1. A CT system comprising: a gantry having a rotatable base and having an opening for receiving an object to be scanned; an x-ray source; a CT detector; and a computer comprising processing circuitry configured to: detect a mis-registration at a slab boundary between a first slab and a second slab of a reconstructed image, wherein the first slab is a reconstructed image of a plurality of slices of imaging data obtained during a first heartbeat, and the second slab is a reconstructed image of a plurality of slices of imaging data obtained during a second heartbeat; quantify an amount of mis-registration at the slab boundary by quantifying a vector in an axial plane at the slab boundary; and adjust the reconstructed image at the slab boundary based on the quantification by applying a compensation vector to a set of image slices on both sides of the slab boundary, wherein a weight applied to the compensation vector decreases as distance from the slab boundary increases such that effective compensation decreases away from the slab boundary.