Past challenges in fiber tractography. Detailed description of data, ground truth, and evaluation are described in the text. (A) FiberCup Phantom pathways with 16 ground truth bundles [21]. (B) Eight example CST reconstructions from the DTI Challenge [23]. (C) Synthetic fiber fields from the HARDI Reconstruction Challenge [26]. (D) Phantomas [27] dataset for Tractometer evaluation [28]. (E) Creation of simulated in vivo human dataset for the ISMRM Tractography Challenge [29]. (F) Example submissions from the TraCED Reproducibility Challenge for two white matter pathways. (G) 3D-VoTEM ground truths defined on the macaque, squirrel monkey, and phantom (from left to right). Reproduced and modified from Fillard et al. (2011), and Schilling et al. (2018) with permission from Elsevier; from Pujol et al. (2105) with permission from Wiley; from Daducci et al. (2014) with permission from IEEE, and from Maier-Hein et al. (2017) under a Create Commons license from Nature Publishing Group.