registration of functional pet and structural mr images
DESCRIPTION
Registration of functional PET and structural MR images. PVEOut satellite meeting Budapest, June 11 th 2004 Peter Willendrup & Claus Svarer Neurobiology Research Unit Copenhagen. Registration needed PVEOut. - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Registration of functional PET and structural MR images](https://reader036.vdocuments.net/reader036/viewer/2022081420/56815928550346895dc65046/html5/thumbnails/1.jpg)
Registration of functional PET and structural MR images
PVEOut satellite meeting
Budapest, June 11th 2004
Peter Willendrup & Claus Svarer
Neurobiology Research Unit
Copenhagen
![Page 2: Registration of functional PET and structural MR images](https://reader036.vdocuments.net/reader036/viewer/2022081420/56815928550346895dc65046/html5/thumbnails/2.jpg)
NRU, 2004
Registration needed PVEOut
• Structural MR and functional PET image has to be registered/aligned as the structural information is applied to each voxel in the functional image
• As image are coming from same subject only a rigid 6 parameter transformation has to be estimated:
– 3 translations (along X, Y and Z axis)– 3 rotations (around X, Y and Z axis)
![Page 3: Registration of functional PET and structural MR images](https://reader036.vdocuments.net/reader036/viewer/2022081420/56815928550346895dc65046/html5/thumbnails/3.jpg)
NRU, 2004
What automatic methods are available?
• West J, Fitzpatrick JM, Dawant BM, et al.
• Headmounted fiducials serves as ``Gold standard'' coregistration between the modalities (MR/CT/PET).• Coregistration parameters are kept for reference, and fiducials are removed from the datasets and
replaced by artificial noise.• Methods are tested ``blindly'' - no knowledge of the Gold standard answer.
Method Mean(mm) Med.(mm) Max.(mm) Method Mean(mm) Med.(mm) Max.(mm)Pluim 3.04 2.34 10.10 Rohlfing 3 3.72 3.40 10.00 Woods 1 2.67 2.35 5.81 Maintz 3.86 3.48 10.63 Rohlfing 5 3.15 2.60 8.09 Tanacs 1 5.31 3.56 16.80 Rohlfing 4 6.32 2.61 50.90 Luo 2 3.85 3.59 7.45 Rohlfing corrected 1 4.09 2.62 23.45 Collignon 4.63 3.64 12.73 Rohlfing corrected 2 12.29 2.74 115.57 Noz 4.57 3.64 11.37 Harkness 3.74 2.78 12.09 Ding 3.76 3.74 9.44 Pelizzari 3.36 2.89 9.99 Thevenaz 2 9.85 3.97 27.57 Thevenaz 3 4.52 2.98 14.34 Robb 3 4.21 4.01 9.44 Arata 2 3.00 3.01 5.43 Ashburner 2 4.14 4.20 7.46 Hsu 3.70 3.06 12.79 Malandain 4.24 4.21 8.54 Rohlfing 6 4.46 3.11 17.69 Nikou 1 4.24 4.29 8.62 Woods 2 3.00 3.14 5.97 Barillot 4.57 4.58 11.48 Ren 3.54 3.20 9.51 Thevenaz 1 4.86 5.03 10.13 Hill 3.50 3.25 9.32 Nikou 2 6.28 5.06 12.28 Tanacs 2 5.82 3.29 19.74 Ashburner 1 5.57 5.11 11.62 Robb 4 3.48 3.35 5.90 Capek 9.08 9.02 9.84
AIR
SPM
![Page 4: Registration of functional PET and structural MR images](https://reader036.vdocuments.net/reader036/viewer/2022081420/56815928550346895dc65046/html5/thumbnails/4.jpg)
NRU, 2004
Why are the automatic approaches not always a good idea?
• These methods are very well suited for registration of images where:
– There in the PET image is an equal uptake in all brain regions– There is no inhomogenity variation in the MR images
• This is not the case for all receptor PET images, e.g. 5-HT2A
altanserin PET images where there are very limited uptake in Cerebellum
Limited
uptake
![Page 5: Registration of functional PET and structural MR images](https://reader036.vdocuments.net/reader036/viewer/2022081420/56815928550346895dc65046/html5/thumbnails/5.jpg)
NRU, 2004
What manual methods have been proposed?
Many different approches exist in the litterature• Landmark based: "Graphics applied to medical image registration", G. Q. Maguire, Jr., M. E. Noz, H.
Rusinek, et al., Comput Graph Appl, 1991, vol. 11, pp. 20-29. • Surface based: "Accurate three-dimensional registration of CT, PET, and/or MR images of the brain", C.
A. Pelizzari, G. T. Y. Chen, D.R. Spelbring, R. R. Wechselbaum, and C-T. Chen, J Comput AssistTomogr, 1989, vol. 13, pp. 20-26.
• Image overlay: "Quantitative Comparison of Automatic and Interactive Methods for MRI-SPECT Image Registration of the Brain Based on 3-Dimensional Calculation of Error ”, Pfluger T, Vollmar C et al.: J Nucl Med 2000; 41:1823-1829
• Voxel based: "MRI-PET registration with automated algorithm", R. P. Woods, J. C. Mazziotta, and S. R. Cherry, J Comput Assist Tomogr, 1993, vol. 17, pp. 536-546.
![Page 6: Registration of functional PET and structural MR images](https://reader036.vdocuments.net/reader036/viewer/2022081420/56815928550346895dc65046/html5/thumbnails/6.jpg)
NRU, 2004
MARSMultiple Algorithms for Registration of Scans
• Modular design– The problem of coregistration can be divided into subtasks
• Data selection• Registration• Visualisation / Inspection• Parameter I/O• Reslicing / Re-Interpolation
– All subtasks realised by ‘plugins’ - easy inclusion of alternative method
– Different registration approaches benefit from shared code
![Page 7: Registration of functional PET and structural MR images](https://reader036.vdocuments.net/reader036/viewer/2022081420/56815928550346895dc65046/html5/thumbnails/7.jpg)
NRU, 2004
MARS
• Main program
• This is now included in pvelab
![Page 8: Registration of functional PET and structural MR images](https://reader036.vdocuments.net/reader036/viewer/2022081420/56815928550346895dc65046/html5/thumbnails/8.jpg)
NRU, 2004
MARS
• Subtask modules– Registration
• Interface to Air 5.0 - Roger P. Woods• Interface to SPM 2 - J. Ashburner et. al.• IIO (Interactive Image Overlay) - NRU *• IPS (Interactive Point Selection) - NRU *
– Visualisation• Inspect (NRU visualisation program) *
• Asterisk-marked will be further explained
![Page 9: Registration of functional PET and structural MR images](https://reader036.vdocuments.net/reader036/viewer/2022081420/56815928550346895dc65046/html5/thumbnails/9.jpg)
NRU, 2004
Registration 1: Interactive Image Overlay
![Page 10: Registration of functional PET and structural MR images](https://reader036.vdocuments.net/reader036/viewer/2022081420/56815928550346895dc65046/html5/thumbnails/10.jpg)
NRU, 2004
Registration 1: Interactive Image Overlay
Translation and rotation
of overlay image and surface
by keyboard commands
![Page 11: Registration of functional PET and structural MR images](https://reader036.vdocuments.net/reader036/viewer/2022081420/56815928550346895dc65046/html5/thumbnails/11.jpg)
NRU, 2004
Registration 1: Interactive Image Overlay
![Page 12: Registration of functional PET and structural MR images](https://reader036.vdocuments.net/reader036/viewer/2022081420/56815928550346895dc65046/html5/thumbnails/12.jpg)
NRU, 2004
Registration 2: Interactive Point Selection
![Page 13: Registration of functional PET and structural MR images](https://reader036.vdocuments.net/reader036/viewer/2022081420/56815928550346895dc65046/html5/thumbnails/13.jpg)
NRU, 2004
Registration 2: Interactive Point Selection
![Page 14: Registration of functional PET and structural MR images](https://reader036.vdocuments.net/reader036/viewer/2022081420/56815928550346895dc65046/html5/thumbnails/14.jpg)
NRU, 2004
Inspection of registration
OverlaySide by side
![Page 15: Registration of functional PET and structural MR images](https://reader036.vdocuments.net/reader036/viewer/2022081420/56815928550346895dc65046/html5/thumbnails/15.jpg)
NRU, 2004
Evaluation study: Setup
• Images (5 subjects)– T1 weighted MR images (MPRAGE)
– 18F-Altanserin 5HT-2A receptor images
– Simulated PET images
• Evaluation by 7 volunteers– 3 rounds of MR / Altanserin registration
– 1 round of MR / Simulated PET registration
– Registration order randomised
– Max. one ‘round’ of registrations pr. day
• Images also registered using SPM99 and Air 3.0
![Page 16: Registration of functional PET and structural MR images](https://reader036.vdocuments.net/reader036/viewer/2022081420/56815928550346895dc65046/html5/thumbnails/16.jpg)
NRU, 2004
Evaluation study: Simulated PET
• Simulated PET datasets – Good: known registration parameters
– Bad: “easy” for cost fct. Based methods
![Page 17: Registration of functional PET and structural MR images](https://reader036.vdocuments.net/reader036/viewer/2022081420/56815928550346895dc65046/html5/thumbnails/17.jpg)
NRU, 2004
Evaluation study: Altanserin PET
• Altanserin PET images– Bad: Lack of gold standard registration method
– Good: Real world ‘limited uptake’ images
![Page 18: Registration of functional PET and structural MR images](https://reader036.vdocuments.net/reader036/viewer/2022081420/56815928550346895dc65046/html5/thumbnails/18.jpg)
NRU, 2004
Evaluation study
• Error measure - Euclidean distance between transformation endpoints
• Evaluated for 1% evenly distributed brain voxels. • Mean and std. dev. calculated
• Mean transformation realized by 6-parameter estimation to mean of transformed voxels
MR PET
vvv BxAxE
![Page 19: Registration of functional PET and structural MR images](https://reader036.vdocuments.net/reader036/viewer/2022081420/56815928550346895dc65046/html5/thumbnails/19.jpg)
NRU, 2004
Evaluation study: Simulated PET
![Page 20: Registration of functional PET and structural MR images](https://reader036.vdocuments.net/reader036/viewer/2022081420/56815928550346895dc65046/html5/thumbnails/20.jpg)
NRU, 2004
Evaluation study: Altanserin PET
![Page 21: Registration of functional PET and structural MR images](https://reader036.vdocuments.net/reader036/viewer/2022081420/56815928550346895dc65046/html5/thumbnails/21.jpg)
NRU, 2004
Evaluation study: Result
SPM Air Mean manual
No Altanserin binding
should be seen in
Cerebellum,
Rotation problem? Too little binding in
Altanserin image,
Translation problem?
![Page 22: Registration of functional PET and structural MR images](https://reader036.vdocuments.net/reader036/viewer/2022081420/56815928550346895dc65046/html5/thumbnails/22.jpg)
NRU, 2004
• Two manual co-registration methods and the interface to two automatic methods have been implemented and incorporated in the PVEOut SW package (pvelab).
• Four registration methods are included:– Interface to SPM 2 (J. Ashburner et. al.)– Interface to Air (R. Woods)– IIO (NRU)– IPS (NRU)
• For FDG/flow type images, SPM and Air are preferred, with reported errors in the range 2-3 mm.
• For neuroreceptor type images, with limited binding in areas of the brain, the manual methods can be used and possibly preferred.
• Measured errors:
Registration: Conclusion
Simulated images F18-Altanserin images