REF: updated usage and changed to oop
REF: updated usage and changed to oop

Former-commit-id: be12ea303ae40f267304c24739af632cb2fac274
Former-commit-id: a66f30395c838be471a9b606c499a055e78bc833
3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox