Tractography dissection variability: what happens when 42 groups dissect 14 white matter bundles on the same dataset?
Kurt G Schilling, Francois Rheault, Laurent Petit, Colin B Hansen, Vishwesh Nath, Fang-Cheng Yeh, Gabriel Girard, Muhamed Barakovic, Jonathan Rafael-Patino, Thomas Yu, Elda Fischi-Gomez, Marco Pizzolato, Riccardo Galbusera, Mario Ocampo-Pineda, Simona Schiavi, Erick J Canales-Rodriguez, Alessandro Daducci, Cristina Granziera, Giorgio Innocenti, Jean-Philippe Thiran, Laura Mancini, Stephen Wastling, Sirio Cocozza, Maria Petracca, Giuseppe Pontillo, Matteo Mancini, Sjoerd B Vos, Vejay N Vakharia, John S Duncan, Helena Melero, Lidia Manzanedo, Emilio Sanz-Morales, Angel Pena-Melian, Fernando Calamante, Arnaud Attye, Ryan P Cabeen, Laura Korobova, Arthur W Toga, Anupa Ambili Vijayakumari, Drew Parker, Ragini Verma, Ahmed Radwan, Stefan Sunaert, Louise Emsell, Alberto De Luca, Alexander Leemans, Claude Bajada, Hamied Haroon, Hojjatollah Azadbakht, Maxime Chamberland, Sila Genc, Chantal M.W. Tax, Ping-Hong Yeh, Rujirutana Srikanchana, Colin Mcknight, Joseph Y.M. Yang, Jian Chen, Claire E Kelly, Chun-Hung Yeh, Jerome Cochereau, Jerome J Maller, Thomas Welton, Fabien Almairac, Kiran K Seunarine, Chris A Clark, Fan Zhang, Nikos Makris, Alexandra Golby, Yogesh Rathi, Lauren J O’Donnell, Yihao Xia, Dogu Baran Aydogan, Yonggang Shi, Francisco Guerreiro Fernandes, Mathijs Raemaekers, Shaun Warrington, Stijn Michielse, Alonso Ramirez Manzanares, Luis Concha, Ramon Aranda, Mariano Rivera Meraz, Garikoitz Lerma-Usabiaga, Lucas Roitman, Lucius S Fekonja, Navona Calarco, Michael Joseph, Hajer Nakua, Aristotle N Voineskos, Philippe Karan, Gabrielle Grenier, Jon Haitz Legarreta, Nagesh Adluru, Veena A Nair, Vivek Prabhakaran, Andrew L Alexander, Koji Kamagata, Yuya Saito, Wataru Uchida, Christina Andica, Abe Masahiro, Roza G Bayrak, Claudia AM Gandini Wheeler-Kingshott, Egidio D’Angelo, Fulvia Palesi, Giovanni Savini, Nicolo Rolandi, Pamela Guevara, Josselin Houenou, Narciso Lopez-Lopez, Jean-Francois Mangin, Cyril Poupon, Claudio Roman, Andrea Vazquez, Chiara Maffei, Mavilde Arantes, Jose Paulo Andrade, Susana Maria Silva, Rajikha Raja, Vince D Calhoun, Eduardo Caverzasi, Simone Sacco, Michael Lauricella, Franco Pestilli, Daniel Bullock, Zhan Yang, Edith Brignoni-Perez, Catherine Lebel, Jess E Reynolds, Igor Nestrasil, Rene Labounek, Christophe Lenglet, Amy Paulson, Stefania Aulicka, Sarah Heilbronner, Katja Heuer, Adam W Anderson, Bennett A Landman, Maxime Descoteaux. “Tractography dissection variability: what happens when 42 groups dissect 14 white matter bundles on the same dataset?”. NeuroImage 242, 118451 (2021)
White matter bundle segmentation using diffusion MRI fiber tractography has become the method of choice to identify white matter fiber pathways in vivo in human brains. However, like other analyses of complex data, there is considerable variability in segmentation protocols and techniques. This can result in different reconstructions of the same intended white matter pathways, which directly affects tractography results, quantification, and interpretation. In this study, we aim to evaluate and quantify the variability that arises from different protocols for bundle segmentation. Through an open call to users of fiber tractography, including anatomists, clinicians, and algorithm developers, 42 independent teams were given processed sets of human whole-brain streamlines and asked to segment 14 white matter fascicles on six subjects. In total, we received 57 different bundle segmentation protocols, which enabled detailed volume-based and streamline-based analyses of agreement and disagreement among protocols for each fiber pathway. Results show that even when given the exact same sets of underlying streamlines, the variability across protocols for bundle segmentation is greater than all other sources of variability in the virtual dissection process, including variability within protocols and variability across subjects. In order to foster the use of tractography bundle dissection in routine clinical settings, and as a fundamental analytical tool, future endeavors must aim to resolve and reduce this heterogeneity. Although external validation is needed to verify the anatomical accuracy of bundle dissections, reducing heterogeneity is a step towards reproducible research and may be achieved through the use of standard nomenclature and definitions of white matter bundles and well-chosen constraints and decisions in the dissection process.
Keywords: Bundle segmentation; Dissection; Fiber pathways; Tractography; White matter.