Dual-pathway multi-echo sequence for simultaneous frequency and T2 mapping

作者：Cheng, Cheng-Chieh; Mei, Chang-Sheng^*; Duryea, Jeffrey; Chung, Hsiao-Wen; Chao, Tzu-Cheng; Panych, Lawrence P.; Madore, Bruno

来源：Journal of Magnetic Resonance, 2016, 265: 177-187.

DOI：10.1016/j.jmr.2016.01.019

• Quantitative imaging
• Field mapping
• T-2 mapping
• MR thermometry
• Susceptibility-weighted imaging
• Osteoarthritis
• Multi-pathway imaging

Purpose: To present a dual-pathway multi-echo steady state sequence and reconstruction algorithm to capture T-2, T-2* and field map information. Methods: Typically, pulse sequences based on spin echoes are needed for T-2 mapping while gradient echoes are needed for field mapping, making it difficult to jointly acquire both types of information. A dual-pathway multi-echo pulse sequence is employed here to generate T-2 and field maps from the same acquired data. The approach might be used, for example, to obtain both thermometry and tissue damage information during thermal therapies, or susceptibility and T-2 information from a same head scan, or to generate bonus T-2 maps during a knee scan. Results: Quantitative T-2, T-2* and field maps were generated in gel phantoms, ex vivo bovine muscle, and twelve volunteers. T-2 results were validated against a spin-echo reference standard: A linear regression based on ROI analysis in phantoms provided dose agreement (slope/R-2= 0.99/0.998). A pixel-wise in vivo Bland Altman analysis of R-2 =1/T-2 showed a bias of 0.034 Hz (about 0.3%), as averaged over four volunteers. Ex vivo results, with and without motion, suggested that tissue damage detection based on T-2 rather than temperature-dose measurements might prove more robust to motion. Conclusion: T-2, 31 and field maps were obtained simultaneously, from the same datasets, in thermometry, susceptibility-weighted imaging and knee-imaging contexts.

• 出版日期2016-4
• 单位苏州大学