Tract-specific damage at spinal cord level in pure hereditary spastic paraplegia type 4: a diffusion tensor imaging study

• Published in: Journal of neurology Vol. 269; no. 6; pp. 3189 - 3203
• Main Authors: Navas-Sánchez, Francisco J., Marcos-Vidal, Luis, de Blas, Daniel Martín, Fernández-Pena, Alberto, Alemán-Gómez, Yasser, Guzmán-de-Villoria, Juan A., Romero, Julia, Catalina, Irene, Lillo, Laura, Muñoz-Blanco, José L., Ordoñez-Ugalde, Andrés, Quintáns, Beatriz, Sobrido, María-Jesús, Carmona, Susanna, Grandas, Francisco, Desco, Manuel
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.06.2022; Springer Nature B.V
• Subjects: Anisotropy; Dorsal columns; Hereditary spastic paraplegia; Image processing; Magnetic resonance imaging; Medicine; Medicine & Public Health; Neurodegeneration; Neuroimaging; Neurology; Neuroradiology; Neurosciences; Original Communication; Paralysis; Patients; Pyramidal tracts; Spasticity; Spinal cord; Thorax; Hereditary spastic paraplegia; Spinal cord; Corticospinal tract; Diffusion tensor imaging
• ISSN: 0340-5354; 1432-1459; 1432-1459
• DOI: 10.1007/s00415-021-10933-8

Background SPG4 is a subtype of hereditary spastic paraplegia (HSP), an upper motor neuron disorder characterized by axonal degeneration of the corticospinal tracts and the fasciculus gracilis. The few neuroimaging studies that have focused on the spinal cord in HSP are based mainly on the analysis of structural characteristics. Methods We assessed diffusion-related characteristics of the spinal cord using diffusion tensor imaging (DTI), as well as structural and shape-related properties in 12 SPG4 patients and 14 controls. We used linear mixed effects models up to T3 in order to analyze the global effects of 'group' and 'clinical data' on structural and diffusion data. For DTI, we carried out a region of interest (ROI) analysis in native space for the whole spinal cord, the anterior and lateral funiculi, and the dorsal columns. We also performed a voxelwise analysis of the spinal cord to study local diffusion-related changes. Results A reduced cross-sectional area was observed in the cervical region of SPG4 patients, with significant anteroposterior flattening. DTI analyses revealed significantly decreased fractional anisotropy (FA) and increased radial diffusivity at all the cervical and thoracic levels, particularly in the lateral funiculi and dorsal columns. The FA changes in SPG4 patients were significantly related to disease severity, measured as the Spastic Paraplegia Rating Scale score. Conclusions Our results in SPG4 indicate tract-specific axonal damage at the level of the cervical and thoracic spinal cord. This finding is correlated with the degree of motor disability.