Diffusion tensor-based analysis of white matter in dogs with idiopathic epilepsy

Katrin M Beckmann; Adriano Wang-Leandro; Frank Steffen; Henning Richter; Matthias Dennler; Rima Bektas; Ines Carrera; Sven Haller

doi:10.3389/fvets.2023.1325521

Diffusion tensor-based analysis of white matter in dogs with idiopathic epilepsy

Front Vet Sci. 2023 Dec 18:10:1325521. doi: 10.3389/fvets.2023.1325521. eCollection 2023.

Authors

Katrin M Beckmann^{1

2}, Adriano Wang-Leandro^{3

4}, Frank Steffen¹, Henning Richter³, Matthias Dennler³, Rima Bektas⁵, Ines Carrera⁶, Sven Haller^{7

8}

Affiliations

¹ Section of Neurology, Department of Small Animals, Vetsuisse Faculty Zurich, University of Zurich, Zurich, Switzerland.
² Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland.
³ Clinic for Diagnostic Imaging, Department of Diagnostics and Clinical Services, Vetsuisse-Faculty Zurich, University of Zurich, Zurich, Switzerland.
⁴ Department of Small Animal Medicine and Surgery, University of Veterinary Medicine Hannover, Hannover, Germany.
⁵ Section of Anaesthesiology, Department of Clinical Diagnostics and Services, Vetsuisse-Faculty Zurich, University of Zurich, Zurich, Switzerland.
⁶ Vet Oracle Teleradiology, Norfolk, United Kingdom.
⁷ Department of Surgical Sciences, Radiology, Uppsala University, Uppsala, Sweden.
⁸ Faculty of Medicine, University of Geneva, Geneva, Switzerland.

Abstract

Introduction: The understanding of epileptic seizure pathogenesis has evolved over time, and it is now generally accepted that not only are cortical and subcortical areas involved but also the connection of these regions in the white matter (WM). Recent human neuroimaging studies confirmed the involvement of the WM in several epilepsy syndromes. Neuroimaging studies investigating WM integrity with diffusion tensor imaging (DTI) in canine idiopathic epilepsy are lacking. This study aimed to test the hypothesis that WM diffusion changes can be found in dogs affected by idiopathic epilepsy.

Method: Twenty-six dogs with idiopathic epilepsy (15 Border Collies and 11 Greater Swiss Mountain dogs) and 24 healthy controls (11 Beagle dogs, 5 Border Collies, and 8 Greater Swiss Mountain dogs) were prospectively enrolled. Most dogs with idiopathic epilepsy (17/26) were enrolled within 3 months after seizure onset. Diffusion tensor imaging of the brain with 32 diffusion directions (low b value = 0 s/mm²; maximal b value = 800 s/mm²) was performed in a 3 Tesla scanner. Tract-based spatial statistics (TBSS), a voxel-based approach, was used to investigate changes in fractional anisotropy (FA) and mean diffusivity (MD) in the idiopathic epilepsy group compared to the healthy control group. Additionally, FA and MD were investigated in the region of corpus callosum and cingulate white matter in both groups.

Results: We observed subtle changes in WM DTI between the idiopathic epilepsy group and the healthy control group limited to cingulate WM, with a significantly lower FA in the idiopathic epilepsy group compared to the healthy control group in the region of interest (ROI) approach (p = 0.027). No significant changes were found between the idiopathic epilepsy group and the healthy control group in the TBSS analysis and in the corpus callosum in the ROI approach.

Conclusion: This study supports the cingulate area as a target structure in canine epilepsy. The subtle changes only might be explained by the short duration of epilepsy, small sample sizes, and the higher variability in canine brain anatomy. Furthermore, all included dogs showed generalized tonic-clonic seizures, possibly affected by generalized epilepsy syndrome, which are also associated with less pronounced DTI changes in humans than focal epilepsy syndromes.

Keywords: Border Collie; DTI; Greater Swiss Mountain dog; MRI; TBSS; canine; seizures; white matter integrity.

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This research was partially financially supported by the Albert-Heim-Stiftung and the Stiftung für Kleintiere der Vetsuisse-Fakultät Universität Zürich.