the goal of ADNI is to validate biomarkers for AD clinical trials. No one uses multiecho mri for clinical trials, because the scans take so long and because the extra value of a multi echo scan has not been demonstrated for clinical trials. I do agree that relaxometry data would be interesting, but I've been following the field of MRI relaxometry for 30 years and I've never been particularly impressed with the added value (meaning what additional information do we have about the brain structure , fucntion, and disease mechanisms) of this approach
mike weiner