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Updated: Dec 27, 2025
Diffusion Tensor Magnetic Resonance Imaging in the Analysis of Neurodegenerative Diseases
Published on: July 28, 2013
Insights into disseminated MS brain pathology with multimodal diffusion tensor and PET imaging
Svetlana Bezukladova1, Jouni Tuisku1, Markus Matilainen1
1From the Turku PET Centre (S.B., J.T., M. Matilainen, A.V., M.N., S.S., M.S., M. Mohammadian, V.S., S.L., J.R., J.O.R., E.R., L.A.), University of Turku and Turku University Hospital; Division of Clinical Neurosciences (A.V., M.N., S.S., M.S., S.L., E.R., L.A.), Turku University Hospital; and Department of Medical Physics (V.S.), Division of Medical Imaging, Turku University Hospital, Finland.
Objective:
To evaluate in vivo the co-occurrence of microglial activation and microstructural white matter (WM) damage in the MS brain and to examine their association with clinical disability.
Methods:
18-kDa translocator protein (TSPO) brain PET imaging was performed for evaluation of microglial activation by using the radioligand [11C](R)-PK11195. TSPO binding was evaluated as the distribution volume ratio (DVR) from dynamic PET images. Diffusion tensor imaging (DTI) and conventional MRI (cMRI) were performed at the same time. Mean fractional anisotropy (FA) and mean (MD), axial, and radial (RD) diffusivities were calculated within the whole normal-appearing WM (NAWM) and segmented NAWM regions appearing normal in cMRI. Fifty-five patients with MS and 15 healthy controls (HCs) were examined.
Results:
Microstructural damage was observed in the NAWM of the MS brain. DTI parameters of patients with MS were significantly altered in the NAWM compared with an age- and sex-matched HC group: mean FA was decreased, and MD and RD were increased. These structural abnormalities correlated with increased TSPO binding in the whole NAWM and in the temporal NAWM (p < 0.05 for all correlations; p < 0.01 for RD in the temporal NAWM). Both compromised WM integrity and increased microglial activation in the NAWM correlated significantly with higher clinical disability measured with the Expanded Disability Status Scale score.
Conclusions:
Widespread structural disruption in the NAWM is linked to neuroinflammation, and both phenomena associate with clinical disability. Multimodal PET and DTI allow in vivo evaluation of widespread MS pathology not visible using cMRI.
