Research article

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

Martin J McKeown^{* 1,2,3,4} , Ashish Uthama^{* 4} , Rafeef Abugharbieh^{* 2,4} , Samantha Palmer^{* 1} , Mechelle Lewis^{* 5} and Xuemei Huang^{* 5}

¹Pacific Parkinson's Research Center, University of British Columbia, Vancouver, Canada

²Brain Research Centre, University of British Columbia, Vancouver, Canada

³Department of Medicine (Neurology), University of British Columbia, Vancouver, Canada

⁴Biomedical Signal and Image Computing Lab, Department of Electrical and Computer Engineering, University of British Columbia, Vancouver, Canada

⁵Department of Neurology, University of North Carolina, Chapel Hill, NC, USA

author email corresponding author email* Contributed equally

BMC Neurology 2008, 8:8doi:10.1186/1471-2377-8-8

Published:	16 April 2008

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.