Affiliations: [a] Department of Neurology, University Hospital Münster, Münster, Germany
| [b] Department of Nuclear Medicine, University Hospital Münster, Münster, Germany
| [c] Institute of Epidemiology and Social Medicine, University of Münster, Münster, Germany
| [d] Department of Nuclear Medicine, German Oncology Center, Limassol, Cyprus
Correspondence:
[*]
Correspondence to: Julia Krämer, MD, Department of Neurology, Westfälische Wilhelms University, Albert-Schweitzer-Campus 1, Gebäude A1, 48149 Münster, Germany. Tel.: +49 251 8346811; Fax: +49 251 8344414; E-mail: julia.kraemer@ukmuenster.de.
Note: [1] These authors contributed equally to this work.
Abstract: Background:Due to suboptimal sensitivity and specificity of structural and molecular neuroimaging tools, the diagnosis of behavioral variant frontotemporal dementia (bvFTD) remains challenging. Objective:Investigation of the sensitivity of diffusion tensor imaging (DTI) and fluorodeoxyglucose positron emission tomography (FDG-PET) to detect cerebral alterations in early stages of bvFTD despite inconspicuous conventional MRI. Methods:Thirty patients with early stages of bvFTD underwent a detailed neuropsychological examination, cerebral 3T MRI with DTI analysis, and FDG-PET. After 12 months of follow-up, all patients finally fulfilled the diagnosis of bvFTD. Individual FDG-PET data analyses showed that 20 patients exhibited a “typical” pattern for bvFTD with bifrontal and/or temporal hypometabolism (bvFTD/PET+), and that 10 patients showed a “non-typical”/normal pattern (bvFTD/PET-). DTI data were compared with 42 healthy controls in an individual and voxel-based group analysis. To examine the clinical relevance of the findings, associations between pathologically altered voxels of DTI or FDG-PET results and behavioral symptoms were estimated by linear regression analyses. Results:DTI voxel-based group analyses revealed microstructural degeneration in bifrontal and bitemporal areas in bvFTD/PET+ and bvFTD/PET- groups. However, when comparing the sensitivity of individual DTI data analysis with FDG-PET, DTI appeared to be less sensitive. Neuropsychological symptoms were considerably related to neurodegeneration within frontotemporal areas identified by DTI and FDG-PET. Conclusion:DTI seems to be an interesting tool for detection of functionally relevant neurodegenerative alterations in early stages of bvFTD, even in bvFTD/PET- patients. However, at a single subject level, it seems to be less sensitive than FDG-PET. Thus, improvement of individual DTI analysis is necessary.
