Quality Improvements for Multi-Modal Neuroimaging

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Quality Improvementsfor Multi-Modal Neuroimaging

• Mika Seppä
• Brain Research Unit / LTL
• AMI-Centre
• Helsinki University of Technology

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3 central stages
1. Registration
2. Resampling
3. Visualization
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1. Registration

• Match metric
• Single-modal registration
• sum of squared differences
• Multi-modal registration
• mutual information

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MI artifacts

• Images aligned
• Same pixel/voxel sizes
• Registration bias
• Local maxima
• Continuous sampling
• higher-order method

MI
offset (pixels)
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2. Resampling

• Very common operation
• geom. correction, motion correction, group
  average etc.

...
15 x
SNR 10log10(?s2/?e2)
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Two-stage resampling
SNR (dB)
Time (ms)
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3. Visualization
800 fps
0.1-5 fps
120 fps
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Seppä (2007). On continuous sampling and
sub-sample accuracy in mutual-information
registration. TKK Report, TKK-KYL-017. Seppä
(2007). High-quality two-stage resampling for 3-D
volumes in medical imaging. Medical Image
Analysis, 11346-360. Seppä, Hämäläinen (2005).
Visualizing human brain surface from T1-weighted
MR images using texture-mapped triangle meshes.
NeuroImage, 261-12. Hiltunen, Suortti, Arvela,
Seppä, Joensuu, Hari (2005). Diffusion tensor
imaging and tractography of distal peripheral
nerves at 3 T. Clinical Neurophysiology,
1162315-2323.
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