Neuropathologist Bennett Omalu arguably sparked a revolution. Although previous scholars detected what appeared to be deleterious human brain change years or decades after exposure to repetitive concussive brain injuries (CBIs), in 2005 Dr. Omalu published more eloquent evidence suggesting that such exposure might provoke a somewhat homogeneous microscopic pathological profile. His timing was fortuitous: in the preceding decade, shaky scholarship had been invoked by a small cadre of researchers with the transparent agenda of demonstrating that American football rarely harms brains. The published possibility that, in fact, repetitive CBI often triggers persistent or delayed-onset neurodegeneration may eventually save many tens of thousands of years of productive human life. The problem: the observed brain changes are difficult to detect ante-mortem. Neuroimagers have stepped up to the challenge. This chapter introduces some of the evidence from in vivo brain imaging supporting the concerns raised by Dr. Omalu and his forebears.