making the ‘true’ echo time vary spatially within the imaged object and take on values that differ from the prescribed TE value. Acquisition and reconstruction methods able to avoid or correct for such errors are presented. Tests were performed in a gel phantom during sonication, and temperature measurements were made with proper shimming as well as with intentionally-introduced B0 inhomogeneities. Errors caused by B0 inhomogeneities were observed, described, and corrected by the proposed methods. No statistical difference was found between the corrected results and the reference results obtained with proper shimming, while errors by more than 10% in temperature elevation were corrected for. The approach was also applied to an abdominal in vivo dataset. Field variations induce errors in measured field values, which can be detected and corrected. The approach was validated for a PRF thermometry application.
登录
查看更多内容
影响因子：
10.6
作者：
Hokland, Steffen L.;Pedersen, Michael;Moonen, Chrit T. W.
通讯作者：
Moonen, Chrit T. W.
影响因子：
3.3
作者：
Baudrexel, Simon;Volz, Steffen;Deichmann, Ralf
通讯作者：
Deichmann, Ralf
影响因子：
3.8
作者：
McDannold, Nathan;Hynynen, Kullervo
通讯作者：
Hynynen, Kullervo
影响因子：
3.5
作者：
Gorny, K. R.;Hangiandreou, N. J.;Felmlee, J. P.
通讯作者：
Felmlee, J. P.
影响因子：
4.4
作者：
Lepetit-Coiffe, Matthieu;Quesson, Bruno;Trillaud, Herve
通讯作者：
Trillaud, Herve