TL;DR: Brain morphometry at 64mT (= 0.064T) is very much feasible. Perhaps most interesting is the fact that the dataset -> ~ T1w & T2w scans x (4 resolutions x 2 Hyperfine Swoop 64 mT scanners + GE 3T scanner) x 23 adult participants = 390 scans -> is openly available: openneuro.org/datasets/ds0...
