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Retrospective 3D registration of trabecular bone MR images for longitudinal studies
Author(s) -
Magland Jeremy F.,
Jones Catherine E.,
Leonard Mary B.,
Wehrli Felix W.
Publication year - 2009
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.21551
Subject(s) - reproducibility , image registration , nuclear medicine , pixel , intraclass correlation , displacement (psychology) , computer science , artificial intelligence , medicine , computer vision , mathematics , image (mathematics) , statistics , psychotherapist , psychology
Purpose To evaluate an automatic 3D registration algorithm for serial high‐resolution images of trabecular bone (TB) in studies designed to evaluate the response of the trabecular architecture to intervention or disease progression. Materials and Methods An efficient algorithm for registering high‐resolution 3D images of TB is presented. The procedure identifies the six parameters of rigid displacement between two scans performed at different timepoints. By assuming a relatively small through‐plane rotation, considerable time is saved by combining the results of a collection of regional 2D registrations throughout the TB region of interest (ROI). The algorithm was applied to 26 pairs of MR images acquired 6 months apart. Reproducibility of local TB structural parameters (plate, rod, and junction density) computed in manually selected regions were compared between baseline and registered follow‐up images. Results All 26 registrations were completed successfully in less than 30 seconds per image pair. The resampled follow‐up images agreed with baseline to around one pixel throughout the volume at 137 × 137 × 410 μm 3 image resolution. Structural parameters in each region correlated well from baseline to follow‐up with intraclass correlation coefficients ranging between 85%–97% for TB plate density. Interregional variations in the parameters were large as compared with intraregion reproducibility. Conclusion The proposed algorithm was successful in automatically registering baseline and follow‐up TB images in a translational study, and may be useful in regional analyses in longitudinal MR studies of TB architecture. J. Magn. Reson. Imaging 2009;29:118–126. © 2008 Wiley‐Liss, Inc.