Purpose To achieve simultaneous T-1,(w)/proton density fat fraction (PDFF)/R2* mapping in abdomen within a single breadth-hold, and validate the accuracy using state-of-art measurement. Theory and Methods An optimized...
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Purpose To achieve simultaneous T-1,(w)/proton density fat fraction (PDFF)/R2* mapping in abdomen within a single breadth-hold, and validate the accuracy using state-of-art measurement. Theory and Methods An optimized multiple echo gradient echo (GRE) sequence with dual flip-angle acquisition was used to realize simultaneous water T-1 (T-1,(w))/PDFF/R2* quantification. A new method, referred to as "solving the fat-water ambiguity based on their T-1 difference" (SORT), was proposed to address the fat-water separation problem. This method was based on the finding that compared to the true solution, the wrong (or aliased) solution to fat-water separation problem showed extra dependency on the applied flip angle due to the T-1 difference between fat and water. The B1+ measurement sequence was applied to correct the B1+ inhomogeneity for T-1,(w) relaxometry. The 2D parallel imaging was incorporated to enable the acquisition within a single breath-hold in abdomen. Results The multi-parametric quantification results of the proposed method were consistent with the results of reference methods in phantom experiments (PDFF quantification: R-2 = 0.993, mean error 0.73%;T-1,(w) quantification: R-2 = 0.999, mean error 4.3%;R2* quantification: R-2 = 0.949, mean error 4.07 s(-1)). For volunteer studies, robust fat-water separation was achieved without evident fat-water swaps. Based on the accurate fat-water separation, simultaneous T-1,(w)/PDFF/R2* quantification was realized for whole liver within a single breath-hold. Conclusion The proposed method accurately quantified T-1,(w)/PDFF/R2* for the whole liver within a single breath-hold. This technique serves as a quantitative tool for disease management in patients with hepatic steatosis.
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