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Updated: Aug 29, 2025
Diffusion Tensor Magnetic Resonance Imaging in the Analysis of Neurodegenerative Diseases
Published on: July 28, 2013
Comparison of Olfactory Tract Diffusion Measures Between Early Stage Parkinson's Disease Patients and Healthy
Margot Heijmans1, Amée F Wolters1,2, Yasin Temel1,3
1School for Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands.
Background:
MRI is a valuable method to assist in the diagnostic work-up of Parkinson's disease (PD). The olfactory tract (OT) has been proposed as a potential MRI biomarker for distinguishing PD patients from healthy controls.
Objective:
This study aims to further investigate whether diffusion measures of the OT differ between early stage PD patients and healthy controls.
Methods:
Twenty hyposmic/anosmic PD patients, 65 normosmic PD patients, and 36 normosmic healthy controls were evaluated and a 7T diffusion weighted image scan was acquired. Manual seed regions of interest were drawn in the OT region. Tractography of the OT was performed using a deterministic streamlines algorithm. Diffusion measures (fractional anisotropy and mean- radial- and axial diffusivity) of the generated streamlines were compared between groups.
Results:
Diffusion measures did not differ between PD patients compared to healthy controls and between hyposmic/anosmic PD patients, normosmic PD patients, and normosmic healthy controls. A positive correlation was found between age and mean- and axial diffusivity within the hyposmic/anosmic PD subgroup, but not in the normosmic groups. A positive correlation was found between MDS-UPDRSIII scores and fractional anisotropy.
Conclusion:
This study showed that fiber tracking of the OT was feasible in both early stage PD and healthy controls using 7T diffusion weighted imaging data. However, 7T MRI diffusion measures of the OT are not useful as an early clinical biomarker for PD. Future work is needed to clarify the role of other OT measurements as a biomarker for PD and its different subgroups.
Insights
Diffusion MRI of the olfactory tract (OT) did not differentiate early Parkinson's disease (PD) patients from controls. While feasible, OT diffusion measures are not yet a reliable biomarker for early PD diagnosis.
Area of Science:
- Neuroimaging
- Neurology
- Biomarker Discovery
Background:
- Magnetic Resonance Imaging (MRI) aids Parkinson's disease (PD) diagnosis.
- The olfactory tract (OT) is a potential MRI biomarker for PD detection.
Purpose of the Study:
- Investigate diffusion measures of the OT in early PD patients versus healthy controls.
- Assess the utility of OT diffusion MRI as an early PD biomarker.
Main Methods:
- 7T diffusion-weighted imaging in 20 hyposmic/anosmic PD patients, 65 normosmic PD patients, and 36 normosmic controls.
- Tractography of the OT using deterministic streamlines.
- Comparison of diffusion measures (FA, MD, RD, AD) between groups.
Main Results:
- No significant differences in OT diffusion measures between PD patients and controls.
- No differences between hyposmic/anosmic PD, normosmic PD, and normosmic controls.
- Positive correlation between age and diffusivity in hyposmic/anosmic PD; correlation between MDS-UPDRSIII and FA.
Conclusions:
- Fiber tracking of the OT is feasible with 7T MRI in early PD and controls.
- 7T MRI diffusion measures of the OT are not effective early clinical biomarkers for PD.
- Further research is needed to explore other OT measurements as PD biomarkers.
