Stack Alignment Transform for Misalignment Correction in Cardiac MR Cine Series

Stack misalignment in cardiac MR cine series distorts the correct appearance of anatomical features and reduces the reproducibility of volumetric measurements computed for diagnostic purposes. This paper describes a method for correction of stack misalignment in cardiac MR series. Our method involves registration against a reference volume and features a prominent enhancement designed to circumvent the weaknesses associated with slice-to-volume registration. The core of the presented method is a custom stack alignment transform which parametrises the in-plane movement for all slices independently of each other; at the same time the image similarity metric for every optimisation iteration is calculated on the whole stack with all slice correction parameters contributing to the result. The method was evaluated on 50 clinical datasets with a 100 simulated optimisation runs for every dataset. The results show that on average the method is able to recover alignment parameters with sub-voxel accuracy.