Test–retest reliability and concurrent validity of in vivo myelin content indices: Myelin water fraction and calibrated T₁w/T₂w image ratio

In an age‐heterogeneous sample of healthy adults, we examined test–retest reliability (with and without participant repositioning) of two popular MRI methods of estimating myelin content: modeling the short spin–spin (T 2 ) relaxation component of multi‐echo imaging data and computing the ratio of T 1 ‐weighted and T 2 ‐weighted images (T 1 w/T 2 w). Taking the myelin water fraction (MWF) index of myelin content derived from the multi‐component...