科研之友
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摘要
PurposeTo describe how B-0 inhomogeneities can cause errors in proton resonance frequency (PRF) shift thermometry, and to correct for these errors. MethodsWith PRF thermometry, measured phase shifts are converted into temperature measurements through the use of a scaling factor proportional to the echo time, TE. However, B-0 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. ResultsTests were performed in a gel phantom during sonication, and temperature measurements were made with proper shimming as well as with intentionally introduced B-0 inhomogeneities. Errors caused by B-0 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. ConclusionField variations induce errors in measured field values, which can be detected and corrected. The approach was validated for a PRF thermometry application. Magn Reson Med 73:2142-2151, 2015.
- 出版日期2015-6
- 单位苏州大学
