Confounder‐corrected<scp><i>T</i><sub>1</sub></scp>mapping in the liver through simultaneous estimation of<scp><i>T</i><sub>1</sub></scp>,<scp>PDFF</scp>, R2*, and B1+ in a single breath‐hold acquisition
Nathan Roberts, Daiki Tamada, Yavuz Muslu, Diego Hernando, Scott B. Reeder
Abstract
Purpose Quantitative volumetric T 1 mapping in the liver has the potential to aid in the detection, diagnosis, and quantification of liver fibrosis, inflammation, and spatially resolved liver function. However, accurate measurement of hepatic T 1 is confounded by the presence of fat and inhomogeneous excitation. Furthermore, scan time constraints related to respiratory motion require tradeoffs of reduced volumetric coverage and/or increased acquisition time. This work presents a novel 3D acquisition and estimation method for confounder‐corrected T 1 measurement over the entire liver within a single breath‐hold through simultaneous estimation of T 1 , fat and . Theory and Methods The proposed method combines chemical shift encoded MRI and variable flip angle MRI with a mapping technique to enable confounder‐corrected T 1 mapping. The method was evaluated theoretically and demonstrated in both phantom and in vivo acquisitions at 1.5 and 3.0T. At 1.5T, the method was evaluated both pre‐ and post‐ contrast enhancement in healthy volunteers. Results The proposed method demonstrated excellent linear agreement with reference inversion‐recovery spin‐echo based T 1 in phantom acquisitions at both 1.5 and 3.0T, with minimal bias (5.2 and 45 ms, respectively) over T 1 ranging from 200–1200 ms. In vivo results were in general agreement with reference saturation‐recovery based 2D T 1 maps (SMART 1 Map, GE Healthcare). Conclusion The proposed 3D T 1 mapping method accounts for fat and confounders through simultaneous estimation of T 1 , , PDFF and . It demonstrates strong linear agreement with reference T 1 measurements, with low bias and high precision, and can achieve full liver coverage in a single breath‐hold.