BUG: fix bug when computing CSA (due to resolution correction)
BUG: fix bug when computing CSA (due to resolution correction)

Former-commit-id: 039d012bd12739a50ccccfaa21d3d7a8456e38ec
Former-commit-id: 1597470933d124a39c60259b0041e4f717f8fa76
3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox