Module r2star 

R2* and T2* mapping from multi-echo magnitude data

Provides R2* estimation using the ARLO (Auto-Regression on Linear Operations) algorithm for equi-spaced echo times, with a log-linear fallback for edge cases. T2* maps can be computed as the reciprocal of R2* via t2star_from_r2star.

Reference: Pei, M., et al. (2015). “Algorithm for fast monoexponential fitting based on Auto-Regression on Linear Operations (ARLO) of data.” Magnetic Resonance in Medicine, 73(2):843-850.

Functions

log_linear_fit 🔒

Log-linear R2* fit: log(S) = log(S0) - R2* * TE Solves via normal equations.

r2star_arlo

R2* mapping using ARLO for equi-spaced echo times (≥3 echoes).

t2star_from_r2star

Convert an R2* map (Hz) to a T2* map (seconds).

use_arlo

Check if echo times are approximately equi-spaced (suitable for ARLO).