Slice alignment approaches are described for short axis cardiac magnetic resonance cine slice stacks, which do not require additional scans, such as long axis scans or full 3D scans, and which are able to deal with cardiac structures having complex shapes. Both approaches do not need contours to follow a quadratic curvature function, and are well suitable for the purpose of obtaining a segmentation of a cardiac structure using a deformable surface model. Namely, such a deformable surface model is unable, but also not desired, to fully adapt to the 'zig-zag'-shaped pattern in the boundary of the cardiac structure due to the slice misalignment. Having removed or reduced the misalignment between image slices, such a deformable surface model may better adapt to the cardiac structure in the image data and thereby provide a better segmentation of the cardiac structure.