Repeatability and reproducibility of variable flip angle T₁ quantification in the prostate at 3 T

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Quantitative MRI
• Prostate Imaging

Background:

• Variable Flip Angle (VFA) imaging is a common method for estimating T1 relaxation in the prostate.
• However, VFA imaging's sensitivity to B1+ inhomogeneity can limit its repeatability and reproducibility.

Purpose of the Study:

• To evaluate the repeatability and reproducibility of prostate T1 estimation.
• To compare T1 estimation with and without B1+ correction methods.

Main Methods:

• Prospective study involving 21 volunteers scanned twice on two 3T MRI scanners.
• Two B1+ mapping techniques (RR-VFA and satTFL) were used for correction.
• Intrascanner repeatability and interscanner reproducibility of T1 maps were assessed using concordance correlation coefficients and Bland-Altman plots.

Main Results:

• Both RR-VFA-corrected T1 and satTFL-corrected T1 demonstrated higher intra- and interscanner correlation compared to uncorrected VFA T1.
• Bland-Altman analysis revealed narrower limits of agreement and a smaller T1 range for corrected T1 values.

Conclusions:

• Applying B1+ correction (RR-VFA or satTFL) to VFA T1 significantly improves T1 estimation repeatability and reproducibility.
• This correction offers potential for enhanced quantification of prostate dynamic contrast-enhanced MRI parameters.