A computed tomography system (10, 160) comprising: a rotatable gantry (12, 162) having an opening (48, 164) for receiving an object (24, 166) to be scanned; an x-ray source (14, 170) coupled to the gantry (12, 162) and configured to project x-rays through the opening (48, 164); a generator configured to energize the x-ray source (14, 170) to generate the x-rays; a detector (16, 168) having pixels therein, the detector (16, 168) attached to the gantry (12, 162) and positioned to receive the x-rays; and a computer programmed to: acquire CT data representative of an object (24, 166); determine (112, 136, 146) a first subset of the CT data during a rotation of the gantry; determine (114, 140, 150) a second subset of the CT data during said rotation of the gantry; determine a difference between the first and second subsets of the CT data to identify a region in the object, wherein the region represents a region where motion occurred within the object during acquisition of the CT data; characterised in that the computer is further programmed to update (126, 156) image data reconstructed from a first portion of the first subset of the CT data and corresponding to the region; and reconstruct (128, 157) an image based on the updated image data and non-updated image data, wherein the non-updated image data is reconstructed from a second portion of the first subset of the CT data, wherein said second portion represents a region where substantially no motion occurred within the object during acquisition of the CT data. a rotatable gantry (12, 162) having an opening (48, 164) for receiving an object (24, 166) to be scanned; an x-ray source (14, 170) coupled to the gantry (12, 162) and configured to project x-rays through the opening (48, 164); a generator configured to energize the x-ray source (14, 170) to generate the x-rays; a detector (16, 168) having pixels therein, the detector (16, 168) attached to the gantry (12, 162) and positioned to receive the x-rays; and a computer programmed to: acquire CT data representative of an object (24, 166); determine (112, 136, 146) a first subset of the CT data during a rotation of the gantry; determine (114, 140, 150) a second subset of the CT data during said rotation of the gantry; determine a difference between the first and second subsets of the CT data to identify a region in the object, wherein the region represents a region where motion occurred within the object during acquisition of the CT data; characterised in that the computer is further programmed to update (126, 156) image data reconstructed from a first portion of the first subset of the CT data and corresponding to the region; and reconstruct (128, 157) an image based on the updated image data and non-updated image data, wherein the non-updated image data is reconstructed from a second portion of the first subset of the CT data, wherein said second portion represents a region where substantially no motion occurred within the object during acquisition of the CT data. acquire CT data representative of an object (24, 166); determine (112, 136, 146) a first subset of the CT data during a rotation of the gantry; determine (114, 140, 150) a second subset of the CT data during said rotation of the gantry; determine a difference between the first and second subsets of the CT data to identify a region in the object, wherein the region represents a region where motion occurred within the object during acquisition of the CT data; characterised in that the computer is further programmed to update (126, 156) image data reconstructed from a first portion of the first subset of the CT data and corresponding to the region; and reconstruct (128, 157) an image based on the updated image data and non-updated image data, wherein the non-updated image data is reconstructed from a second portion of the first subset of the CT data, wherein said second portion represents a region where substantially no motion occurred within the object during acquisition of the CT data.