Analytical Dual Flip Angle R1 Calculation Outside the Small-Angle Regime.

ABSTRACT:

Purpose

To evaluate a new analytical estimator for R1 and apparent proton density ( A$$ A $$ ) from short-TR dual flip angle data which does not rely on the small flip angle approximation and can thus be applied to a broader range of data, especially where relatively large flip angles are needed to achieve sufficient T1-weighting for R1 estimation.

Theory and methods

A rational approximation of the Ernst equation was derived for small R1·TR$$ \mathrm{R}1\cdotp \mathrm{TR} $$ and rearranged to give analytical estimators of R1 and A$$ A $$ from dual flip angle data. Unlike previously used analytical estimators, this method relies neither on the flip angles being small nor the two TRs being equal or integer multiples of each other. R1 and A$$ A $$ estimated using the novel meth

SUBMITTER: Edwards LJ 

PROVIDER: S-EPMC12850634 | biostudies-literature | 2026 Apr

REPOSITORIES: biostudies-literature