Program Information
Comparing Mutual Information and Gradient Magnitude Metrics for Deformable Image Registration
I Gertsenshteyn1*, N Tyagi2 , R Farjam 2 , A Apte2 , G Sharp1 , (1) Massachusetts General Hospital, Boston, MA , (2) Memorial Sloan-Kettering Cancer Center, New York , NY
Presentations
TU-CD-BRA-2 (Tuesday, July 14, 2015) 10:15 AM - 12:15 PM Room: Ballroom A
Purpose: Deformable image registration between CT and MRI remains a challenge due to variability in contrast, homogeneity, and field of view. This study aims to determine whether an optimized Mutual Information (MI) or Gradient Magnitude (GM) metric provides favorable results in the head and neck region.
Methods: Head and neck CT and MR images were acquired for 14 patients as part of an MRI simulation study with a dual echo mDixon (in phase) T1 fast field echo sequence. Each pair of scans is registered with MRI as the reference image using the GM and MI metrics, where MI was optimized by controlling histogram parameters. Results are observed visually, and quantitatively measured by comparing Dice coefficient and Hausdorff distance of manually contoured bone structures.
Results: Using the optimized GM metric, the average Dice coefficient is 0.52 ± 0.16; the average Hausdorff distance is 7.5 ± 1.9 mm. Using the optimized MI metric, the average Dice coefficient is 0.55 ± 0.085; the average Hausdorff distance is 6.6 ± 1.4 mm.
Conclusion: While both metrics performed similarly, the MI metric has a higher Dice coefficient than the GM metric, and a lower Hausdorff distance. This suggests image registration with the Mutual Information metric may be preferred.
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