Deformation analysis of 3D tagged cardiac images using an optical flow method

Background. this study proposes and validates a method of measuring 3d strain in myocardium using a 3d cardiovascular magnetic resonance (cmr) tissue-tagging sequence and a 3d optical flow method (ofm). methods. initially,a 3d tag mr sequence was developed and the parameters of the sequence and 3d ofm were optimized using phantom images with simulated deformation. this method then was validated in-vivo and utilized to quantify normal sheep left ventricular functions. results. optimizing imaging and ofm parameters in the phantom study produced sub-pixel root-mean square error (rms) between the estimated and known displacements in the x (rmsx= 0.62 pixels (0.43 mm)),y (rmsy = 0.64 pixels (0.45 mm)) and z (rmsz = 0.68 pixels (1 mm)) direction,respectively. in-vivo validation demonstrated excellent correlation between the displacement measured by manually tracking tag intersections and that generated by 3d ofm (r 0.98). technique performance was maintained even with 20% gaussian noise added to the phantom images. furthermore,3d tracking of 3d cardiac motions resulted in a 51% decrease in in-plane tracking error as compared to 2d tracking. the in-vivo function studies showed that maximum wall thickening was greatest in the lateral wall,and increased from both apex and base towards the mid-ventricular region. regional deformation patterns are in agreement with previous studies on lv function. conclusion. a novel method was developed to measure 3d lv wall deformation rapidly with high in-plane and through-plane resolution from one 3d cine acquisition. © 2010 xu et al; licensee biomed central ltd.