Animations to illustrate the performance of different registration software applied to dynamic free-breathing lung oxygen-enhanced MRI (OE-MRI) data. NiftyReg and ANTs registration software were implemented.See the Animations Captions PDF document for detailed descriptions of the registered image series.NiftyReg registration:M. Modat et al. “Fast free-form deformation using graphics processing units". In: Computer Methods and Programs in Biomedicine 98.3 (2010), pp. 278-284. ISSN: 01692607. DOI: 10.1016/j.cmpb.2009.09.002.M. Modat et al. “Parametric non-rigid registration using a stationary velocity field". In: 2012 IEEE Workshop on Mathematical Methods in Biomedical Image Analysis. 2012, pp. 145-150. DOI: 10.1109/MMBIA.2012.6164745.Details of the NiftyReg registration implementation:Multi-resolution levels3Control point grid spacing3 voxels, 14.1 mm final spacingSimilarity metricLocally normalised cross-correlationPenalty terms and weightsBending energy, 5 x10-3Linear elastic energy, 1 x 10-2Transformation parameterisationStationary velocity fieldMaximum number of iterations per resolution level600, 300, 150ANTs registration:B. B. Avants et al. “Symmetric diffeomorphic image registration with cross-correlation: evaluating automated labeling of elderly and neurodegenerative brain." In: Medical image analysis 12.1 (2008), pp. 26-41. ISSN: 1361-8423 (Electronic). DOI: 10.1016/j.media.2007.06.004.B. B. Avants et al. “A reproducible evaluation of ANTs similarity metric performance in brain image registration". In: NeuroImage 54.3 (2011), pp. 2033-2044. ISSN: 1053-8119. DOI: https://doi.org/10.1016/j.neuroimage.2010.09.025.N. Tustison and B. Avants. “Explicit B-spline regularization in diffeomorphic image registration". In: Frontiers in Neuroinformatics 7 (2013). DOI: 10.3389/fninf.2013.00039.B. B. Avants et al. “The Insight ToolKit image registration frame-work". In: Frontiers in Neuroinformatics 8 (2014). DOI: 10.3389/fninf.2014.00044.Details of the ANTs registration implementation:Multi-resolution levels4Smoothing parameters2 x 2 x 0 x 0 mmGradient step0.1Update field variance in voxel space3Total field variance in voxel space0Update field knot spacing26 mmSimilarity metricCross-correlationMetric radius2Metric weight1Convergence parameter500 x 200 x 100 x 50
