La linea es fina, demasiado para mi gusto, dejo una referencia
http://martinfowler.com/articles/injection.html y cito:
Cita: As a result I think we need a more specific name for this pattern. Inversion of Control is too generic a term, and thus people find it confusing. As a result with a lot of discussion with various IoC advocates we settled on the name Dependency Injection.
IMO, IoC es una técnica o practica y DI es una forma de conseguirlo al igual que lo es ServiceLocator(para algunos anti-pattern).
Saludos.