RLSQ: T₁, T₂, and ρ calculations, combining ratios and least squares

A method is proposed for calculating images of spin density rho and relaxation times T1, T2 from MR imaging sequences with the following characteristics: it avoids nonlinear iterative techniques and is consequently sufficiently fast to allow calculation of rho, T1, and T2 on a pixel by pixel basis routinely; it uses all available data simultaneously in an approximately optimal fashion. The method is applied to the combined SE + IR sequence but can be used for other acquisition schemes as well.