Dual flip angle liver T1 mapping with B1 correction at 3 T - In vitro and in vivo evaluation

Area of Science:

• Radiology and Medical Imaging
• Quantitative MRI
• Hepatobiliary Imaging

Background:

• Accurate T1 mapping is crucial for liver disease assessment.
• Dual flip angle (DFA) T1 mapping offers a rapid approach for quantitative MRI.
• Optimizing region of interest (ROI) selection is key for reliable in vivo measurements.

Purpose of the Study:

• To evaluate the in vitro precision and linearity of 3D whole-liver dual flip angle (DFA) T1 mapping.
• To compare various circular ROI sampling strategies for in vivo liver T1 measurements.

Main Methods:

• 3D steady-state spoiled gradient echo with DFA was used at 3T.
• In vitro validation against inversion recovery turbo spin echo (IRTSE) reference T1 values.
• In vivo study in 30 patients, assessing manual segmentation and 4 ROI strategies for inter-reader agreement.

Main Results:

• In vitro DFA T1 measurements demonstrated strong linearity (R²=0.9912) with a 16.33% overestimation versus IRTSE.
• In vivo, larger ROI areas improved inter-reader agreement (R² increased to 0.9601) and agreement with manual segmentation.
• Increasing ROI size consistently enhanced accuracy and reduced variability for both readers.

Conclusions:

• DFA T1 mapping provides a highly linear and accurate method for liver T1 quantification.
• Larger ROI selection in vivo significantly improves measurement reliability and consistency.
• DFA T1 mapping is a promising technique for quantitative liver MRI.