Accurate and precise in vivo liver 3D T₁ mapping at 3T

Area of Science:

• Medical Imaging
• Quantitative MRI
• Hepatology

Background:

• Clinical MRI scanners commonly use spoiled gradient-recalled echo sequences.
• Existing T1 mapping methods using these sequences can yield biased T1 estimates, particularly due to B1 inhomogeneities.
• Fat content in the liver can also confound T1 and T2 measurements.

Purpose of the Study:

• To develop a precise and accurate 3D liver T1 mapping technique.
• To create a scanner-agnostic method utilizing widely available MRI sequences.
• To establish a clinically feasible T1 measurement for hepatic fibro-inflammation assessment.

Main Methods:

• Developed a 3D T1 mapping method correcting for B1 inhomogeneities using a 2D gradient-echo double-angle approach.
• Integrated Dixon and fat saturation techniques to mitigate confounding effects of liver fat on T1 and T2 measurements.
• Validated the T1 and T2 mapping methods against gold standards using a phantom and conducted intra-/inter-repeatability studies in 10 healthy individuals at 3T.

Main Results:

• The 3D T1 mapping method demonstrated excellent agreement with gold standards, with a weighted root mean squared normalized error below 2.8%.
• In vivo, median T1 standard deviation was 31 ms (interquartile range [27, 39] ms), with a within-subject standard deviation of 21 ± 5 ms and a repeatability coefficient of 60 ms.
• Measured T1 values showed good agreement with MOLLI and SASHA T1 mapping methods, with average differences of 5%.

Conclusions:

• Accurate and precise 3D liver T1 measurements are achievable with the developed method.
• This technique offers a clinically feasible approach for T1 measurement.
• Wider adoption of T1 mapping as a marker for hepatic fibro-inflammation is facilitated by this advancement.