REF: remove temp file creation to improve computation time
REF: remove temp file creation to improve computation time

Former-commit-id: 74af548cbacef33f70f47877c115028d81b360f5
Former-commit-id: 2891ea2e6484e113a3e4726dc8537a8502e68c2b
3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox