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Shape (but not volume) changes in the thalami in Parkinson disease.

McKeown MJ, Uthama A, Abugharbieh R, Palmer S, Lewis M, Huang X - BMC Neurol (2008)

Bottom Line: No significant differences in volume were detected in the thalami between eighteen normal subjects and eighteen PD subjects groups.However significant (p < 0.03) shape differences were detected between the Left vs.Although not directly discernable at the resolution of standard MRI, previous pathological studies would suggest that the shape changes detected in this study represent degeneration in the centre median-parafascicular (CM-Pf) complex, an area known to represent selective non-dopaminergic degeneration in PD.

View Article: PubMed Central - HTML - PubMed

Affiliation: Pacific Parkinson's Research Center, University of British Columbia, Vancouver, Canada. mmckeown@interchange.ubc.ca

ABSTRACT

Background: Recent pathological studies have suggested that thalamic degeneration may represent a site of non-dopaminergic degeneration in Parkinson's Disease (PD). Our objective was to determine if changes in the thalami could be non-invasively detected in structural MRI images obtained from subjects with Parkinson disease (PD), compared to age-matched controls.

Results: No significant differences in volume were detected in the thalami between eighteen normal subjects and eighteen PD subjects groups. However significant (p < 0.03) shape differences were detected between the Left vs. Right thalami in PD, between the left thalami in PD and controls, and between the right thalami in PD and controls using a recently-developed, spherical harmonic-based representation.

Conclusion: Systematic changes in thalamic shape can be non-invasively assessed in PD in vivo. Shape changes, in addition to volume changes, may represent a new avenue to assess the progress of neurodegenerative processes. Although not directly discernable at the resolution of standard MRI, previous pathological studies would suggest that the shape changes detected in this study represent degeneration in the centre median-parafascicular (CM-Pf) complex, an area known to represent selective non-dopaminergic degeneration in PD.

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Related in: MedlinePlus

Two sets typical thalami registered and shown on brain from a PD subject. Note that the registration here is solely for visualization purposes, and is not required for the calculation of shape differences. Also, although the thalami here were first smoothed with a 12 mm FWHM Gaussian kernel for visualization purposes, no smoothing was performed for the shape analysis and group comparison.
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Figure 2: Two sets typical thalami registered and shown on brain from a PD subject. Note that the registration here is solely for visualization purposes, and is not required for the calculation of shape differences. Also, although the thalami here were first smoothed with a 12 mm FWHM Gaussian kernel for visualization purposes, no smoothing was performed for the shape analysis and group comparison.

Mentions: In order to better visualize and intuitively assess the shape differences in thalami between PD subjects and controls, we took thalami that had "typical" feature vectors (i.e. feature vectors closest to the mean of each group) and assumed that they represented exemplar shapes. We then spatially aligned these exemplar shapes (Figure 2). There appeared to be greater differences in the left thalami between controls and PD subjects. The largest differences appeared to be along the dorsal surface. Note that the registration of the thalami in this instance was solely for visualization purposes and was not incorporated into the analysis.


Shape (but not volume) changes in the thalami in Parkinson disease.

McKeown MJ, Uthama A, Abugharbieh R, Palmer S, Lewis M, Huang X - BMC Neurol (2008)

Two sets typical thalami registered and shown on brain from a PD subject. Note that the registration here is solely for visualization purposes, and is not required for the calculation of shape differences. Also, although the thalami here were first smoothed with a 12 mm FWHM Gaussian kernel for visualization purposes, no smoothing was performed for the shape analysis and group comparison.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2386499&req=5

Figure 2: Two sets typical thalami registered and shown on brain from a PD subject. Note that the registration here is solely for visualization purposes, and is not required for the calculation of shape differences. Also, although the thalami here were first smoothed with a 12 mm FWHM Gaussian kernel for visualization purposes, no smoothing was performed for the shape analysis and group comparison.
Mentions: In order to better visualize and intuitively assess the shape differences in thalami between PD subjects and controls, we took thalami that had "typical" feature vectors (i.e. feature vectors closest to the mean of each group) and assumed that they represented exemplar shapes. We then spatially aligned these exemplar shapes (Figure 2). There appeared to be greater differences in the left thalami between controls and PD subjects. The largest differences appeared to be along the dorsal surface. Note that the registration of the thalami in this instance was solely for visualization purposes and was not incorporated into the analysis.

Bottom Line: No significant differences in volume were detected in the thalami between eighteen normal subjects and eighteen PD subjects groups.However significant (p < 0.03) shape differences were detected between the Left vs.Although not directly discernable at the resolution of standard MRI, previous pathological studies would suggest that the shape changes detected in this study represent degeneration in the centre median-parafascicular (CM-Pf) complex, an area known to represent selective non-dopaminergic degeneration in PD.

View Article: PubMed Central - HTML - PubMed

Affiliation: Pacific Parkinson's Research Center, University of British Columbia, Vancouver, Canada. mmckeown@interchange.ubc.ca

ABSTRACT

Background: Recent pathological studies have suggested that thalamic degeneration may represent a site of non-dopaminergic degeneration in Parkinson's Disease (PD). Our objective was to determine if changes in the thalami could be non-invasively detected in structural MRI images obtained from subjects with Parkinson disease (PD), compared to age-matched controls.

Results: No significant differences in volume were detected in the thalami between eighteen normal subjects and eighteen PD subjects groups. However significant (p < 0.03) shape differences were detected between the Left vs. Right thalami in PD, between the left thalami in PD and controls, and between the right thalami in PD and controls using a recently-developed, spherical harmonic-based representation.

Conclusion: Systematic changes in thalamic shape can be non-invasively assessed in PD in vivo. Shape changes, in addition to volume changes, may represent a new avenue to assess the progress of neurodegenerative processes. Although not directly discernable at the resolution of standard MRI, previous pathological studies would suggest that the shape changes detected in this study represent degeneration in the centre median-parafascicular (CM-Pf) complex, an area known to represent selective non-dopaminergic degeneration in PD.

Show MeSH
Related in: MedlinePlus